The role of host plants and parasitoids on the abundanceof spring populations of Heliothis spp. in Arizona

Item Type text; Thesis-Reproduction (electronic)

Authors Rathman, Robin Jean

Publisher The University of Arizona.

Rights Copyright © is held by the author. Digital access to this materialis made possible by the University Libraries, University of Arizona.Further transmission, reproduction or presentation (such aspublic display or performance) of protected items is prohibitedexcept with permission of the author.

Download date 19/08/2018 09:15:10

Link to Item http://hdl.handle.net/10150/557650

THE ROLE OF HOST PLANTS AND PARASITOIDS ON

THE ABUNDANCE OF SPRING POPULATIONS

OF HELIOTHIS SPP. IN ARIZONA

by

Robin Jean Rathman

A Thesis Submitted to the Faculty of the

DEPARTMENT OF ENTOMOLOGY

In Partial Fulfillment of the Requirements For the Degree of

MASTER OF SCIENCE

In the G raduate College

THE UNIVERSITY OF ARIZONA

1 9 8 1

STATEMENT BY AUTHOR

This thesis has been subm itted in partial fulfillment of req u ire ­ments for an advanced degree at The U niversity of Arizona and is deposited in the U niversity L ibrary to be made available to borrow ers under rules of the L ibrary .

Brief quotations from th is thesis are allowable without special perm ission, provided th a t accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of th is m anuscript in whole or in p a rt may be granted by the head of the major departm ent or the Dean of the Graduate College when in his judgment the proposed use of the material is in the in te rests of scholar­ship. In all o ther in stances, however, permission must be obtained from the au thor.

SIGNED: j s&tLr

APPROVAL BY THESIS DIRECTOR

This thesis has been approved on the date shown below:

T. F. WATSON Professor of Entomology

ACKNOWLEDGMENTS

I would like to exp ress my sincerest appreciation to my major

p ro fessor. D r. Theo F. Watson, for his patience, guidance, in te re s t,

and encouragem ent th roughout the course of th is research . I would

also like to thank D rs. Roger T . Huber and H arry M. Graham for review­

ing th is m anuscript and serv ing on my graduate committee. I am ap p re ­

ciative of the assistance of D r. Floyd G. Werner in identify ing parasito ids

collected in th is s tu d y .

I am especially gratefu l to Scott Tollefson for his advice and

enthusiasm and to Joel Floyd for his photographs.

I would like to thank my paren ts for th e ir support and under­

stand ing .

iii

TABLE OF CONTENTS

LIST OF T A B L E S ..................................................................................... vi.

LIST OF ILLUSTRATIONS.................................................................................. vii

A BSTR A CT...............................................................................................................viii

INTRODUCTION ....................................................................................................... 1

LITERATURE REVIEW............................................................................................... 3

Seasonal H istory and Food Habits of Heliothis sppEmergence from D ia p a u s e .........................................H ost-plant S e lec tio n ......................................................Natural E n em ies................................................................................... 11

MATERIALS AND M ETHOD S............................................................... 15

R ESU LTS...................................................................................................................... 20

Rainfall D a t a .................................................................................................. 20Field Samples, 1979 .......................................................................................... 21Field Samples, 1980 ...................................................................................... 22Miscellaneous P lants Sam pled...................................................................... 23Plant D escriptions ......................................................... 24

Sphaeralcea coulteri (A ts .) G ra y .....................................................Erodlum cicutarium (L.) L 'H er........................................................... 24Erlgeron d ivergens T o rr. & G r a y ................................................. 25Cicer arietinum L. .............................................................................. 25Caesalpinnia gilliesii Wall...................................................................... 27Proboscidea parv iflora (W o o to n ) ..................................................... 27Hoffmanseggia densiflora B en th .......................................................... 27

Mortality on D ifferent Host P l a n t s ............................................................. 29Common Parasitoid S p e c ie s .............................................................................. 33H ost-plant S p e c if ic i ty ...................................................................................... 35Pheromone Monitor T r a p s ............................................................................. 37Unit Area S am ples.......................................................................................... 38

D IS C U S S IO N ........................................................................................................... 39

SUMMARY....................................................................................................................... 47

APPENDIX A: PLANT SPECIES SAMPLED FOR HELIOTHISSPP. IN 1979 48

Page

'

CO LO

CO

V

APPENDIX B

TABLE OF CONTENTS—Continued

Page

: PLANT SPECIES SAMPLED FOR HELIOTHISSPP. IN 1980 ...................................................................... 50

REFERENCES 52

LIST OF TABLES

1. Rainfall recorded a t the Casa Grande Ruins NationalMonument, Casa G rande, Arizona, October th roughMay, 1978-79 and 1979-80 ................................................................ 20

2. Species composition of Heliothis on th ree sp ring hostp lants in Pinal County in 1979 ..................................................... 22

3. Species composition of Heliothis on th ree sp ring andearly summer host p lan ts in Pinal County in 1980 ................. 23

4. Summary of Heliothis v irescens host p lants recordedduring sp ring 1979 and 1980 su rveys in centralA r i z o n a ................................................................................. 31

5. Relative parasitism of th ree Heliothis spp . on d ifferen thost plants in cen tral Arizona in 1979 ......................................... 32

6. Relative parasitism of th ree Heliothis spp . on d ifferenthost p lants in cen tral Arizona in 1980 ......................................... 32

7. Relative abundance of Heliothis sp p . larvae on d ifferen tsp ring host p lants in Pinal C ounty, A riz o n a ............................. 34

8. Species of parasito ids found on Heliothis spp . incentral Arizona during the sp rings of 1979 and 1980 . . . . 36

9. Host utilization by Heliothis s p p . on a given host p lantin .the sp rings of 1979 and 1980 in cen tral A r iz o n a ................. 37

Table Page

vi/

LIST OF ILLUSTRATIONS

1. Inner surface of la te -in s ta r larvae of tobaccobudworm (left) showing prom inent retinaculum and of bollworm (right) showing concave inner surface without the r e t in a c u lu m ................................................. 17

2. Lateral view of abdominal segment eight of la te -in s ta r tobacco budworm larva showing d istinctmicrospines on the t u b e r c l e ......................................................... 18

3. Lateral view of abdominal segment eight of la te -in s ta r cotton bollworm larva showing tuberclewithout m icro sp ines........................................................................... 18

4. Tobacco budworm larvae on red stem filaree,Erodium c ic u ta r iu m .......................................................................... 26

Figure Page

5. Tobacco budworm larva feeding on unopened flowerof yellow b ird -o f-p a rad ise , Caesalplnnia gilliesii . . . . . 28

6. Seasonal sequence of some p lan ts found to behosts of the tobacco budworm in A r iz o n a ................................. 30

vii

ABSTRACT

Surveys were conducted in 1979 and 1980 to determine the species

of wild and cultivated p lants utilized as hosts by the tobacco budworm,

Heliothis v irescens (F ab ric iu s), and the cotton bollworm, Heliothis zea

(Boddie) in the early -season in central Arizona before cotton begins

squaring . Tobacco budworm and cotton bollworm larvae were collected

from nine plant species. D uring April and May in 1979 large Heliothis spp .

populations were found on redstem filaree, Erodlum cicutarium (L .) , a

common d esert weed. Yellow b ird -o f-parad ise , Caesalpinnia gilliesii W all.,

and garbanzo bean, Cicer arietinum L . , were prim ary sp ring hosts in

1980. An obscure species, Heliothis phloxiphaga (Grote and Robinson),

was collected on daisy fleabane, Erigeron divergens T o rr. & G ray, in

large numbers in 1979 and on Erodium cicutarium in 1979 and 1980.

Seven species of hym enopterous parasito ids were identified from

the 1979 and 1980 collections: Campoletis sonorensis (C am .), Pristom erus

sp inator (F .) , Hyposoter exiguae (Vierreck) (Family Ichneum onidae);

Microplitis croceipes (C ressoh), Rogas perp lexus Gaham ., Cardiochiles

seminiger (Cresson) (Family Braconidae); and Spilochalcis sp . (Family

Chalcidae). Additionally, four species of dipterous parasito ids in the

family Tachinidae emerged from collected larvae: Lespesia archippivora

(R iley), Eucelatoria s p . , Chaetogaedia s p . , and A rchytas marmoratus

(T n s .).

viii

INTRODUCTION

Among the most damaging pests of ag ricu ltu re in the United

States are the cotton bollworm, Heliothis zea (Boddie), and the tobacco

budworm, Heliothis v irescens (F ab ric iu s). They a ttack a wide range of

valuable crops, including co tton , corn , tomatoes, soybeans, grain so r­

ghum, and tobacco.

Heliothis sp p . have shown g rea t adaptability in developing

resistance to insecticides, and the chemical in d u stry has been hard

p ressed to meet the demands for effective chemicals to combat the Helio­

th is problem in certa in a reas. Perhaps th is problem is best illu stra ted

by the demise of the cotton in d u stry in the Tampico-Mante area in the

S tate of Tamaulipas, Mexico, due , in p a r t , to methyl parathion res is­

tance in the tobacco budworm (Lukefahr 1970).

The tobacco budworm did not become a major p est on cotton in

Arizona until 1971 (Watson 1974). Recorded resistance to methyl p a ra ­

thion in Arizona (Crowder, Tollefson, and Watson 1979) and the potential

for developing resistance to the newly developed syn thetic py re th ro ids

make it imperative th a t da ta be available on all factors th a t could influence

the population dynamics of the species. It is essential th a t the in te rac ­

tions between a p est population and associated environm ental factors be

determ ined, because the success of most management program s is based

on the facts known about the p e s t 's ecology (Davis 1974).

The life system of an insect population is th a t p a r t of the eco­

system th a t determ ines its existence, abundance, and evolution (Clark

1

et al. 1967). This concept was developed as a guide to understand ing

population dynamics. T raditionally , ecologists have considered the host

plant (s) as a major element in the life system of insects with emphasis

usually placed on host abundance.

Lincoln (1972) noted th a t seasonal abundance of the cotton boll-

worm and tobacco budworm is strongly influenced by the sequential

availability of favorable hosts. A continuous series of host p la n ts , both

cultivated and noncultivated , is requ ired to support these species during

th e ir active period (Snow and Brazzel 1965). The objective of th is re ­

search was to study Heliothis spp . populations and associated parasito ids

on sp ring host p lants in cen tral Arizona.

LITERATURE REVIEW

The tobacco budworm is apparen tly most abundant in the tro p ic s ,

and i ts range extends through the West Indies and South America as far

south as A rgentina (Neunzig 1969). The species is frequen tly encoun­

tered in the sou thern United S tates and at times is found as fa r north

as O ntario, Canada (Forbes 1954).

Heliothis spp . a re ra th e r general fee d e rs , having a wide varie ty

of cultivated and wild host p lants (Snow and Brazzel 1965). Tietz (1972)

listed 31 host p lants for the tobacco budworm and 106 hosts for the cotton

bollworm. Corn appears to be the p re fe rred host p lant of H. zea;

tobacco and cotton are major hosts of H. v irescens (Lincoln 1972).

Lacroix (1936) listed H. v irescens as an occasional pest of tobacco in

Connecticut. The f ir s t reference to th is species attacking cotton was

made by Wilson (1923) in the Virgin Islands. No mention of the tobacco

budworm damaging cotton in the continental United S ta tes, however,

occurred until Folsom reported i t in Louisiana in 1936.

Seasonal H istory and Food Habits of Heliothis spp .

The seasonal h isto ry and food habits of II. v irescens were studied

as early as 1926 by Chamberlin and Tenhet (1926a) in the sou theastern

United S tates. Tobacco, Nicotiana s p . , and beggarw eed, Meioboma s p . ,

were im portant food p lan ts. B arber (1937) listed Florida beggarw eed, M.

p u rp u re a , as an im portant fall host in eastern Georgia. Hambleton (1944)

3

4

listed the following species as host p lants in the Canete Valley, Peru :

Cajanus cajan . Geranium s p . , Petunia s p . , Verbena s p . , C ucurbita s p . ,

and Rosa sp .

Snow and Brazzel (1965) listed 81cultivated and 11 wild species of

plants as hosts in M ississippi. Among the im portant wild p lants were

toadflax , Linaria canadensis, and d ee rg rass , Rhexia sp . Neunzig (1963)

also listed these two p lants as im portant a lternate hosts in easte rn North

Carolina. Snow, Hamm, and Brazzel (1966) found Geranium carolinianum

to be an early host of Heliothis spp . in the sou theastern United S ta tes.

