PRIMARY WESTERN PECAN INSECT PESTS
New Mexico Pecan Short CourseSeptember 8-10, 2010
Outline• Background• Aphid Complex
– Species– Biology– Management Considerations
• Pecan Nut Casebearer– Biology– Management Considerations
• Pecan Weevil– Current Status– Prevention
Two Distinct Pecan Growing Regions
Regionalization of Pecan Pest Management Practices
1. Yield 2. Profitability 3. Pest Pressure4. Primary vs. Secondary Pest5. Cultivar
Pecan Leaf vs. Leaflet Leaf/Compound Leaf Leaflet
Pecan Aphid Complex
Black Pecan Aphid Yellow Pecan Aphid Complex
Blackmargined Pecan Aphid Yellow Pecan Aphid
Pecan Aphid Biology
Overwinter in bark as eggs
IJ. Park
Spring-eggs hatch, stem-mothers arise
Populations build and decreaseover the season, winged and non-winged females produces
Fall-males produced and mate with wingless (apterous) femaleseggs produced
No alternate-host in the area
Aphid Feeding
1. Aphid manipulates stylet between cells to find sieve elements
2. Remove products produced by photosynthesis
3. May compete with other tree “sinks” for these products
• Susan Dunford, University of Cincinnati –Photo Credit
Black Pecan Aphid1. Adults dark black, nymphs dark grey
2. Wings extend past abdomen
3. Approximately 15 day lifespan
4. Produce approximately 35 offspring
5. Populations tend to be “clumped”
6. Little “honeydew” produced
7. Feed both sides of leaflet
Louis Tedders
Black Pecan Aphid Damage
1. Interveinal necrosis/defoliation
- Reductions in photosynthesis2. May reduce nut quality*
3. Possible reductions in fruiting sites (following year)*
4. Historically considered economic
5. Damage is visible
Yellow Aphid Complex
1. Yellow Pecan AphidPresent in western orchards,
low populations
2. Blackmargined Pecan Aphid Dominate species throughout the season
Jerry A. Payne, USDA Agricultural Research Service, Bugwood.org
Mike Quinn
Blackmargined Aphids
I.J. Park
Aphid Skins
Parasitized blackmargined aphid (do not mistake for black pecan aphid)
Mike Quinn
Non-Winged Female“apterous” stem mother
Winged Female“alate”
Blackmargined Aphid
1. Adult females both winged and non-winged2. Characteristic “black band” on wings3. All forms “lime green”4. Lifespan approximately 30 days5. Produce approximately 150 offspring6. Populations tend to be uniform across the orchard7. Feed primarily on underside of the leaflet
Blackmargined Aphid Damage
1. Compete with the tree for photosynthates “sinks”*
2. May reduce nut quality*3. May reduce # flowers (next year)*4. Historically considered “secondary pest”
in other pecan growing regions5. Provide a food source for sooty mold* (honeydew)6. Damage not visible7. Premature defoliation
Quick Summary
1. Aphid species2. Damage differences3. Difference in fecundity rates
Pecan Production Basics(Aphid Control Considerations)
1. Pecans alternate between “heavy” and “light” production years.
2. Number and location of flowers are determined the previous year.
3. Pecans are considered a “high value” crop.
Aphid Control Considerations
I. Economic Threshold Levels (internet)• Black pecan aphid 1-3 per leaf• Blackmargined aphid 10 per leaf
II. Yield reductions (regional) • Approximately 2%+ reduction in meat (“heavy”
production year)• Reduce number of flowers following year (“light”
production year)• Increase in “husk retention” at harvest (“heavy
production” year)
Aphid Control Considerations(Treat or No-Treat)
I. Scout (insect) - Species- Density- Location (within, proximity to neighboring orchards)- Aphid forms (winged, stem, nymphs)- Damage (black)- Honeydew production (blackmargined)- History (how many, how long)
Aphid Control Considerations (Treat or No-Treat)
II. Scout (orchard information) - Yield estimate- Overall orchard condition - Foliar requirements (zinc)- Soil moisture
III. Equipment availability IV. Dollars
- Expected market price - Application costs (chemical, labor)
V. Climate (treatment, honeydew, sooty mold)
Insecticide Selection & Application• Number of insecticide active ingredients and activity for
aphid control– Foliar trans-laminar systemics (neonicitinoids)– Foliar true systemics (Movento*)– Soil applied systemics (neonicitinoids)– Contact (organophosphate, pyrethroids)
• Restricted vs. non-restricted• Costs $5/acre to $30+/acre • Resistance issues• Adjuvants • Application (coverage, air vs. ground, speed)
Status of Conventional Insecticides Used to Control Pecan Aphids
I. Foliar•1) Pyrethroids (co-packs) •2 ) Non-specific feeding blockers (Fulfill) •3) Neonicotinoids •4) Chlorpyriphos (Lorsban 4E to Lorsban Advanced)•5) Pyriproxyfen (Knack) •6) Spirotetramat (Movento)•7) 2012 ??
