Pectinophora gossypiella(pink bollworm)

SUBMITTED BY;

SYED MOHAMMAD.

B.SC HONS ZOOLOGY III rd YEAR.

SRI VENKATESWARA COLLEGE(DU).

GENERAL DISCRIPTION*P. gossypiella is an insect known for being a pest in cotton farming. The adult is a small, thin, gray moth with fringed wings.

*The larva is a dull white, eight-legged caterpillar with conspicuous pink banding along its dorsum. The larva reaches one half inch in length. *The pink bollworm is native to Asia, but has become an invasive species in most of the world's cotton-growing regions *The Pink Bollworm life cycle includes four stages. These are the egg, larva, pupa, and adult.

*Completes four to six generations per year.

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DISTRIBUTIONPink Bollworm is of south-Asian origin, and has spread to all regions where cotton is cultivated.P. gossypiella is distributed throughout tropical America, Africa, Asia, Australia, including subtropical regions, Pakistan, Egypt, USA (Arizona) and Mexico. The distribution includes records based on specimens of P. gossypiella from the collection in the Natural History Museum (London, UK).

In india it is distributed throughout Andhra Pradesh , Assam , Bihar , Delhi ,Gujarat, Haryana , Himachal Pradesh , Indian Punjab , Jammu and Kashmir , Karnataka , Kerala , Madhya Pradesh , Maharashtra , Manipur , Odisha , Rajasthan and Tamil Nadu.

Life Cycle*The Pink Bollworm life cycle includes four stages. These are the egg, larva, pupa, and adult. *The time required from egg to egg varies because of temperature and other conditions but generally is about one month during the summer month

Seasonal cycle---------------------

EGG*Female pink bollworm moths lay eggs singly or, more commonly, in small groups. *Eggs are white when first laid but then turn orange, and later the larval head capsule is visible prior to hatching. *The eggs are small and difficult to see without some magnification. *Eggs hatch in about three to four days after they are laid. *Eggs of the first field generation in the spring are often laid on vegetative cotton plants near cotton squares & sometimes on. Squares. *Second and sub-sequent generation eggs are usually laid under the calyx of bolls.

Larva*Larvae immediately begin to bore into squares or bolls after hatching. In squares, larvae complete most of their development before blossoming occurs and often cause rosetted blooms. Final development is completed in the blossom. *In bolls, larvae feed within one to five seeds to complete development before exiting & dropping to the soil for pupation. *While moving from seed to seed, the larva causes damage by cutting through the lint with its mouthparts. *Lint is also damaged as the larva tunnels out of the boll. *Larvae are white with a brown head when they hatch. *They have four stages of growth (instars) and begin to turn pink in the fourth instar. *They generally require 12–15 days to complete develop-ment after which they go into puation.

PupaIt is in pupation that the pink bollworm makes the drastic transformation

from a larva to an adult moth. Most pupa-

tion occurs in the top layer of soil beneath

cotton plants. The pupa is brown and

approximately one-half inch long. It does

not feed or move about during the pupal

period of seven to eight days.

ADULT*Adult pink bollworms are mottled brown to gray moths and are about 1 1/2 inch long. *They emerge from pupae in an approximately 1:1 male to female ratio. *There is a time period of 2-3 days after emergence during which the female mates and prepares to lay eggs. *After this preoviposition period the female lays most of her eggs in about ten days. *Both male and female adults feed primarily on nectaries located on the bottom of cotton leaves and may live for one to two months. The female produces a sex pheromone that aids the male in locating her for mating purposes.

Main host P. gossypiella is an oligophagous pest. Gossypium (cotton) is its main host.But apart from cotton P. gossypiella also affects the following species : Abelmoschus esculentus (okra),Abutilon (Indian mallow),Abutilon indicum (country mallow),Althaea (hollyhocks),Hibiscus (rosemallows),Hibiscus cannabinus (kenaf),Hibiscus sabdariffa (Jamaica sorrel),Malvaceae,Medicago sativa (lucerne).

MAIN HOST;Cotton and other members of the family Malvaceae, especially Hibiscus spp.

In a survey of okra, deccan hemp (Hibiscus cannabinus [kenaf]) and roselle (H. sabdariffa) in Egypt in autumn 1988, P. gossypiella was found to prefer okra over cotton towards the end of the season when the cotton boll surface was hard (Khidr et al., 1990).m

ADULT CHARACTERS*The adult pink bollworm varies in size but is rarely over 3/8 inch in length. It is mottled grey in color with oval shaped wings. *The wings are strongly fringed at the edges. The forewing is pointed at the tip. When at rest, the moth’s wings are folded close to the body. *Under magnification, palpi can be seen emerging from the lower front part of the head. *In contrast to most other moths, the palpi of pink bollworm are relatively thick, curved upwards and have light and dark colored bands. *Also, the pink bollworm moths have a few stout hairs which project forward from the base of the antenna. *Pink bollworm moths will typically live 4 to 8 days. *In the genitalia, the male uncus is broad at the base, tapering to a point and the aedeagus has a hooked tip. The female ovipositor is weakly sclerotized.

damage*Soon after emergence, pink bollworm moths mate and if cotton fruiting forms are available, the females begin laying eggs on them. *Some overwintering adults will emerge before there is squaring cotton available. *This emergence is termed “suicidal” since the eggs are laid on vegetative tissue and the larvae do not survive. *Pink bollworm larvae enter cotton fruit less than one hour after they hatch from the egg. *Squares need to be 7 to 10 days old before they can support the growth and development of a pink bollworm larvae. *The larvae feed and mature in cotton fruit. The first generation in the early summer feeds in squares, primarily on the anthers. *Pink bollworm larvae burrow into cotton bolls to feed on the cotton seeds. In the process they destroy the cotton lint. This feeding damage allows other insects and fungi to enter the boll and cause additional damage. *When the larva exits the cotton boll it leaves a perfectly round and clean cut exit hole which is diagnostic of pink bollworm damage.