In the Lower Rio Grande Valley, Texas (Graham and Robertson 1970) and

in Brownsville, Texas (Graham, H ernandez, and Llanes 1972) wild tobacco,

Nicotiana rep an d a , was reported as an im portant early-season host.

Payne and Polles (1973) found larvae of Heliothis spp . feeding on

the foliage, terminal b u d s, and nu tle ts of pecans in Georgia. In coastal

southern California, H. v irescens is an occasional pest of lettuce (Oatman

and P lainer 1972), and a t S t. Croix, U .S . Virgin Islands, major hosts

attacked are pigeon pea, Cajan cajan , and the malvaceous p lan t, B astardia

vlscosa (Snow et al. 1974). Harding (1976) conducted a su rvey during

1969-1973 in the Lower Rio Grande Valley of Texas; cotton, soybeans,

and tomatoes were the only cultivated hosts used by the tobacco budworm.

Sunflowers (Helianthus sp.) were the most common wild hosts; husk tomato

(Solanum s p . ) , passion flower (Passiflora s p . ) , and vervain (Verbena s p .)

were also su itab le.

O ther hosts of H. v irescens cited in the lite ra tu re include sesame,

Sesamum indicum (R ivers, Meisch, and Hamman 1965), cultivated snap­

dragon, Antirrhinum majus (Tilden 1968) and cultivated sunflow ers,

5

Helianthus s p . (T eetes, Randolph, and Kinman 1970). L aster, M artin,

and Pair (1976) collected tobacco budworm larvae from burcucum ber,

Slcyos angu la ta , from 1973-75 near Stoneville, M ississippi. B atra (1979)

listed the quickw eeds, Galinsago ciliata and G. parv iflo ra , as having

H. v irescens associated with them. In a more recen t s tu d y , Stadel-

bacher (1979) described the influence of Geranium dissectum on the

population dynamics of H. zea and H. v irescens in the Mississippi Delta.

In sou thern Arizona, H. zea has been collected on a wild mallow

species, Sphaeralcea emoryi (Stoner 1972). Sluss and Graham (1979)

collected Heliothis spp . from roses in Peoria, Arizona, and from yellow

b ird -o f-parad ise , Caesalpinnia gilliesii, near Tucson, Arizona.

The preceding repo rts show th a t the species composition of

host-p lan t complexes of Heliothis spp . varies widely between geographic

regions and agroecosystem s. Brazzel e t al. (1953) have suggested th a t

these host relationship differences can be explained by regional d iffer­

ences in the availability of wild and cultivated host p lants or can possibly

be a ttrib u ted to the presence of biological races. Roach (1975) sta ted

th a t Heliothis populations, especially those in early sp ring and fall,

depend on only a few major p lants species. A pparently , both species of

Heliothis build up to damaging num bers on cultivated hosts and use wild

hosts to maintain the species when cultivated hosts are unavailable

(Harding 1976).

Emergence from Diapause

The tobacco budworm is active throughout the w inter in the Lower

Rio Grand Valley, Texas (Fife and Graham 1966; Graham and Robertson

1970) bu t not in sou thern Louisiana (Brazzel e t al. 1953) or in central

Arizona (Potter and Watson n .d . a ) , where diapausing pupae constitu te

the dormant stage. Populations of Heliothis sp p . begin increasing in the

late sp ring and early summer following emergence from diapause. Fife and

Graham (1966) monitored the emergence of H. v irescens and H. zea from

cotton and pepper fields near Brownsville, T exas. Adult tobacco bud-

worms were found from early February until late May; peak emergence

was in March. In a similar s tudy in Tucson, Arizona, by Fye and

C arranza (1973), g rea test emergence was from late April to mid-May.

Potter and Watson (n .d .b ) collected pupae from cotton fields near La

Palma, Arizona, in the m id-winter periods of 1978 and 1979. Adult

emergence from outdoor flats of soil took place from mid-March to early

May, with most moths appearing during the f irs t four weeks of April.

P o tte r, H uber, and Watson (n .d .) determined heat un it accumulations

for these overw intering tobacco budworms. They suggested th a t physio­

logical processes associated with diapause were nearly complete by early

January . A fter th a t date a total accumulation of 173 centigrade heat

units (CHU) was required for emergence to occur. Early spring hosts

may play an im portant role in ca rry -o v er of Heliothis spp . to co tton ,

which requ ires an accumulation of 667 CHU afte r January 1 until f irs t

square (H uber, n .d . ) .

Knipling (1971) acknowledged th a t no precise data are available

on the actual num bers of moths th a t emerge in the sp ring in a given a rea .

Based on limited egg and larval records on host p la n ts , especially on

tobacco, and on lig h t-trap -c a tch data , Knipling has regarded 1,000 moths

6

per square mile as a reasonable estimate of the overw intering population

in typical ag ricu ltu ral a re a s .

Isely (1935); Brazzel e t al. (1953), Snow and Brazzel (1965), and

Lincoln e t al. (1967) found th a t in A rkansas, Louisiana, and no rtheastern

M ississippi, respectively , leguminous crops a re the major hosts of the

f ir s t generation of bollworms in the sp rin g . Corn is the im portant host

plant for the second generation in June and Ju ly . Snow and Brazzel

(1965) reported the occurrence of two generations on corn in M ississippi.

In early A ugust when corn is not longer a suitable host, th e th ird and

fou rth generations use cotton as the prim ary host. In the area around

College Station, T exas, oviposition on leguminous p lants and on corn

determ ines the bollworm infestation on cotton (Lopez 1976). In the Avra

Valley, Arizona, the lush growth of alfalfa during early sp ring and into

late May provides a food source fo r bollworms, which then move into corn

and cotton (Fye 1975).

In co n tra s t, the tobacco budworm appears to rely most heavily on

wild hosts early in the growing season (Neunzig 1963). F irst-genera tion

eggs and larvae a re found on a varie ty of fru iting p lan ts , as previously

d iscussed . Eggs are f ir s t found in April in cen tral Texa, cen tral Missis­

sippi and southern A rkansas; th e re a fte r , larvae a re continuously p resen t

through O ctober (Lincoln 1972).

Tobacco is the favored host fo r the second and la te r generations

of H. v irescen s. In the absence of tobacco, cotton is the principal sum­

mer host (Lincoln 1972). For a discussion of the relative seasonal abun­

dance of Heliothis on cotton in the Southw est, see Quaintance and B rues

7

(1905), Brazzel and Newton (1963), Sundman and Hanna (1963), and

Henry and Adkisson (1965).

H ost-plant Selection

The term "host-p lan t specificity" re fe rs to the range of p lant

species on which a given insect is known to occur in na tu re . "H ost-plant

selection" is the behavioral sequence by which an in sect d istinguishes

between host and nonhost p lan ts. A th ird term , "host-p lan t p reference ,"

is used to describe an in sec t's predilection to select some plants in p re f­

erence to o thers within its host-p lan t range (Maxwell and Jennings 1980).

H ost-plant selection is im portant when considering the population

dynamics of lepidopterous species. Because immature stages of Heliothis

have somewhat res tric ted mobility, eggs must be oviposited by female

moths on or near suitable hosts to ensure surv ival. Beck (1974) sta ted

tha t a t the behavioral level, the g rea tes t proportion of host-p lan t speci­

ficity is a function of the ovipositing females. T hus, an understand ing

of the oviposition process of Heliothis spp . is of prime concern in studying

the population dynamics and host selection of these species.

Specific stimuli th a t errianate from host p lan ts and release ovi-

positional responses are numerous and are im portant factors in determ in­

ing host specificity (de Wilde and de Loof 1973). Odors emanating from

rapidly growing cotton p lan ts have been reported to be a ttrac tive to H.

zea moths and to stimulate oviposition. F letcher (1929) a ttrib u ted the

attraction of bollworm moths to cotton p lan ts to increased nectar secretion .

Thomas and Dunnam (1931) showed th a t bollworm infestations do not al­

ways develop when th ere is an abundance of nectar; in stead , adult

8

9

H. zea moths show a s trong preference for succulent, lush p lan t grow th.

Gaines (1932) and F letcher (1941) also found th a t odors from rank-grow ing

cotton p lants appear to be im portant fac to rs influencing infestation .

Available food before o r during oviposition may enhance a ttra c ­

tiveness of certain p lants to the boll worm moth (Nutty combe 1930). How­

ever, Quaintance and B rues (1905) and Palmiter (1966) sta ted th a t moths

do not always oviposit on the same p lants on which they feed . Palmiter

hypothesized th a t the adu lt female H. zea may oviposit on a host species

selectively w ithout being influenced by the food source. Jerm y, Hanson,

and D ethier (1968) suggested th a t food p lant p reference of leipdopterous

larvae appears to be individually modifiable and related to previous ex­

perience. They observed such behavioral p lasticity in oligophagous

species such as the tobacco horn worm, Manduca sexta (L innaeus), as well

as in polyphagous species such as H. zea.

Chemical stimuli a re probably the a ttrac tive fac to rs among dif­

fe ren t p lan ts , b u t tactile perception of the p roper surface fo r oviposition

determ ines where the eggs are laid (Callahan 1957). Ditman and Cory

(1933) showed th a t the upper villous surface of corn leaves received 21.6%

of the to tal eggs of H. zea, w hereas the lower glabrous surface received

only 8.1%. L ukefahr, Noble, and Houghtaling (1966) showed no signifi­

cant difference between the number of eggs deposited on glanded and

glandless cotton s tra in s . The principal constituen t of these glands is

gossypol, which apparen tly did not influence oviposition. T heir study

did, however, show significantly fewer eggs laid on two stra in s of gla­

brous cotton. Gillham (1963) and S tadelbacher and Scales (1973) screened

a large num ber of cotton varie ties fo r oviposition preference and found

10

h irsu te cotton heavily favored by Heliothis spp . L ukefahr, Houghtaling,

and Graham (1974) found th a t a fte r five seasons of testing glabrous cot­

ton s tra in s in T exas, reduction in oviposition ranged from 36% in 1966 to

80% in 1969. Glabrous leaves provided an unsatisfactory surface fo r ovi­

position resu lting in few er eggs, fewer larvae, and fewer damaged

squares. Nicotiana p lants with 250 or more H. v irescens eggs had leaves

with many p ro trud ing tricornes and were v e ry villous, whereas p lan ts with

50 or fewer eggs had smooth leaf su rfaces (Greene and T hurston 1974).

Hillhouse and Piire (1976) determined the p refe rred oviposition sites of

H. zea and II. v irescens on soybeans; both species p re fe rred the more

pubescent lower leaf surface fo r egg deposition.

Host a ttrac tiveness is a complex phenomenon, and o ther factors

th a t have been reported to influence oviposition include th e fitn e ss of the

host (Adkisson 1958), number and acreages of host crops (Dicke 1939),

competition from o ther hosts (Lopez 1976), and phonological s ta te s of the

hosts (Isely 1935).

Johnson, S tinner, and Rabb (1975) studied the ovipositional

response of the boll worm to various phonological s ta tes of corn , tobacco,

and soybeans. Flowering stages of all the crops were the p re fe rred phon­

ological s ta te of oviposition. Comparisons made of the flowering stages of

the crops showed th a t the ovipositional response was g rea tes t on corn

and decreased successively fo r tobacco, soybeans, and cotton. When

G arza-B lanc and Mathieu (1972) planted co rn , sorghum , co tton , and

tomato in close proximity and sequenced for concurren t flowering, they

found an obvious bias of the bollworm for corn. Extensive studies have

also been conducted on the ovipositional p reference of a closely related

11

species, Heliothis arm igera Hubner, Parsons (1940) determined th a t ovi-

posltion was confined to the period of inflorescence in 23 species of sh o rt­

flowering crops and th a t the ovipositional relationship applied to the crop

as a whole, ra th e r than to single p lan ts .

Natural Enemies

Ecologists are giving much atten tion to understand ing causes for

observed fluctuations in insect population num bers. Yearly fluctuations

of Heliothis sp p . on major hosts are determined by a complex of factors in

addition to availability and a ttrac tiveness of food p lan ts; these include

climatic in teractions such as rainfall and cooling o r warming tre n d s , as

well as p red a to rs , p a rasites , and pathogens (Davis 1974).