II. Systemic (soil applied)Carbamates (Aldicarb removed 2010)
Neonicotinoids
OMRI Approved Insecticides for Aphids
• Sulfur• Pyrethrin• Potassium salts of fatty acids• Aromatic Oils (i.e. rosemary, peppermint)• Azadiachtin• Plant Growth Regulator
Decisions
Pecan Nut Casebearer Basics
• Most recent pest introduced into western area*• Overwinter as a diapaused larvae in the base of pecan bud• Emerge in spring • Normally three generations throughout the growing season• Larvae feed on developing pecan nuts (direct impact), or buds• Smaller the nuts, more nuts damaged by larval feeding• Populations monitored with pheromone traps and scouting
for eggs and damage• Economic threshold levels dependent on yield
Pecan Nut Casebearer Basics
PNC Life StagesSTAGE LOCATION APPROX DURATION
(days)
Egg Nutlet, Bud 5 - 10
Larvae Nutlet, Base of Bud (overwintering)
25 - 30
Pupae Nutlet, Base of Bud 10 – 15
Adult (100-150 eggs) Omnipresent 7-10
Pecan Nut Casebearer (Western Region)
PNC Infested
Pecan Growing, PNC Uninfested
Three Pecan Nut Casebearer Generations (Moth activity)
10 16 20 DAYS
Detecting PNC Adult Populations (Pheromone Traps)
10 16 20
Placement of Pheromone Traps
Wind
1. Location2. Minimum of two traps3. Record moths and #
nights since last count4. Used to time egg
scouting5. Replace pheromone
every month6. Consider access
A
PNC Economic Decisions
• Economic Threshold Levels: (Internet)– 1% egg infested clusters for 1st generation– 2% egg infested clusters for 2nd and 3rd generation
ON-YEAR 1st GENERATION-2,500 Lbs/Acre-65 Nuts/Lb-$1.80/Lb Market-40,000 clusters/Acre-At 1% infested = 400 Clusters/acre-3 damaged nuts/cluster =1200 nuts or 18 lbs or $32 Loss
OFF-YEAR 1st GENERATION-1,500 Lbs/Acre-60 Nuts/Lb-$1.80/Lb Market-26,000 clusters/Acre-At 1% infested = 260 Clusters/acre-3 damaged nuts/cluster =780 nuts or 13 lbs or $23 Loss
Western PNC may have a high egg mortality (up to 80%)Used to thin crop load?
Pecan Nut Casebearer Management A. Timing Insecticide
Application1) Field Scouting 2) Modified Degree-Day Models
(1st gen. only)a. Biofix (Texas A&M)b. Traditional (egg survey)c. Forecast Model
3) Calendar Baseda. 12 days following accumulation
of 25 moths*
Egg
Egg Hatch, Larvae and Nut Entry
Treatment Decision
Mot
h Ca
tche
s
TIME
PNC Insecticides (General Characteristics)
Broad Spectrum• Older chemistries, less
expensive, residual less than 10 days, high degree of familiarity, reduce moth population, tend to increase aphid density
Narrower Spectrum• Newer chemistries, more
expensive, primarily target larvae, conserve beneficials, longer residual (some), good OMRI approved products
Alternative PNC Management Strategy
PNC Adult Suppression Program
No Eggs
Countable MothsSpray
Countable MothsSpray
1. Not considered IPM2. Can treat every other row3. Inexpensive4. No investment in scouting
Addition of Pecan IPM PIPE Website
• Maintained by Texas A&M• Information contributions by all pecan
belt entomology researchers• Early development phase• www.pecan.ipmpipe.org • Caution: recommendations may not be
appropriate for all growing regions
Pecan Weevil
Jerry A. Payne, USDA Agricultural Research Service, Bugwood.org
H C Ellis, University of Georgia, Bugwood.org
Texas A&M
Recently Infested
1998/2002
1999/2003
2000/2003
Weevil Infested
Pecan Weevil (1st trapped/Last trapped)
2008
Pecan Weevil Prevention
• Restrict the movement of in-shell pecan and potted pecan nursery stock from pecan weevil infested areas.
• NMDA , WPGA, NMPG, WTPGA, APGA support statewide cleaning plant and buying station inspection programs.
• NMDA, NMSU, WPGA, NMPG support pecan weevil eradication programs.
Primary pest objective is to prevent the movement of pecan
weevil into, and eradicate establishing populations in New
Mexico
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