Prevention and ControL*In cotton production, there are many factors that can reduce crop yield and one

important cause is the attack of insect pests. Insect pests’ attacks reduce yield and quality of cotton, and oil content in the seeds. *Cotton is vulnerable to an extensive array of insect pests and among these the cotton bollworms are the most destructive fatality. Methods for prevention and control of P. gossypiella are: *Biological Control method, *Integrated Pest Management, *Chemical Control, *Cultural Control, *Pheromonal Control, *Sterile Male Release

Pheromonal Control *Female pink bollworm moths produce and release into the air a sex pheromone which is highly attractive to male pink bollworm moths. Male moths respond to the pheromone. *Scientists have successfully produced synthetic pink bollworm sex pheromone in the laboratory. When slow release systems containing pink bollworm sex pheromone are spread throughout pink bollworm infested cotton fields, the ability of males to find females and mate is greatly impaired. *Unmated females do not contribute to pink bollworm population growth. Even delays in mating slow the rate of pink bollworm population development. *Trapping with the synthetic pheromone gossyplure has been widely used and is reported to have resulted in a 60-80% reduction of the pest population in China (Gao et al., 1992). Pheromone trapping has also been used in India for an attempted eradication programme (Simwat et al., 1988).

Biological control*P. gossypiella has been a target for biological control, particularly in the USA. Parasitoids were introduced there from India, from the Indonesia-northern Australia region and from several other countries, but only Bracon kirkpatricki became established (Greathead, 1989). *Biological control agents were first obtained from India, in the belief that it was the origin of the pest. When these failed later introductions were from Indonesia-Australia as opinion shifted in favour of an origin in this region.

*Only few natural enemies of the pink bollworm are known, and none seem to have any controlling effect.

Integrated Pest Management *Combinations of biological and chemical controls have also proved successful. Tuhan et al. (1987) found that application of Trichogramma brasiliense in combination with chemical insecticides gave good control of pink bollworm in India, and Bacillus thuringiensis has been found to be effective in combination with chemical insecticides in Egypt (Hussein et al., 1990). *The Pectinophora gossypiella IPM project in California, USA, was reviewed by Walters et al. (1998). The project used the release of sterile insects, cultural controls, intensive monitoring with pheromone baited traps for adult males and boll sampling, pheromone applications for mating disruption, very limited use of pesticides and the widespread use of genetically engineered cotton. *In Pakistan, Ahmad et al. (2001) found a combination of Biological control and mating disruption techniques to be effective.

Chemical Control*Organophosphates were used in the past to control the pest, whereas pyrethroids are more common now.

*Insecticidal control is hindered by the larvae being internal feeders; moreover, resistance to insecticides develops making it often more expensive than other methods.

*The efficacy of asymethrin has been tested in India by Dhawan et al. (1992), that of chlorpyriphos in India by Dhawan et al. (1989), of synthetic pyrethroids by Dhawan et al. (1990) and Butter et al. (1990), chlorpyrifos and fenpropathrin by Mahar et al. (1987), of chloropyrifos and teflubenzuron by Green and Lyon (1989), of pyrethroids and organic insecticides with high contact toxicity (carbaryl) in China by Gao et al. (1992), of cyhalothrin and fluvalinate in India by Thangaraju et al. (1993) and of fenvalerate by Tadas et al. (1994). Application methods were assessed in Brazil by Ramalho and Jesus (1989). A strain in Arizona has been found to be resistant to permethrin (Osman et al., 1992).

Cultural Control*Late planting of crops has been used as a cultural control method where the end of diapause is triggered by day length.Larvae that emerge before the crop is ready then have no food supply (Frisbie et al., 1989). *Threshing and thoroughly burying all plant remains after cotton picking is also recommended for pink bollworm control. *Research has shown that when a cotton producing area maintains seven or more months each year free of fruiting cotton plants, pink bollworm damage generally declines to the point that it is of minor economic significance. *Adventitious cotton plants growing around commercial fields and any harvested cotton remains lying by roadsides should also be destroyed. *Other cultural methods include killing the larvae within seeds or lint bales by heating to about 60ºC. *Winter irrigation of the previous season’s cotton fields is also a very effective cultural practice to reduce overwintering pink bollworms, and rotating to small grains, an alternative summer crop, or leaving the ground fallow over the summer will greatly reduce pink bollworm populations in a given field.

Sterile Insect Technology(SIT)*Sterile Insect Technology (SIT) is another form of highly effective, non-traditional biological control that is being used to eradicate and control pink bollworm. *IN this technique Pink bollworms are mass reared in a laboratorY. *The larvae pick up a red dye which has been added to the diet mixture so that lab reared moths can be distinguished from wild moths. *Lab reared moths are sterilized with radiation and quickly shipped in internally cooled shipper/release boxes to cotton producing locations where they are released by special equipped aircraft over targeted fields. *Sterile moths compete for mating with wild males and females. No viable larvae are produced by matings of sterile males with wild female moths. *

REFRENCE1=http://cottonbugs.tamu.edu/fruit-feeding-pests/pink-bollworm/

=http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=39417

http://www.cabi.org/isc/datasheet/39417

https://cals.arizona.edu/crops/cotton/insects/pbw/NCCPBWnewsNo2.pdf

http://www.agri.huji.ac.il/mepests/pest/Pectinophora_gossypiella/

https://www.rroij.com/open-access/the-cotton-bollworms-their-survey-detection-and-management-through-pheromones-a-review.php?aid=33796