Many beneficial species have a rep ressive effect on Heliothis

populations. Over 600 p reda to rs have been recorded in A rkansas cotton

fields (Whitcomb and Bell 1964); over 350 p reda to rs and parasites have

been estimated to occur in California cotton fields (van den Bosch and

Hagen 1966). Over 40 parasites of Heliothis have been reported (Muese-

beck and Krombein 1951; Stone e t al. 1965).

The composition of the p red a to r complex varies with location,

crop, and time of year. Genera such as Geocoris, N abis, O rius,

C hrysopa, Hippodamia, and Coleomegilla contain species th a t a re of major

importance in regulating Heliothis populations (Ridgway e t al. 1967).

Spiders (Araneida) (Whitcomb 1967a, 1967b) and an ts (Formicidae) and

certain wasps (Vespidae) (Whitcomb 1967a, 1967b; Lincoln e t 'a l . 1967)

may be im portant in reducing Heliothis populations. For a more complete

12

listing of p redato rs of Heliothis spp . see F letcher and Thomas (1943),

Whitcomb and Bell (1964), and L ingren, Ridgway, and Jones (1968).

The num ber of parasitoid species th a t a ttack Heliothis is much

more limited because parasito ids have a more specific host range than

p reda to rs. Parasites of Heliothis spp . a re usually most active in early

summer or late fall (Lewis and Brazzel 1968; Graham et al. 1972;

Harding 1976). In the la s t 50 years su rveys have been conducted in

various areas of the United S tates to identify parasito ids associated with

Heliothis species.

Chamberlin and Tenhet (1926b) observed the effectiveness of the

parasitoid Cardiochiles n igriceps Vier in controlling H. v irescens on

tobacco in Florida and Georgia. Wene (1943), who worked with tobacco

budworm in Virginia, reported Sagaritis p rovancheri (Dalle Torre)

(=Campoletis a rgen tifrons) (Cresson) as an im portant parasitoid of H.

v irescen s . Grayson (1944) made a su rvey to determine the effectiveness

of these two p arasito id s, C . n igriceps and S. p rovancheri. He observed

a 28%-94% reduction of Heliothis larvae on tobacco when these parasito ids

were p resen t. Snow et al. (1966) and Neunzig (1963) found a varie ty of

parasitoids attacking Heliothis on wild hosts . In collections from Carolina

cranesbill. Geranium carolinianum , an early-season host. Snow e t a l.

(1966) reared out five species of hym enopterous parasito ids from H.

v irescen s, C. n ig ricep s, M icroplitis corceipes (C resson ), Apanetele

m arginiventris (C resso n ), H yposoter s p . , and Netelia sp . Only one

species, M. croceipes, was found parasitiz ing H. zea . Neunzig (1963)

reared the parasito ids Campoletis perd is tinc tu s (Vierick) and Netelia sp .

from H. zea larvae associated with toadflax (Linaria canadensis v a r.

13

texana and C. n igriceps from tobacco budworm larvae feeding on deer-

g rass , Rhesda s p . In Mississippi (Lewis and Brazzel 1968) and in North

Carolina (Neunzig 1969), the two braconids, M. croceipes and C. n ig ricep s,

were the predom inant larval parasito ids. In addition to these two species,

Roach (1975) found th a t Campoletis sonorensis (Cam.) and Campoletis

flavicincta (A sh.) parasitized Heliothis in most areas of the Pee Dee region

of South Carolina. The tachinid species, A rchytas marmoratus (T n s .)

and Lespesia aletia (R iley), were also listed as occasional parasito ids of

Heliothis la rv ae .

Graham et al. (1972) studied the incidence of parasitism in the

Lower Rio Grande Valley, T exas. On larvae collected from March to

September on th ree species of wild p la n ts , Nicotlana rep an d a . Verbena

neomexlcana, and Ruellia runyonii, Graham e t al. found Completis spp . to

be the most common parasito ids. In to ta l, 6 d ip teran and 13 hym enopteran

species were recorded . B utler (1958a, 1958b) made extensive field collec­

tions of lepidopterous larvae from cotton, alfalfa, co rn , sorghum , and

desert weeds in Arizona. He found Eucelatoria arm igera (Coquillett) and

M. croceipes to be the most numerous parasito ids of Heliothis. O ther

species included C. tex a n u s , Lespesia archippivora (Riley) , and Chaeto-

gaedia sp . Werner (1978) listed the following species as associated with

H. v irescens in Arizona; C. n ig ricep s, Ap an teles m arginventris (C resso n ),

M. croceipes, and Campoletis flavicincta sonorensis.

Some parasito ids such as Trichogramma s p . and C . texanus attack

Heliothis eggs (Muesebeck and Krombein 1951). O ther genera such as

A panteles, Campoletis, and to some ex ten t Microplitis a ttack mostly early

in s ta r larvae, whereas C ardjochiles, Eucelatorla, and Lespesia tend to

p re fe r la rg e r, la te r 'in s ta r larvae (Ridgway and L ingren 1972).

Host p lants fo r a num ber of crop pests in Arizona and th e ir

associated predato rs and parasito ids have been discussed by Fye (1972,

1975). A large segm ent of the insect population in sou thern Arizona

overw inters on London rocket. Sisymbrium irio . As the London rocket

m atures, the in sects move to d e se rt plants th a t grow when w inter rains

are adequate (Fye 1975). The foremost host in some d esert areas is

d ese rt mallow, Sphaeralcea spp . (Stoner 1972); however, o ther d e se rt

plants are reservo irs of both beneficial and pest species. Knowledge

about the d istribu tion of Heliothis spp . on such hosts is im portant to

an understand ing of the ir long-term population dynamics in central

Arizona.

MATERIALS AND METHODS

Surveys for a lternate host p lants of Heliothls sp p . were made

from F ebruary until June in 1979 and 1980. Most of the acreage checked

was in Pinal County, Arizona, within a 25-mile radius of the City of

Coolidge. Major crops grown in th is area include su g arb ee ts , alfalfa,

and lettuce in the w inter and alfalfa, cotton, and corn in the summer.

In 1979 one area in Maricopa C ounty, the Kelly rose farm near Sun C ity,

was checked periodically in late w inter and early sp ring for Heliothis.

These resu lts were omitted because of inconsistent sampling times.

Heliothis larval populations developing on uniform stands of

sp ring hosts were sampled with a 39.1-cm insect sw eep-net. With plant

species not growing in dense s ta n d s , examinations of en tire p lants were

made to locate eggs and larvae. A fter Heliothis sp p . were found associ­

ated with a pa rticu lar p lant species in a given area , samples were taken

at the site at weekly and bi-weekly in tervals until the p lants reached

senescence or until no more eggs and larvae were found. Usually only

fru iting forms of potential host-p lan t species were checked for Heliothis.

The number of sweep samples and number of p lants examined to establish

approximate population densities varied between collection dates and lo­

cations because of such factors as manpower, host availability, and

infestation level.

Eggs and larvae found were taken back to the labora to ry , sepa­

rated from those of o ther species, and placed individually in 31-g, clear,

plastic cups approxim ately tw o-th irds full of a modified lima bean-agar

15

diet (Patana 1969). Samples were held in the laboratory a t 25°C under

naturally occurring day lengths for identification and parasite emergence.

H. zea and H. v irescens larvae were separated under magnifica­

tion by the characteristics listed by Boyer, Burleigh, and Wall (1977) and

Brazzel e t al. (1953). Using only the presence or absence of a mandibu­

lar retinaculum as a method of identification, as shown in Figure 1,

Heliothis larvae were difficult or impossible to identify until they reached

the th ird in s ta r . The most reliable characteristic for identification was

the presence of microspines on the e ighth abdominal (dorsal) tubercle of

the budworm and their, absence in the bollworm, as shown in Figures 2

and 3, respectively . Both charac teristics were used when necessary .

Heliothis phloxiphaga (Grote and Robinson) larvae were d istinguished from

H. zea by descrip tions given by Hardwick (1965) and by emergence of

adult m oths. Eggs of jH. v irescens and H. zea were distinguished by the

condition of the micropyle (Phillips 1978). Collections of damaged eggs

and of larvae th a t died as f irs t o r early second in s ta r o r th a t were too

damaged to identify were omitted from the re su lts .

Records were kept of p lant species, collection d a te s , Heliothis

s p p . , and larval in s ta r as well as parasito ids, disease, pupation, and

diapause of collected larvae. Parasitoids em erging from all collected

larvae were pinned and la te r identified by Dr. Floyd W erner, Departm ent

of Entomology, The U niversity of Arizona. Plant specimens were iden ti­

fied by individuals from the U niversity of Arizona Herbarium.

Between May 13 and May 27, 1980, unit area samples were taken

of Heliothis larval populations developing on redstem filaree, Erodium

16

cicutarium . This p rocedure consisted of m easuring and marking an

17

Figure 1. In n er surface of la te -in s ta r larvae of tobacco budworm (left) showing prominent retinaculum and of bollworm (right) showing concave inner surface without the retinaculum

18

Figure 2. Lateral view of abdominal segment eight of la te -in s ta r tobacco budworm larva showing d istinc t microspines on the tubercle

Figure 3. Lateral view of abdominal segment eight of late-instar cotton bollworm larva showing tubercle without microspines

0.5-m2 circu lar area in a uniform stand of the p la n ts , carefully clipping

the p lants a t ground level, placing them in a plastic bag , and bring ing

the sample back to the laboratory to check for eggs and larvae.

A lis t of all p lants smapled in 1979 and 1980, num ber of sweeps

taken or num ber of p lants examined, and dates when samples were taken

is given in Appendices A and B. the percen t parasitism for each Helio-

th is species collected on each host as well as percen t pupation was com­

piled. Precipitation data fo r the fall, w inter, and sp ring of 1978-79 and

1979-80 were obtained from the National P ark Service a t Casa Grande

Ruins National Monument. Heat un it da ta for th is time period were sup­

plied by D r. Roger T . H uber, Departm ent of Entomology, The U niversity

of Arizona.

In the sp ring of 1980 tobacco budworm pheromone trap s were

placed in Pinal County by M. S. Tollefson, Extension P est Management

Specialist, The U niversity of Arizona, to monitor early season moth ac­

tiv ity . T rap design was the cone-75-50 type as described by H artstack ,

Witz, and Buck (1979). Pheromone wicks, which were obtained from

Zoecon Corporation, Palo Alto, California, contained v ire lu re in a 16:1

ratio of (Z -ll-hexadecenal to (Z) -9 -te tradecenal (Tumlinson e t al. 1975).

T hree trap s were in operation along irrigation ditches in Magma, Eloy,

and Coolidge, Arizona, and were checked weekly from April 7 until

June 15..

19

RESULTS

Rainfall Data

In the d esert Southw est, cultivated p lants depend en tire ly on

irrigation for the water requ ired in th e ir production. Noncultivated

p lan ts, how ever, occur sporadically , depending on the amount and p a t­

te rn of rainfall. For th is s tu d y , rainfall data for the fall, w inter, and

sp ring periods preceding the two Heliothis sampling periods were obtained

from the National Park Service, Casa Grande National Monument, to d e te r­

mine the association of fall and w inter rainfall with plant species occurring

the following sp rin g . These data are p resen ted in Table 1.

Table 1. Rainfall recorded at the Casa Grande Ruins National Monument, Casa G rande, Arizona, October th rough May, 1978-79and 1979-80

Rainfall (inches pe r m onth), Oct. th rough May

Month 1978-79 1979-80

October 1.62 0.21November 2.08 0.02December 3.68 0.09January 2.87 1.71February 0.38

^ 2.693.54

March 1.12April 0.05 0.17May 0.57 0.17

Total for 8 months 13.94 7.03

20

21

Field Samples, 1979

In the sp ring of 1979, Heliothis larvae were found as early as

April 16 on C oulter's globe mallow, Sphaeralcea coulter! (W ats.) G ray, in

two locations near F lorence, Arizona. Of a total of 36 larvae collected on

th is host between April 16 and May 1, 1981, 86.1% were bollworms and

13.9% were tobacco budworms. On April 24, sp ring populations reached

a level of 17 H. zea and 3 H. v irescens larvae in 400 sweeps on the above

host.

On May 7, 1979, Heliothis sp p . were found infesting redstem

filaree, Erodium cicutarium (L.) L 'H e r., along roadside areas near Magma,

Arizona. Larvae were collected on dense stands of th is plant species until _

June 12, 1979, at five locations in Pinal County: Magma, Florence, Pica-

cho. La Palma, and along the Pinal Pioneer Parkway. A total of 220 larvae

was collected with species composition as follows: 61.8% H. v irescens,

28.9% H. phloxiphaga, 3.1% H. zea, and 6.2% undeterm ined Heliothis sp p .

