Pink Bollworm Management and Integrated Pest Control
Pink Bollworm: Pectinophora gossypiella
Systematic Position
- Class: Insecta
- Order: Lepidoptera
- Family: Gelechiidae
Habits and Behavior
The pink bollworm is a nocturnal insect. At night, the insect is attracted toward light. Caterpillars feed on and destroy seeds, which obstructs lint formation. The adults mate immediately after emergence.
Crop Damage and Economic Impact
The caterpillar causes the primary damage by boring into shoots, bolls, and flowers. It damages young seeds and reduces lint production, while also harming already formed cotton. Attacked bolls often fall off prematurely. Consequently, the damaged crop yields less seed, less oil, and inferior fiber. The pink bollworm may cause a 10–25% loss in cotton yield.
Effective Control Measures
The following measures are suggested for the control of pink bollworm:
- Resistant varieties should be grown.
- The ratoon method should be avoided.
- Hibernating larvae should be killed through proper ploughing of the field.
- Fallen leaves and buds should be collected and burnt.
- Alternate hosts in the vicinity should be removed.
- Infested crops should be sprayed with 2.5 L endosulfan, 250–300 mL phosphamidon, or 1.61 L endrin.
Life Cycle Stages
The life cycle of the pink bollworm (Pectinophora gossypiella) is completed in 22–27 days. In summer, the life cycle is completed in a short span (short life cycle), whereas in winter, it takes longer (long life cycle). Adults breed from May to November. The life cycle involves the following stages:
- Eggs: Eggs are laid by the female singly or in groups of 2–10. They are placed on young green cotton bolls, flower buds, new shoots, leaves, and leaf axils. Eggs are white, flat, and oval, measuring about 0.35 mm in length and 0.26 mm in width. A single female lays approximately 300 eggs, which gradually turn brown.
- Caterpillar: Caterpillars emerge in about 7 days. They are 1 mm long, white, cylindrical, and worm-like. They attack the crop by boring into bolls and seeds, often joining two seeds to create a resting place. The larval stage lasts for two weeks and is passed almost entirely inside the seeds. Larvae grow to 8–10 mm, developing a pink body, brown head, and two grey stripes on the sides.
Integrated Pest Management (IPM) Strategies
Integrated Pest Management (IPM) is the management of various pests by applying several methods to control them effectively. IPM can be programmed using the following methods:
- Cultural Methods: These aim to kill pests, prevent damage, or control multiplication. Techniques include crop rotation, clean cultivation, tilling of soil, use of resistant varieties, regulating irrigation, mixed cropping, pruning, and thinning.
- Mechanical Control: This involves devices that kill insects or prevent damage without chemicals, such as hand picking, jarring, using hand and bag nets, sieving, winnowing, mechanical exclusion, and traps.
- Physical Control: Environmental factors like temperature and moisture regulation help control pests. Both extreme high and low temperatures serve as anti-insect measures. Adjusting moisture content creates unfavorable conditions for pests.
- Chemical Control: Chemicals can control pest populations quickly. Five types are used: insecticides, repellents, antifeedants, hormone mimics, attractants, chitin synthesis inhibitors, and sclerotization disruptors.
- Biological Control (Natural Control): This utilizes natural enemies such as insectivorous birds, amphibians, reptiles, centipedes, and spiders, as well as disease-causing agents like bacteria, fungi, and protozoa.
- Hormones, Pheromones, and Antifeedants: Juvenile and moulting hormones, as well as sex pheromones (attractants or lures), are used for behavioral control. Antifeedants inhibit feeding.
- Legal Control: To prevent pests from traveling between countries via imported products, items must be thoroughly examined at ports and certified pest-free.