Spring populations on th is host p lant reached a peak on June 1, 1979;

400 sweeps yielded the following num bers of la rv a e : 26 H. v ire sce n s ,

8 H. phloxiphaga, and 3 H. zea.

Another p lan t species infested with Heliothis larvae du ring th is

same time period was daisy fleabane, Erigeron d iv erg en s. Sw eep-net

samples taken a t weekly in tervals near Coolidge and La Palma between

May 12 and June 21, 1979 yielded 524 larvae of which 99.4% were iden ti­

fied as H. phloxiphaga and 0.6% as H. v irescen s . On May 15, 1979, 100

sweeps collected 132 H. phloxiphaga larvae and 1 H. v irescens larva;

numbers decreased sharp ly a fte r th is date . T hese data are p resen ted in

Table 2.

22

Table 2. Species composition of Heliothis on th ree sp ring host p lants in Pinal County in 1979

No. of Larvae

Percent of Each Heliothis Species

Plant Species v irescens zea phloxiphaga undeterm ined

Sphaeralceacoulter! 36 13.9 86.1 0.0 0.0

Erodiumcicutarium 220 61.8 3,1 28.9 6.2

Erigerondivergens 524 0.6 0.0 99.4 0.0

Field Samples, 1980

In the sp ring of 1980, Heliothis larvae were p resen t on garbanzo

bean, Cicer arietinum L . , a t two locations near Eloy. Eight H. zea larvae

were collected on th is cultivated host between April 15 and May 1; how­

ever, between May 10 and May 29, 225 larvae were collected with the fol­

lowing species composition: 92.5% H. v ire sce n s , 3.1% H. zea , and 4.4%

unidentified Heliothis species. On May 22, 20 p lants were examined and 86

tobacco budworm larvae collected. Populations declined a fte r th a t date as

the p lants dried up .

In 1980, growth of Erodium cicutarium was limited, and only 51

larvae were collected between May 10 and June 5 from a single location

near Coolidge, Arizona. The following species percen tages were obtained:

15.7% 13. zea, 51.0% H. phloxiphaga, 25.5% II. v ire sce n s , and 7.8% unde­

term ined Heliothis species. Populations on th is host peaked on May 27;

100 sw eep-net samples were taken and eight H. phloxiphaga, e ight H.

v irescen s , and two H. zea larvae were iden tified .

23

Yellow b ird -o f-p a rad lse , Caesalpinnia gilliesli W all., proved to be

a suitable host for tobacco budworms in the late sp ring and early summer.

From May 27 until June 26, 171 larvae were collected on th is p lan t species

near Coolidge, and all were identified as H. v irescen s . On June 12, ap­

proximately 30 p lants were examined for Heliothis spp . and 85 tobacco

budworm larvae were collected (Table 3).

Table 3. Species composition of Heliothis on th re e sp ring and early summer host p lan ts in Pinal County in 1980

No. of Larvae

Percent of Each Heliothis Species

Plant Species v irescens zea phloxiphaga undeterm ined

Cicerarietinum 233 92.5 3.1 0.0 4.4

Erodiumcicutarium 51 25.5 15.7 51.0 7.8

Caesalpinniagilliesii 171 100.0 0.0 0.0 0.0

Miscellaneous Plants Sampled

Low numbers of Heliothis were found on le ttuce , Lactuca sa tiva L . ,

alfalfa, Medicago sa tiva L . , field bindweed. Convolvulus s p . , p ig n u t,

Hoffmanseggia densiflora B e n th ., and devils-claw, Proboscidea parv iflo ra

(Wooton) Woot. & S tandi. The following p lants were sampled rou tinely ,

i . e . , more than th ree dates at th ree o r more locations, with which no

Heliothis larvae were found associated: London rocket. Sisymbrium irio L . ,

little mallow, Malva parv iflora L . , lupine, Lupinus s p . , annual yellow

24

sweetclover, Melllotus indicus (L. ) , d esert senna. Cassia covesii G ray,

slimleaf b u r-sag e . Ambrosia confertiflora DC, small flower gau ra , Gaura

parviflora D oug l., tree tobacco, Nlcotiana glauca Graham, and pecan.

Carya illinoensis Koch.

P lant D escriptions

Sphaeralcea coulteri (W ats.) Gray

T here are 16 species of globe mallow native to Arizona, many of

which are difficult to d istingu ish . D esert mallow, S . cou lte ri, is an

annual found on sandy soils along roadsides, fields, and mesas from

January to May in Pinal, Maricopa, Pima, and Yuma Counties a t elevations

of 2,500 feet or lower (P arker 1972). The peak flowering period for

desert mallow is March 20 (McGinnies 1980).

Erodium cicutarium (L.) L 'H er.

T here are two species of Erodium in Arizona. E. cicutarium and

E. texanum . Red stem filaree , E. cicutarium , is an annual, w inter annual,

or biennial and is found in g rea t abundance on plains and mesas th rough ­

out the s ta te from F ebruary until Ju ly a t elevations up to 7,000 feet

(Parker 1972). The peak flowering period is March 30 fro areas near

Tucson and a week to 10 days earlie r fo r warmer regions west of Tuson

(McGinnies 1980).

Dense stands of th is p lan t species were sampled along roadsides

and field bo rders in cen tra l Arizona in 1979 and 1980. Flowers occur in

an umbrellalike c lu s te r a t the end of long stalks arising from the leaf axils;

the fru it is elongate and beaklike (Kearney and Peoples 1950). Feeding

by Heliothis spp . was confined to the t ig h t, cymose flower heads and

succulent fru its as shown in Figure 4; la rg e r larvae consumed en tire

fru iting s tru c tu re s and were never observed feeding on leaves.

Erigeron d ivergens T o rr. & Gray

Daisy fleabane, E. d iv erg en s, is a common herbaceous species

found throughout Arizona on d ry , rocky slopes and mesas and in open

pine woods from February to O ctober a t elevations of 1,000 to 9,000 feet

(Parker 1972). Many Erigeron species have a ttrac tiv e daisylike heads

with blue, lavender, or white rays (Kearney and Peoples 1950). In 1979,

this plant species was p resen t in abundance in d istu rbed d esert areas

and along roadsides near Coolidge. H. phloxiphaga larvae increased to

large numbers on th is host and were observed feeding on both flower

heads and stem s.

Cicer arietinum L.

Chickpea, or garbanzo bean, C. arietinum , is a cultivated p lan t

grown for its edible seeds. It is an annual, 1 to 2 feet ta ll, e rec t and

b ranched , with g landu lar-pubescen t leav es. Flower are solitary and

white with pods 0.75 to 1 inch long, usually with one or two seeds

(Bailey 1925). This crop is grown extensively in Mexico, bu t 1980 was

the f irs t year it was planted in Pinal C ounty, Arizona.

Samples were taken from two fields near Eloy. Oviposition

occurred on leaves, stem s, and pods. Small larvae fed on leaves and on

the ou ter surface of the pod; la rg e r larvae bored into the pod and con­

sumed the developing seeds.

25

26

27

Caesalpinnia gilliesii Wall.

Yellow b lrd -o f-p a rad ise , C. gilliesii, is an introduced p lant from

South America. I t is a sh rub up to 7 feet in height with yellow flowers

which begin blooming in late sp ring and continue until m id-June

(McGinnies 1980). The terminal racemes a re la rg e and showy and the

inflorescence densely glandular (Bailey 1925). This plant is grown in

Arizona as an ornamental in residential a reas. I t occasionally escapes

from cultivation and may be naturalized in Mohave, Gila, Maricopa,

Cochise, and Pima Counties (Kearney and Peoples 1950).

On C. gilliesii, H. v irescens eggs were located on unopened floral

buds; larvae fed on these as well as on opened flowers as shown in

Figure 5. Very few larvae were observed to feed on the g reen pods of

these p lan ts .

Proboscidea parviflora (Wooton)

Devils-claw, P. p a rv iflo ra , flowers from m id-June th rough

September and is common in Arizona along the Gila R iver (Kearney and

Peoples 1950). Plants are coarse , v isc id -pubescen t annual h e rb s , with

large , somewhat fleshy f ru it, ending in a long , incurved beak.

For th is su rv ey , p lants were sampled in cotton fields in the

Blackwater Farms area near Sacaton, Arizona. A few large larvae were

collected from the leaves of th is p lan t in June 1980 and were identified

as H. v iresceris.

Hoffmanseggia densiflora B enth.

These perennial, herbaceous p lants are found along roadsides

from Navajo to Mohave C ounty, south to Graham, Cochise, Pima, and

28

Figure 5. Tobacco budworm larva feeding on unopened flower of yellow b ird -o f-p a rad ise# Caesalpinnia gilliesii

29

Yuma Counties, a t elevations of 5,000 fee t o r lower. The inflorescence is

conspicuously glandular, and the flowers occur from April to Septem ber

(Parker 1972). S tands of II. denslflora were examined for Heliothis in

May 1980, and a few IL v irescens eggs were collected.

F igure 6 shows the seasonal sequence of these host plants iden­

tified in the su rv ey . Information about flowering seasons was found in

McGinnies (1980) and is based on 13 y ears of observations. Estimated

flowering peaks a re fo r d ese rt areas near Tucson and may be a week to

10 days earlier in warmer regions west of Tucson. Table 4 p resen ts an

a rb itra ry ra ting of II. v irescens host p lants recorded in the T-year s u r ­

vey and is based on number and size-of larvae collected.

Mortality on D ifferent Host P lants

A ccurate percentages of parasitism could not be determined be­

cause of high larval mortality resu lting from sw eep-net in ju ry and the

failure of Heliothis larvae to develop sufficiently for parasites to emerge

because of v ira l, fungal, and bacterial infections. However, the species

involved and th e ir relative im portance was determ ined.

The percentage of parasitism for Heliothis species on d ifferen t

host plants is shown in Tables 5 and 6. The most significant information

these tables provide is a comparison between levels of parasitism on the

d ifferen t host p lants utilized by H. v ire scen s . In 1979 and 1980, p a ra ­

sitism of tobacco budworms on E. cicutarium was 55.0% and 63.6%, respec­

tively . This con trasts with 0.7% parasitism on C. gilliesii and 16.7% on

C. arietinum in 1980.

I Cicer arietfnum ̂ ^ Proboscideo parviflora

I Caesolpinnia gilliesii ^

Erodium cicutarium |---------------------:-------1

Sphaeralcea coulferiI------------------------- 1

Gossipium hirsutumI-

I 10 20 30 10 20 30 10 20 30 K) 20 30 K) 20 30 10 20 30

MARCH APRIL MAY JUNE JULY AUGUST

Figure 6. Seasonal sequence of some plants found to be hosts of the tobacco budworm in Arizona

31

Table 4. Summary of Hellothis v irescens host p lants recorded during sp ring 1979 and 1980 su rveys in cen tra l Arizona

Host Eggs

Forms Found

L arvae3

Small Large Host Rating*3

Cultivated

Cicer arietinum X X X Good

Caesalpinnia gilliesii X X X Good

Rosa sp . X X X Good

Gossypium hirsutum X X X Good

Wild

Sphaeralcea coulter! X X X Fair

Convolvulus arvensis X Poor

Erodium cicutarium X X X Fair

Hoffmanseggia densiflora X X Poor

Proboscidea parviflora X Fair

Erigeron divergens X Poor

a. Small = up to th ird in s ta r; la rge = fo u rth , fifth in s ta rs .✓

b. Good = many large largfae, eggs; fair = eggs, small larvae; poor = a few small larvae, eggs.

32

Table 5. Relative parasitism of th ree Heliothis spp . on d ifferen t host p lants in central Arizona in 1979

Percent Parasitism 3

Plant Species H. zea H. v irescens H. phloxiphaga

Erodium cicutarium 5/12-6/12 0.0 (6) 55.0 (100) 34.9 (43)Sphaeralcea coulter! 4/24-5/1 5.0 (20) 0.0 (3) 0.0 (0)Lactuca sativa 4/12-4/19 0.0 (4) 0.0 (0) 0.0 (0)Medicago sativa 5/3 0.0 (1) 0.0 (0) 0.0 (0)Erigeron d ivergens 5/12-6/21 0.0 (0) 66.7 (3) 23.4 (32)

a. Number of larvae observed (in paren theses) does not include larvae th a t died from in jury or d isease.

Table 6. Relative parasitism of th ree Heliothis s p p . on d ifferen t host p lants in cen tral Arizona in 1980

Percent Parasitism a

Plant Species 11. zea H. v irescens 1}. phloxiphaga

Cicer arietinum 4/15-5/27 26.7 (15) 16.8 (1677) 0.0 (0)Erodium cicutarium 5/10-6/5 25.0 (8) 63.6 (11) 31.2 (16)Proboscidea

parviflora 6/18-6/26 0.0 (0) 16.7 (18) 0.0 (0)Caesalpinnia

gilliesii 5/27-6/26 0.0 (0) 0.7 (133) 0.0 (0)

a. Number of larvae observed (in paren theses) does not include larvae th a t died from in ju ry or disease.

33

In considering overall m ortality a ttrib u ted to bacteria , v iru s ,

fungi, in ju ry , and parasites , the number of larvae reaching the pupal

stage on each host is also compared in Table 7. Between May 12 and

June 12, 1979, 135 tobacco budworm larvae were collected on E. cicu-

tarium , with 33.3% reaching the pupal stage. In 1980, on th is same host, ,

only 13 H. v irescens larvae were collected between May 10 and June 5,

with 30.8% becoming pupae. On the hosts , Cicer arietinum and Caesal-

pinnia gilliesii, 209 and 171 larvae, respectively , were collected between

April 15 and May 27 on the form er and between May 17 and June 26 on

the la tte r species; pupation was 76.1% and 77.2%, respectively .

Daisy fleabane, Erigeron d iv erg en s, was an im portant spring

host fo r 11. phloxiphaga in 1979. This noctuid species has never been

recorded as a pest of cotton; however, i t was reported to a ttack tomatoes

in central California (Lange and M ichelbacher, 1937). Parasitism reached

moderate levels for larvae of th is species feeding on E. d iv erg en s; of

521 larvae collected, 23.4% were parasitized (Table 5) and 47.5% pupated

successfully as shown in Table 7. In 1979 and 1980, 65 and 26 11.

phloxiphaga larvae, respectively , were also collected on red stem filaree,

Erodium cicutarium , with 34.9% and 31.2% parasitism recorded, as shown

in Tables 5 and 6.

Common Parasitoid Species

Parasito ids common to H. v irescens and H . phloxiphaga collected

on Erodium cicutarium include the following species: Campoletis sonoren-

s is , Pristom erus sp inator (F .) , Hyposoter exiguae (V ierreck ), Lespesia

a rch ipp ivera , and Microplitis croceipes. Spilochalci sp . (sida group) and

34

Table 7. Relative abundance of Hellothis spp . larvae on d ifferen t sp ring host p lants in Pinal C ounty, Arizona

H. v irescens Larvae Collected

PupatingCollection % of Total ---------------------------

Host Plant Period Number Collected Number Percent

H. v irescens

1979

Sphaeralcea coulteri 4/16-4/21 5 3.4 NAConvolvulus arvensis 5/1 1 0.7 NAErodium cicutarium 5/12-6/12 135 93.8 45 33.3Erigeron divergens 5/12-5/22 3 2.1 1 33.3

1980

Erodium cicutarium 5/10-6/5 13 3.2 4 30.8Cicer arietinum 5/10-5/29 209 50.8 159 76.1Caesalpinnia gilliesii 5/17-6/26 171 41.6 132 77.2Proboscidea parv iflora 6/18-6/26

H.

18

zea

4.4 15 83.3

1979Sphaeralcea coulteri 4/16-5/1 31 59.6 20 76.9Convolvulus arvensis 5/1 5 9.6 NAErodium cicutarium 5/12-6/1 7 13.5 6 85.7Convolvulus tinc tu riu s 5/12 4 7.7 4 100.0Lactuca sativa 4/12-5/1 4 7.7 4 100.0Medicago sativa 5/3 1 1.9 1 100.0

1980Erodium cicutarium 5/10-5/27 8 34.8 6 75.0Cicer arietinum 4/15-5/13 15

H. phloxiphaga

65.2 10 66.7

1979'Erodium cicutarium 5/12-6/12 65 11.1 27 41.5Erigeron d ivergens 5/12-6/21 521 88.9 249 47.8

1980Erodium cicutarium 5/10-6/5 26 100.0 11 42.3

35

Rogas perp lexus Gaha, were found to emege only from tobacco budworm

larvae, whereas Cardiochiles seminger (Gresson) was res tric ted to H.

phloxlphaga on both red stem filaree and daisy fleabane.

Only th ree tobacco budworm larvae were collected from daisy

fleabane in 6 weeks of sampling, and from these , two parasitoid species,

P . sp inator and L. arch ipp ivora , em erged. H_. phloxlphaga larvae from

th is p lant yieleded the following parasito id species: L. a rch ipp ivo ra ,

Eucelatoria sp . (arm igera g ro u p ) , A rchytas m arm oratus, Chaetogaedia

s p . , M. croceipes, Cardiochiles sem iniger, Campoletis sonorensis, P .

sp in a to r, and Hyposoter ex iguae. These data a re p resen ted in Table 8.

In early sp ring of 1979, 31 H. zea larvae were collected from

Sphaeralcea coulter! and only 1 parasito id , Rogas p e rp lex u s, emerged;

from the plant host Erodium cicutarium , 7 bollworms were collected with

no parasitoid emergence. In 1980, 8 II. zea larvae were collected from

red stem filaree with two parasitized by Campoletis sonorensis. Cicer

arietinum was a host of H. zea from April 15 until May 22, 1980, with

22.7% parasitism by C. sonorensis! and Hyposoter ex iguae. These data

a re p resen ted in Tables 7 and 8.

H ost-plant Specificity

Table 9 shows the host p lants used by each Heliothis species in

1979 and 1980. II. v lrescens was found on e igh t d ifferen t p lant species

and H. zea , collected on seven hosts , was most abundan t in early sp ring

bu t decreased noticeably from samples taken a fte r late A pril. The species

H. Phloxlphaga was found on Erodium cicutarium and Erigeron d ivergens

in 1979. In 1980, E. d ivergens was absen t from the d esert landscape.

Table 8. Species of parasito ids found on Heliothis s p p . in central Arizona during the sp rings of 1979 and 1980

Parasitoid Heliothis spp . Host Plant

D iptera

Tachinidae

Lespesie archippivora v irescens. redstem filaree.phloxiphaga daisy fleabane,

devils-clawEucelatoria sp . phloxiphaga daisy fleabaneChaetogaedia sp . phloxiphaga daisy fleabane

Hymenoptera

Braconidae

Microplitis croceipes v ire scen s , redstem filaree .phloxiphaga daisy fleabane

Rogas perp lexus v ire sce n s , redstem filaree.zea C oulter's globe

mallowCardiochiles seminiger

Ichneumonidae

phloxiphaga redstem filaree, daisy fleabane

Campoletis sonorensis v irescens. redstem filaree.

Pristom erus sp inator

Hyposoter exiguae

zea,phloxiphaga

v ires cen s, phloxiphagav ire sce n s ,phloxiphaga,zea

daisy fleabane, b ird -o f-parad ise , devils-claw s, chickpearedstem filaree, daisy fleabaneredstem filaree, daisy fleabane, devils-claw s, chickpea

Chalcididae

virescens redstem filareeSpilochalcis sp.

Table 9. Host utilization by Heliothis s p p . on a given host p lant in the sp rings of 1979 and 1980 in central Arizona

37

Plant Species

Heliothis Species

H. v irescens H. zea H. phloxiphaga

Lactuca sativa XSphaeralcea coulteri X XConvolvulus arvensis XMedicago sativa XErodium cicutarium X X XCarthamus tinc tu riu s XCicer arietinum X XCaesalpinnia gilliesii XHoffmanseggia densiflora XProboscidea parv iflora XErigeron divergens XRosa sp . X X

in 1979. In 1980, E. divergens was absen t from the d esert landscape bu t

moderate numbers of H. phloxiphaga were found on Erodium cicutariiim .

Pheromone Monitor T raps

In Coolidge, 225 H. v irescens moths were cap tured between

April 26 and May 26, 1980. Peak trap catches in Eloy occurred from

May 12 until May 23; 137 moths were collected. In Magma, only 26 moths

were trapped between April 7 and June 15.- i :

38

Unit Area Samples

Between May 13 and May 27, 1980, un it area samples were taken

on five separa te occasions on Erodium cicutarium . No eggs o r larvae were

collected using th is technique.

DISCUSSION

It is im portant th a t data be available on all factors th a t could

influence Heliothis population dynam ics. This study, completed in the

early summer of 1980, provides insigh t into the role of a lternate host

p lants in early-season activ ity of Heliothis species in Arizona. Such

information is necessary for in telligent management of Heliothis s p p .

Weather is the dominant factor influencing all components of the

life system of Heliothis spp . The d irect effects of its variable elements

(tem perature, m oisture, e tc .) on Heliothis a lte r not only behavior but

also ra te s of development, fecund ity , and survival of these p e s ts . The

effects of w eather on host plants and natu ra l enemies also regulate th e ir

synchrony with and impact on Heliothis spp . (S tinner, Rabb, and

Bradley 1977).

D esert regions have an environm ent characterized by low m oisture,

which is irregu larly d istribu ted in space and time, and d esert p lants have

a phenology closely related to rainfall and tem p era tu re , and , in p a rticu la r,

to soil m oisture (Ackerman and Bamberg 1974). The amount of moisture

in the soil at the s ta r t of the sp ring growth period determ ines initial

flowering response (McGinnies 1980; Ackerman and Bamberg 1974). Cli­

matic information obtained from the Casa Grande Ruins National Monument

indicates th a t rainfall accumulation from October to December, 1978, was

7.38 inches, as shown in Table 1; flowering was exceptional for many

d esert p lants the following sp rin g . In 1979, rainfall du ring these same

th ree months was only 0.32 inch; flowering d ese rt p lants were scarce in

39

40

the sp ring of 1980. In the lower Sonoran d e se rt, ra infall-tem perature

combinations th a t produce good ea rly -sp rin g flowering seasons may occur

only once every 10 years and once every 30 to 40 years to produce an

exceptional early -sp rin g flowering display (McGinnies 1980). Wild hosts

in d ese rt regions appear to be an unpredictable food source for Heliothis

spp .

Among the d esert p lants found in great abundance in the sp ring

of 1979 were C oulter's globe mallow and redstem filaree. Sphaeralcea

coulteri se rves as a host of Heliothis zea before alfalfa and corn are

available. H. v irescens larvae were collected on redstem filaree at a

la ter date than H. zea larvae and were p resen t until th e end of May on

th is host. Henry and Adkisson (1965) reported th a t tobacco bud worm

infestations developed la te r than did bollworm in festa tions. Emergence

of bollworms from diapause is 2 to 3 weeks earlier than th a t of tobacco

budworms in Brownsville, Texas (Fife and Graham 1966).

In 1980, growth of native d e se rt p lants was limited to moist areas

such as canal banks. Heliothis populations were not p resen t in signifi­

cant num bers on any wild host. Large numbers of larvae were collected

from two fields of garbanzo beans and also from yellow b ird -o f-parad ise .

On the host, Cicer arietinum ,a large percentage of larvae collected be­

tween April 15 and May 1 was bollworms; between May 10 and May 29

most larvae collected from th is host were H. v irescen s . All larvae col­

lected on Caesalpinnia gilliesii were tobacco budworms.

The climatic situation in cen tral Arizona is similar to th a t found

in the Presidio a rea of Texas where because of d e se rt ecology, suitable

host p lants for the bollworm and tobacco budworm are confined prim arily

to the Rio Grande Valley. C otton , alfalfa, and a small acreage of o ther

cultivated crops are the prim ary host p lants (Cole, Adkisson, and Fye

1973).

The kinds (host plant species and phenological sta tes) and

quantity (biomass and acreage) of food vary from area to a rea , year to

year, and seasonally. An early -season key host such as yellow b ird -o f-

paradise may be of no significance in late season and visa v e rsa . Sea­

sonal production of moths depends on a complex of hosts th rough which

Heliothis biomass flows from sp rin g to fall.

Spring emergence of Heliothis s p p . in cen tra l Arizona occurs

approxim ately 1.5 months before cotton begins squaring . Diapausing H.

v irescens begin sp ring emergence a t 139 CHU and complete it a t 417 CHU

(Potter e t al. n .d . ) . In agreem ent with these heat unit values, emergence

in 1979 began March 7 and was completed by May 2. In 1980, activ ity

began February 13 and ended by April 18. These dates are based on

heat-un it accumulations determined by P o tter e t al. ( n .d . ) .

In 1979, most Gossypium hirsutum in Pinal County was planted

between March 11 and May 1 and in 1980 between March 1 and mid-April

(Tollefson, 1980, personal communication). Based on hea t-un it accumu­

lations for cotton, as determined by Huber ( n .d . ) , f ir s t square produc­

tion in these years occurred in early Ju ly and late Ju n e , respectively .

The thermal requirem ent for cotton to square is 389 CHU from planting

date .

Seasonal activ ity of Heliothis sp p . extends over a longer period

than does the growing season of any single species of host p lant.

Sphaeralcea coulter!, Erodium cicutarium , Cicer arietinum , Caesalpinnia

41

42

gilliesii, and Proboscidea parv iflora provide a food source for Heliothis

larvae at a time when cotton is unavailable, and , in tu rn , these larvae

serve as hosts for the buildup of parasitoid species th a t a ttack la te r

generations of Heliothis species on summer crop p lan ts.

Populations of Heliothis spp . on these d ifferen t hosts v a ry in

surv ival ra tes due to nutritional and microenvironmental d ifferences

Mortality from natural enemies is also influenced by factors in trin sic to

host p lan ts . Erodium cicutarium provides an excellent m icrohabitat for

parasito ids of Heliothis spp . In 1979 and 1980, eight parasito id species

were identified (Table 9). The closed-canopy growth charac teristic of

redstem filaree appears to a ttra c t parasito ids and apparen tly acts as a

buffer against harsh environm ental conditions. The fru iting s tru c tu re s

of th is plant fed on by Heliothis larvae facilitate a ttack by parasito ids

(Figure 4). On the host Caesalpinnia gilliesii, only one parasito id ,

Campoletis sonorensis , emerged from 171 H. v irescens larvae collected.

Collections were made in late May and early June when warmer tem pera­

tu res may cause parasitoid populations to decline. On Cicer arietinum

only two parasito ids, Campoletis sonorensis and Hyposoter exiguae,

emerged from 233 collected la rv a e . Garbanzo bean p lants are exposed

to su n , ra in , and high tem peratures under field conditions and are

therefo re not v e ry a ttrac tiv e to parasito ids. Larvae penetra ting the pod

of th is p lan t and feeding on developing seeds are physically pro tected

from attack by most parasito ids species.

The effects of each natural enemy species d iffer m arkedly accord­

ing to the host plant species and its phenological sta te (S tinner e t al.

1977). Examples of th is are tach in id , ichneumonid, and braconid species

43

which commonly take a heavy toll of H. zea on tobacco (Irabagon 1973)

and cotton and soybeans (Hughes 1975) bu t have little effect on larvae

feeding within pro tective corn husks (Hughes and Rabb 1976).

The p lant species Erigeron d iv erg en s , even though only an inci­

dental host of H. v ire scen s , was im portant in supporting large numbers

of Heliothis phloxiphaga larvae. From these larvae emerged many para-

si toids common to both H. v irescens and H. zea, which probably built up

to high num bers on Erigeron d ivergens and Erodium cicutarium and then

moved to cotton to a ttack la ter generations of II. zea and H_. v irescen s .

The percentages of parasitism shown in Tables 5 and 6 are an

indication of the ability of parasito ids to locate the ir hosts. Numbers

given are relative because 10% to 40% of the larvae generally succumbed

to bacterial, fungal, and v iral infections before they were large enough

for parasitoid emergence. These larvae were excluded from the calcu­

lations for percen t parasitism given in Tables 5 and 6. Parasitism was

still high; it averaged 22.1% for all tobacco budworm larvae collected in

1979 and 1980.

The tru e measure of the importance of a host p lant in the buildup

of an insect population is not the num bers of larvae infesting the host,

bu t the numbers of adu lts produced p e r unit area of the host and the

abundance of the host p lant in the agroecosystem (Stadelbacher 1979).

However, in all rep o rts except th a t of Graham and Robertson (1970), the

identification of early -season hosts was based on the num bers of larvae

collected. Similar criticism can be made of th is s tu d y . The d istribu tion

of the F i larval population th roughout an agroecocystem and the density

of the larval populations on various hosts at any given time are determined

44

by the selection of specific hosts by the ovipositing female moths and the

d istribution and abundance of the host. As the season p ro g resses , the

species composition of the plant complex as well as the stage of develop­

ment of each p lant species varies according to the normal phenology of

the individual species (Stadelbacher 1980).

In the Arizona d e se rt, d istribu tion of Heliothis species on wild

host p lants is not uniform and is difficult to estimate accurately because

the hosts are so widely scattered and are a ttrac tive to ovipositing moths

for such a sho rt period of time. Populations are also extremely variable

from year to year; therefo re , it is difficult to assess the role these

plants play in Heliothis population dynamics.

H. v irescens appears unlikely to increase greatly on wild hosts

because of the inconsistency of the rainfall essential to p lant growth and

also due to high larval m ortaility. P lants such as yellow b ird -o f-parad ise

are more perm anent food sources and may produce a large percentage of

the adult population th a t m igrates to cotton and produces the initial larval

infestations on cotton in Arizona. Cage studies a re needed to calculate

actual num bers of moths emerging from each host listed to determine its

tru e importance.

Pheromone trap -ca tch records provided by Tollegson (1980, p e r­

sonal communication) indicated th a t large num bers of F2- and Fa-

generation moths emerged in the sp ring of 1980 near Eloy and Coolidge,

Arizona, from areas where ornamental plants were relatively abundan t.

In Peoria, Arizona, a severa l-acre n u rse ry field of roses produced large

num bers of Heliothis, which moved into adjacent cotton fields (Sluss and

45

Graham 1979). In C entral Arizona, ornamental p lants may be very impor­

tan t in the early-season dynamics of Heliothis species.

Henry and Adkisson (1965), working in cen tra l T ex as, and

L aster and F u rr (1971), working in M ississippi, suggested th a t stub

cotton may be im portant in sustain ing populations of overw intering Helio­

th is in these a reas. During the w inter of 1979-80, approxim ately 60,000

acres of stub cotton were cultivated in Arizona (Taylor and Hathorn 1981).

This cotton fru its 3 to 4 weeks earlie r than planted cotton and essentially

fills the host plant gap between early June and early Ju ly when planted

cotton begins to square . F u rth e r research is needed to determine the

size of Heliothis populations in these ratoon fields. Taylor and Hathorn

(1981) observed large populations of p reda to rs and parasites in stub

fields and low num bers of bollworm-budworm damaged term inals. These

beneficials may la te r move to planted cotton.

Knipling (1966) proposed th a t Heliothis spp . might be controlled

over a region by releases of ste rile in sects or th rough the in teraction of

sterile insects with p reda to r and parasitoid releases. S terile in sect re ­

leases should be most successful when populations a re low, when females

a ttrac t the la rg e s t number of males, and when the incidence and f re ­

quency of mating is low (Stadelbacher, L aste r, and Pfrimmer 1972). Moth

populations in early sp rin g , originating from su rv ivo rs of diapausing

pupae, a re p resen t in low num bers. For example, Blanchard (1942) esti­

mated 99% w inter mortality of H. zea during 1941, and Phillips and B arber

(1929) reported an average of 95% w inter m ortality. S tadelbacher and

Martin (1980) reported th a t 87.3% of the larvae of tobacco budworms caged

46

in the fall of 1976 and 60.05% of those caged in the fall of 1977 died before

emergence.

To obtain the ratio of sterile to fertile male moths requ ired to

supp ress a population, one must determine moth density on each major

host p lant species a t a given time for a given acreage p rio r to release.

However, in Arizona the information needed to fully understand Heliothis

spp . dynamics is still incomplete. Population models th a t take into ac­

count species biology and seasonal occurrence and abundance of host

p lants along with densities of Heliothis populations per un it a rea are

needed. These a re the critical param eters in developing any successful

sterile in sect release and biological control program s.

Population suppression with released parasito ids o r disease may

not be feasible on wild host p lants in Arizona because acreages are so

variable from year to y ear. B lanketing the en tire d ese rt with enough

parasito ids and disease to control Heliothis populations in the sp ring

would be an enormous task and is not cu rren tly justified due to the cost

of the microbial agen ts and lack of rearing facilities fo r the parasito ids.

However, if populations increase on ornam entals and cultivated p lan ts as

suspected , a control program th a t involves the use of favorable hosts

such as Cicer arietinum and Caesalplnnia gilliesil as trap crops might be

successful in destroy ing a large percen tage of the and F2 generations.

This method could lower the level of subsequent Heliothis populations on

cotton.

SUMMARY

Data from two years of collection show the abundance in the >. 1

sp ring of fru iting ornamental p lants such as Caesalpinnia gilliesii as well

as cultivated c rops, i . e . , Clcer arietinum , are probably of considerable

importance to the buildup of populations of Heliothis spp . in central

Arizona before cotton is available as a host. D esert p lants such as

Sphaeralcea coulter! and Erodium cicutarium are variable in th e ir abun­

dance due to inconsistent rainfall; these hosts also seem to suppo rt a

large natural enemy complex th a t regu lates the buildup of large numbers

of Heliothis larvae. T hus, these p lants seem to play a minor role in

Heliothis population dynamics. However, fu r th e r studies should be

made to establish more definitely the role of each of these hosts in af­

fecting Heliothis s p p . abundance.

47

APPENDIX A

PLANT SPECIES SAMPLED FOR HELIOTHIS SPP.IN 1979

Family

Compositae

Convolvulaceae

C ruciferae

Geraniaceae

SampleGenus and --------------------------------- — g-

Species Common Name Date Size3 Location0

Erigerondivergens

Helianthusannus

Lactucasativa

Convolvulussp .

Sisymbriumirio

Erodiumcicutarium

daisy fleabane

commonsunflower

lettuce

field bindweed

London rocket

redstem filaree

5/12 1005/15 1005/15 505/22 505/22 1005/22 505/29 505/29 1006/6 1006/6 506/12 1006/21 50

4/17 205/1 255/22 75

4/12 254/19 254/19 205/1 20

5/1 205/12 505/22 50

1/18 4003/15 400

4/16 204/21 205/1 205/12 6005/12 75

(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e(s) e

(p) b(P) b(s) e

(P) f(P) f(p) c(P) b

(a) b(p) e(p) e

(s) a(s) a

(s) b(s) b(s) b(s) b(s) b

48

49

FamilyGenus and

Species

Sample

Date Size3 Location ̂

Geraniaceae Erodium red stem filaree 5/15 70 (s) bcicutarium 5/15 215 (s) d(co n .) 5/22 100 (s) b

5/22 50 (s) d5/22 20 (s) e5/22 100 (s) g5/29 100 (s) b ’6/1 400 (s) g6/6 400 (s) g

' 6/6 200 (s) b6/6 25 (s) e6/12 100 (s) b6/12 100 (s) g6/21 50 (s) b6/21 50 (s) g

Leguminosae Lupinus sp . lupine sp . 4/17 50 (s) b4/17 50 (s) d

Medicago alfalfa 5/3 30 (s) fsativa

Malvaceae Malva little mallow 4/3 500 (s) bparviflora 4/17 200 (s) b

Sphaeralcea C oulter's 4/16 10 (s) bcoulteri • globe mallow 4/17 200 (s) b

4/19 10 (s) c4/21 10 (s) b4/24 400 (s) b5/1 500 (s) d5/1 400 (s) b

Rosaceae Rosa sp . cultivated roses 4/19 200 (p) c4/26 400 (p) c5/17 250 (p) c5/29 75 (p) c6/12 100 (p) c

a. (s) = sw eep-net samples; (p) = plant samples.b . Approximate locations: a = Casa G rande; b = Magma; c = Peoria;

d = Florence; e = La Palma; f = Yuma; g = Picacho.

APPENDIX B

PLANT SPECIES SAMPLED FOR HELIOTHIS SPP.IN 1980

Family

SampleGenus and ------------------ =------------------- g

Species Common Name Date S izea LocationD

C ruciferae Sisymbrium London rocket 2/28 100 ( s ) airio 2/28 100 (s) b

Geraniaceae Erodium Redstem filaree 2/28 100 ( s ) bcicutarium 2/28 50 (s) d

2/28 150 (s) c3/12 100 ( S ) c3/25 50 ( S ) d5/10 200 (s) e5/13 100 ( s ) e5/13 40 (p) e5/22 100 (S ) e5/27 100 ( s ) e5/29 100 ( s ) e6/5 100 ( s ) e

Leguminosae Caesalpinnia yellow b ird -o f- 5/27 5 (p) fgilliesii paradise 6/5 5 (p) f

6/12 50 (p) f6/12 5 (p) f6/20 30 (p) f6/26 5 (p) f

Cicer garbanzo bean 4/15 20 (p) garietinum 4/26 20 (p) a

5/1 20 (p) a5/10 20 (p) g5/10 20 (p) a5/13 75 (p) a5/22 20 (p) a5/27 20 (p) a5/29 20 (p) g

Hoffamanseggia hog potato 5/29 30 (p) edensiflora 6/5 30 (p) e

50

51

FamilyGenus and

Species Common Name

Sample

Date S ize3 Location ^

Leguminosae Medicago alfalfa 5/10 100 (s) f(co n .) sativa 5/10 100 (s) e

5/13 100 (s) e5/13 100 (s) e5/13 100 (s) f5/22 100 (s) e5/22 100 (s) g5/27 100 (s) e5/27 100 (s) e6/5 100 (s) e

Melilotus annual yellow 3/28 100 (s) bindicus sweetclover 3/25 100 (s) b

3/25 50 (s) d

Malvaceae Malva little mallow 2/28 50 (s) bparviflora

Sphaeralcea globe mallow 2/28 50 (s) bsp . 3/12 100 (s) c

Martyniaceae Proboscidea devils-claw 6/18 10 (p) hparviflora 7/1 5 (p) h

a. (s) = sw eep-net samples; (p) = p lan t samples.

b . Approximate locations: a = La Palma; b = Magma; c = Marana; d = Picacho; e = Florence; f = Coolidge; g = Eloy; h = Blackwater.

REFERENCES

Ackerman, T . L . , arid S. A. Bamberg. 1974. Phonological studies in the Mohave d esert a t Rock Valley (Nevada T est S ite), p . 215-226.In H. L ieth, ed ito r. Phenology and Seasonality Modeling. SJpringer-Verlag, New York, 444 p .

Adkisson, P. L. 1958. The influence of fertilizer applications on popula­tions of Hellothis zea and certain insect p red a to rs . J . Econ. Entomol. 51: 757-59.

Bailey, L. H. 1925. Manual of Cultivated P lants. Macmillan C o ., New York. ,851 p .

B arber, G. W. 1937. Seasonal availability of food p lants of two species of Heliothis in easte rn Georgia. J . Econ. Entomol. 30: 150-58.

B atra , W. W. 1979. Insects associated with weeds in the no rtheastern United S ta tes: quickw eeds, Galinsago ciliata and G. parviflora (Compositae). Environ. Entomol. 8:1078-82.

Beck, S. D. 1974. Theoretical aspects of host p lant specificity in in ­sec ts , p . 290-311. In F. G. Maxwell and F. A. H arris , ed ito rs, Proc. Summer In s t . "Bio. Cont. P lan ts , In sec ts , and D iseases. U niversity P re ss , M ississippi, 647 p .

B lanchard, R. A. 1942. Hibernation of the corn earworm in the central and no rtheastern p a rts of the United S ta tes. USDA Tech. Bull. 838.

Boyer, W. P . , J . G. B urleigh, and M. L. Wall. 1977. Larval charac te r­istics for separating bollworm and tobacco budworm. Ann.Entomol. Soc. Amer. 70: 5-6.

Brazzel, J . R . , L. D. Newsom, J . S. Roussel, C. Lincoln, H. D. Williams, and G. B arnes. 1953. Bollworm and tobacco budworm as cotton pests in Louisiana and A rkansas. Louisiana Tech. Bull. 482: 1-47.

Brazzel, J . R . , and W. Newton, 1963. Seasonal incidence of tobacco budworms on cotton in Texas in 1962. Texas A gr. Exp. S ta.P rog. Rep. 2272.

B utler, G. D. 1958a. Braconid wasps reared from lepidopterous larvae in Arizona in 1957. Pan-Pacific Entomol. 34: 221-23.

B utler, G. D. 1958b. Tachinid flies reared from lepidopterous larvae in Arizona. J . Econ. Entomol. 51: 561-62.

52

53

Callahan, P. S. 1957. Oviposition response of the corn earworm to dif­ferences in surface tex tu re . J . Kansas Entomol. Soc. 30: 59-63.

Chamberlin, F. S . , and J . N. T enhet. 1926a. The seasonal h isto ry and food habits of the tobacco budworm, Heliothis v irescen s , in the southern tobacco growing region. J . Econ. Entomol. 19:611-14.

Chamberlin, F. S . , and J . N. T enhet. 1926b. Cardiochiles n ig riceps, and im portant parasite of the tobacco budworm, H. v ire scen s .J . A gr. Res. 33: 21-27.

C lark, L. R . , P . W. G eier, R. D. H ughes, and R. F. M orris. 1967. The Ecology of In sect Populations in Theory and Practice. Metheren and C o ., L td ., London. 232 p .

Cole, C. L . , P. L. Adkisson, and R. E. Fye. 1973. Seasonal abundance of Heliothis larvae on cotton in the Presidio , Texas a rea . J .Econ. Entomol. 66: 524-26.

Crow der, L. A ., M. S. Tollefson, and T . F. Watson. 1979. Dosage-m ortality stud ies of syn thetic py re th ro ids and methyl parathion on the tobacco budworm in cen tra l Arizona. J . Econ. Entomol.72: 1-3.

Davis, F. M. 1974. The life system concept as a guide to understand ing population dynamics, p . 62-68, In F. G. Maxwell and F. A. H arris , ed ito rs, Proc. Summer In s t. Bio. Cont. P lan ts, In sects , and.D iseases. U niversity P ress , M ississippi, 647 p.

de Wilde, J . , and A. de Loof. 1973. Reproduction-endocrine control, Vol. 1. In M. Rockstein, ed ito r. The Physiology of Insecta . A cadem icT ress, New York.

Dicke, F. F. 1939. The seasonal abundance of the corn earworm. J . A gr. Res. 59: 237-58.

Ditman, L. P . , and E. N. Cory. 1933. Corn earworm stud ies . U niver­sity of Maryland A gr. Exp. S ta . Bull. 348: 525-43.

Fife, L. C . , and H. M. Graham. 1966. Cultural control of overw intering bollworm and tobacco budworm. J . Econ. Entomol. 59: 1123-25.

F letcher, R. K. 1929. The uneven d istribu tion of Heliothis obsolete on cotton in T exas. J . Econ. Entomol. 22: 758-60.

F letcher, R. K. 1941. The relation of m oisture content of the cotton plant to oviposition by Heliothis arm igera and to surv ival of young larvae. J . Econ. Entomol. 34: 856-58.

54

F letcher, R. K . , and F. L. Thomas. 1943. N atural control of eggs and f irs t in s ta r larvae of Heliothis arm igera. J . Econ. Entomol. 36: 557-60.

Folsom, J . W. 1936. Notes on little known cotton in sec ts . J . Econ. Entomol. 29: 282-85.

Forbes, W. T . 1954. Lepidoptera of New York and neighboring s ta te s .F t. 3. Cornell U niversity A gr. Exp. S ta . Mem. 329: 1-433.

Fye, R. E. 1972. Cotton p est and p reda to r reservo irs in Avra Valley. P rog. A gr. in Arizona 24: 15-16.

Fye, R. E. 1975. Plant host sequence of major cotton insects in sou thern Arizona. USDA A gr. Res. Serv . W-24, 9 p .

Fye, R. E . , and R. L. C arranza. 1973. Cotton p e s ts : overw intering of th ree lepidopterous species in Arizona. J . Econ. Entomol. 66: 657-59.

Gaines, J . C. 1932. Migration and population stud ies of the cotton boll- worm moth (Heliothis obsoleta) . J . Econ. Entomol. 25: 769-72.

Garza-Blanc, L. E . , and J . M. Mathieu. 1972. DinSmica de poblalionespara Helicoverpa (=Heliothls) zea Enapodaca, N. L. Folia Entomol. Mexico, 23-24 : 33- 34. Cited in J . D. Lopez, The role of host and host phenology in the population dynamics of the bollworm, Helio­th is zea in the Brazos Valley of T exas. P h .D . d isse rta tion ,Texas A & M U niversity , College S tation, Texas

Gillham, F. E. 1963. A study in the response of the bollworm, Heliothis zea , to d ifferen t genotypes of upland cotton. P roc. 15th Ann. Cotton Improvement Conf. , D allas, T ex as , 153 p .

Graham, H. M ., N, S. H ernandez, and J . R. Llanes. 1972. The role of host p lan ts in the dynamics of populations of Heliothis sp p . Environ. Entomol. 1: 424-31.

Graham, H. M ., and O. T . R obertson. 1970. Host p lants of Heliothis v irescens and H. zea (Lepidoptera: Noctuidae) in the Lower Rio Grande Valley, Texas. Ann. Entomol. Soc. Amer. 63: 1261-65.

G rayson, J . M. 1944. Two im portant parasites of the tobacco bud worm.J . Econ. Entomol. 37: 712-13.

Greene, G. L . , and R. T hurston . 1974. Oviposition p reference ofHeliothis v irescens for Nicotiana species. J . Econ. Entomol. 64: 641-43. '

Hambleton, E. J . 1944. Heliothis v irescens as a pest of cotton, with notes on host p lan ts in P eru . J . Econ. Entomol. 37: 660-66.

55

H arding, J . A. 1976. Heliothis s p p . : seasonal occurrence, hosts , and host importance in the Lower Rio Grande Valley. Environ.Entomol. 5: 66-68.

Hardwick, D. F. 1965. The corn earworm complex. Mem. Entomol. Soc. Canada 40, 247 p .

H artstack , A. W ., J . A. Witz, and D. R. Buck. 1979. Moth trap s for the tobacco budworm. J . Econ. Entomol. 72: 519-22.

H enry , P . , and P . L. A dkisson. 1965. Seasonal abundance of bollworms and tobacco budworms on a typical cotton plantation. Texas A gr. Exp. S ta ., M.P. 767: 1-6.

Hillhouse, T . L . , and H. N. P iire. 1976. Oviposition by Heliothis on soybeans and cotton. J . Econ. Entomol. 69: 144-43)1

H uber, R. T . n .d . Unpublished research . Entomologist, The U niver­sity of Arizona, Tucson [ 1980].

H ughes, P. S. 1975. The biology of A rchytas marmoratus (Tow nsend). Ann. Entomol. Soc. America 68: 759-67.

Hughes, P. S . , and R. L. Rabb. 1976. A su rvey of tachinid parasites of Heliothis zea and H. v irescens in North Carolina. J . Georgia Entomol. Soc. 11: 25"9"-6^

Irabagon, T . A. 1973. Some bionomic fea tu res of Campoletis sonorensis (Cameron) affecting Heliothis spp . on tobacco. P h .D . thes is . North Carolina S tate U niversity , 93 p . Cited in R. E. S tinner,R. I. Rabb, and J . R . B radley, J r . 1977. Natural factors oper­ating in the population dynamics of Heliothis zea in North Carolina. P roc. 15th In te r . Cong. Entom ol., W ashington, D .C ., 1976, 622-42.

Ise ly , D. 1935. Relation of hosts to abundance of cotton bollworm. A rkansas A gr. Exp. S ta. Bull. 320, 35 p .

Jermy T . , F . E. Hanson, and V. G. D ethier. 1968. Induction ofspecific food preference in lepidopterous larvae . Entomol. Exp. Appl. 11: 211-30.

Johnson, M. W ., R. E. S tinner, and R. L. Rabb. 1975. Ovipositional response of Heliothis zea to i ts major hosts in North Carolina. Environ. Entomol. 4: 294-97.

K earney, T . H . , and R. H. People. 1950. Arizona Flora. U niversity of California P re ss , B erkeley, 1085 p .

Knipling, E. G. 1966. Some basic principles in in sect population sup ­pression . Bull. Entomol. Soc. America. 12: 7-15.

56

Knipling, E. G. 1971. Use of population models to appraise the role of larval parasites in suppressing Hellothis populations. USD A A gr. Tech. Bull. 1434, 36 p .

L acroix ,.D . S. 1936. Insect pests of growing tobacco in Connecticut. Connecticut A gr. Exp. S ta . Bull. 379: 1-130.

Lange, W. H ., and A. E. Michelbacher. 1937. Two closely relatedspecies of Heliothis found in tomato fields of cen tra l California. Bull. California D ept. A gr. 26: 320-25.

L aste r, M. L . , and R. E. F u rr . 1971. Relationship of regrow th cotton to overw intering populations of the bollworm complex. J . Econ. Entomol. 64: 974-75.

# L aste r, M. L . , D. F. Martin, and S. D. P air. 1976. Burcucum ber: anew host for the tobacco budworm. J . Econ. Entomol. 69: 193-94.

Lewis, W. J . , and J . R. Brazzel. 1968. A th ree -y ea r study of parasites of the bollworm and tobacco budworm in M ississippi. J . Econ. Entomol. 61: 673-75.

Lincoln, C. 1972. Seasonal abundance, p . 2-7. In D istribu tion , abun­dance, and control of Heliothis species in cotton and o ther host p lan ts. So. Coop. S er. Bull. 169. A rkansas A gr. Exp. S ta.

Lincoln, C . , J . R. Phillips, W. H. Whitcomb, G. C. Dowell, W. P . Boyer,K. O. Bell, J r . , G. L. Dean, E. J . Matthews, J . B . G raves,L. D. Newsom, D. F . Clover, J . R. B radley, J r . , and J . L. B agent. 1967. The bollworm—tobacco budworm problem in A rkan­sas and louisiana. Louisiana Tech. Bull. 720: 1-66.

L ingren, P . D . , R. L. Ridgway, and S. L . Jones. 1968. Consumption by several common arthropod p reda to rs of eggs and larvae of two Heliothis species th a t a ttack cotton. Ann. Entomol. Soc. America 61: 613-18.

Lopez, J . D. 1976. The role of host and host phenology in the popula­tion dynamics of the bollworm, Heliothis zea in the Brazos Valley of Texas. P h .D . d isserta tion , Texas A & M U niversity , College Station, 199 p .

L ukefahr, M. J . 1970. • The tobacco budworm situation in the Lower Rio Grande Valley and no rthern Mexico, p . 140-49. In Proc. 2nd Ann. Texas Conf. In sec ts , P lant disease. Weed and B rush Con­tro l. Texas A & M U niversity , College Station.

L ukefahr, M. J . , J . E. Houghtaling, and H. M. Graham. 1974. S uppres­sion of Heliothis populations with glabrous cotton s tra in s . J .Econ. Entomol. 67: 486-88.

57

L ukefahr, M. J . , L. W. Noble, and J . E. Houghtaling. 1966. Growth and infestation of bollworms and o ther in sects on glanded and glandless s tra in s of cotton. J . Econ. Entomol. 59: 817-20.

Maxwell, F. G ., and P . R. Jenn ings. 1980. Breeding P lants R esistan t to In sects . John Wiley & Sons, New York, 681 p.

McGinnies, W. G. 1980. Native d esert plant flowering seasons, Tucson v icin ity . Office of Arid Lands S tudies. U niversity of Arizona, Tucson.

Muesebeck, C . F . , and K. V. Krombein. 1951. Hymenoptera of America north of Mexico. Synoptic Catalog. USDA A gr. Mon. 2, 1420 p.

Neunzig, H. H. 1963. Wild host plants of the corn earworm and thetobacco budworm in easte rn North Carolina. J . Econ. Entomol.56: 135-39.

Neunzig, H. H. 1969. The biology of the tobacco budworm and the corn earworm in North Carolina. North Carolina A gr. Exp. S ta . Bull. 196: 1-96.

Nutty combe, J . W. 1930. Oviposition of the corn earworm in relation to nectar flow of some flowerin p lan ts . J . Econ. Entomol. 23:725-29.

Oatman, E. R . , and G. R . P la tner. 1972. An ecological s tudy of lepi-dopterous pests affecting le ttuce in southern California. Environ. Entomol. 1: 202-4.

Palmiter, R. D. 1966. Absence of olfactory conditioning in an oligo-phagous in sect, the corn earworm, Heliothis zea. Anim. Behav. 14: 236-38.

P ark er, K. F. 1972. An Illu stra ted Guide to Arizona Weeds. U niversity of Arizona P ress , Tucson, 338 p.

Parsons, F . W. 1940. Investigations on the cotton bollworm, Heliothis arm igera. III. Relationships between oviposition and the flower- curves of food p lan ts. Bull. Entomol. Res. 31: 147-77.

Patana, R. 1969. Rearing cotton in sects in the laboratory . USDA ARS Prod. R es. Rep. 108.

Payne, J . A ., and S. G. Polles. 1973. Pecan: A new host fo r tobacco budworms and corn earworms. J . Econ. Entomol. 67: 295-96.

Phillips, J . 1978. C u rren t research aimed a t speeding up budworm/ bollworm identification. A gr. Fieldman and C onsultant 34(3).

58

Phillips, W. J . , and G. W. B arber. 1929. A study of hibernation of the corn earworm in V irginia. Virginia A gr. Exp. Sta. Tech. Bull.40, 24 p .

P o tte r, M. F . , R. T . H uber, and T. F. Watson, N .d . Heat un it req u ire ­ments for emergence of overw intering tobacco budworm, Heliothls v irescen s, in Arizona. Environ. Entomol. In p ress [ 1981].

P o tte r, M. F . , and T . F . Watson, n .d .a Induction if diapause in thetobacco budworm in Arizona. J . Econ. Entomol. In p ress [1981].

P o tter, M. F . , and T. F . Watson, n .d .b . Termination of diapause in the tobacco budworm in Arizona. J . Econ. Entomol. In p ress [1981].

Quaintance, A. L . , and C. T . B rues. 1905. The cotton bollworm. USDA B ur. Entomol. Bull. 50: 112 p.

Ridgway, R. L . , and P . D. L ingren . 1972. Predaceous and parasitic arth ropods as regu la to rs of Heliothls populations, p . 48-57.In D istribution, abundance, and control of Heliothls species in cotton and o ther host p lan ts. So. Coop. S er. Bull. 169, A rkan­sas A gr. Exp. S ta .

Ridgway, R. L . , P. D. L ingren, C . B. Cowan, and J . W. Davis. 1967. Populations of arth ropod p red a to rs and Heliothls spp . a fte r application of systemic insecticide to cotton. J . Econ. Entomol.60: 1012-16.

R ivers, G. W ., M. V. Meisch, and P . J . Hamman. 1965. Sesame: A new host fo r tobacco budworm and bollworm. J . Econ. Entomol. 58: 1003-4.

Roach, S. H. 1975. Heliothls s p p .: Larvae and associated parasites and diseases on wild host plants in the Pee Dee area of South Carolina. E nviron . Entomol. 4: 725-28.

S luss, T . P . , and H. M. Graham. 1979. Alozyme variation in natural populations of Heliothls v irescens. Ann. Entomol. Soc. America 72: 317-32..

Snow, J . W., and J . R. Brazzel. 1965. Seasonal host activ ity of the bollworm and tobacco budworm during 1963 in no rtheast Missis­sippi. M ississippi A gr. Exp. S ta. Bull. 712: 1-24.

Snow,. J . W. , W. W. Cantelo, A. H. Baum hover, J . L . Goodenough,H. M. Graham, and J . R . Raulston. 1974. The tobacco budworm on St. Croix, U .S . Virgin Islands: Host p lan ts , population s u r ­vey and estim ates. Florida Entomol. 57: 297-301.

59

Snow, J . W ., J . J . Hamm, and J . W. Brazzel. 1966. Geranium carolini- anum as an early host fo r Heliothis ze and H_. v irescens (Lepl- doptera: Noctuldae) in the sou theastern United S ta tes, with notes on associated p a rasites . Ann. Entomol. Soc. America 59: 506-9.

S tadelbacher, E. A. 1979. Geranium dissectum : An unreported hostof the tobacco budworm and bollworm and its role in th e ir season­al and long-term population dynamics in the Delta of M ississippi. Environ. Entomol. 8: 1153-56.

S tadelbacher, E. A. 1980. Oviposition preference of the bollworm for species of early-season host p lants in the Delta of M ississippi. Environ. Entomo. 9: 542-45.

S tadelbacher, E. A ., M. L. L as te r, and T . R . Pfrimmer. 1972. Seasonal occurrence of populations of bollworm and tobacco budworm moths in the Delta of M ississippi. Environ. Entomol. 1: 318-23.

Stadelbacher, E. L . , and D. F. M artin. 1980. Fall d iapause, w inter mortality and spring emergence of the tobacco budworm in the Delta of M ississippi. Environ. Entomol. 9:553-56.

S tadelbacher, E. A ., and A. L. Scales. 1973. Technique for determ ining oviposition preference of the bollworm and tobacco budworm for varieties and experim ental stocks of cotton. J . Econ. Entomol.66: 418-21.

S tinner, R. E . , R. L. Rabb, and J . R. B radley, J r . 1977. Natural fac­to rs operating in the population dynamics of Heliothis zea in North Carolina, p . 622-42. In Proc. XV In te rn a l. Cong. Entom ol., W ashington, D .C ., 197&.

Stone, A ., C. W. Sabrosky, W. W. Worth, R. H. Foote, and J . R.Coulson, 1965. A catalog of D iptera of America north of Mexico. USDA A.H. 276, 1696 p.

S toner, A. 1972. Insects associated with Sphaeralcea spp . in sou thern Arizona. USDA A gr. Res. S erv . ARS 33-133, 11 p .

Sundman, J . A ., and P . L. Hanna. 1963. Relative seasonal abundance of two species of Heliothis in cotton in an a rea of Brazos County, T exas. J . Econ. Entomol. 56: 235-36.

Taylor, B . B ., and S. H athorn, J r . 1981. S tub cotton in Arizona: A th ree -y ea r program summary, p . 21-23. In Cotton, A College of A griculture Report Series P-53.

T eetes, G. L . , N. M. Randolph, and M. L. Kinman. 1970. Notes onnoctuid larvae attacking cultivated sunflow ers. J . Econ. Entomol. 63: 1031-32.

60

T ietz , H. M. 1972. An Index to the described life h isto ries, early stages, and hosts of the M acrolepidoptera of the continental United S tates and Canada. A. C. Allyn, Allyn Museum of Ento­mology, Sarasota, Florida.

Thomas, F. L . , and E. W. Dunnam. 1931. Factors influencing infestation in cotton by Heliothis obsoleta. J . Econ. Entomol. 24: 815-21. .

T ilden, J . W. 1968. Cultivated snapdragons: A host of tobacco budworm. Pan-Pacific Entomol. 44: 258.

Tollefson, M .S. 1980. Personal communication. Extension P est Manage­ment Specialist, The U niversity of Arizona, Tucson.

Tumlinson, J . H ., D. E. H endricks, E. R. Mitchell, R. E. Doolittle, andM. M. B rennan. 1975. Isolation, identification, and syn thesis of the sex pheromone of the tobacco budworm. J . Chem. Ecol.1: 203-14.

van den Bosch, R . , and K. S. Hagen. 1966. Predaceous and parasitic arth ropods in California cotton fields. California A gr. Exp. S ta . Bull. 821, 31 p.

Watson, T . F. 1974. Tobacco budworm and bollworm control in w esterncotton. Proceedings, Western Cotton P roducers Conference, 79 p.

Wene, G. 1943. Sagaritis p rovancheri, an im portant parasite of the tobacco budworm. J . Econ. Entomol. 59: 820-23.

W erner, F. G. 1978. Keys for identification of parasitic insects in Arizona agricu ltu ral a reas . U niversity of Arizona Exp. S ta .Tech. Bull. 236, 38 p .

Whitcomb, W. H. 1967a. Bollworm p reda to rs in northeast A rkansas. A rkansas Farm R es. 16: 2.

Whitcomb, W. H. 1967b. Field stud ies on p reda to rs of the second in s ta r bollworm, Heliothis zea (Lepidoptera: N octuidae). J . Georgia Entomol. Soc. 2: 113-18.

Whitcomb, W. H ., and K. Bell. 1964. Predaceous in sec ts , sp iders, and mites of A rkansas cotton fields. A rkansas A gr. Exp. S ta . Bull. 690, 83 p .

Wilson, C . E. 1923. Insect pests of cotton in S t. Croix and means of combating them . V irgin Isles A gr. Exp. S ta . Bull. 3.

6