Helicoverpa armigera and H. punctigera are major pests of traditional cotton crops. They look alike and do similar damage, but it’s essential to tell them apart because H. armigera has become resistant to pesticides. These two species are usually called “fruit borers” because they bore into the cotton plant’s fruit or boll and inflict harm. Cotton crop output and quality may suffer as a result. Cotton is a plant in the genus Gossypium, which has four species: G. hirsutum, G. barbadense, G. arboreum, and G. herbaceum.
These are perennial plants grown for their fluffy fiber, which protects the seeds. G. hirsutum makes up most of the world’s production. Cotton plants have a central stem, branches, spirally arranged leaves, and triangular lobes. They produce single, red-purple, yellow, or white flowers, followed by a leathery seed capsule, or ‘boll,’ containing white cotton fibers and seeds. Cotton plants grow to about 1-1.5 meters and are usually grown annually, lasting one growing season.
Fruit Borer (Helicoverpa) management in Cotton
The life cycle of Fruit Borer (Helicoverpa)
The fruit borer (Helicoverpa) has four stages in its life cycle: egg, larva, pupa, and adult. The adult moth lays her eggs on leaves or cotton bolls. The larvae dig into the boll after hatching, eating the growing cotton fibers and causing crop damage. The larvae pupate inside the boll before developing into the adult moth. The adult moth may fly and lay eggs, resulting in a fast population increase under favorable conditions.
Favorable conditions favoring an increased population of Fruit Borer in the field
- High temperatures accelerate fruit borer life cycle expansion, increasing population.
- The fruit borer thrives in high humidity and wind.
- Long cotton growing seasons make time for fruit borer generations.
- Green cotton bolls attract the fruit borer and boost the population.
- Lack of natural predators, including birds, spiders, and parasitic wasps, can increase fruit borer populations.
- Poor field management: Late or poor pesticide treatments might let the fruit borer grow.
- Drought, insect damage, and disease can make cotton plants susceptible to fruit borer attacks.
- Understanding these favorable conditions helps create pest control techniques and reduce the fruit borer’s impact on cotton crops.
Identification of the Fruit Borer (Helicoverpa)
- Eggs – Spherical, oval in shape, and creamy white, presented singly
- Larva – Color varies from greenish to brown. It features dark brown-grey lines on the body, lateral white lines, and dark and pale bands.
- Pupa – Brown in color, found in soil, leaves, pods, and agricultural trash.
- Adult Light pale brownish yellow thick moth. The forewings are olive green to pale brown, with a dark brown circular mark in the center. The hind wings are light smoky white with a blackish outer border.
Symptoms of damage by Fruit Borer (Helicoverpa)
- Cotton Bolls with circular boreholes that are regular due to fruit borer attacks.
- Larvae were observed feeding on the boll by inserting their heads into the borehole and leaving the rest of their bodies outside.
- Granular feces pellets were found outside the borehole.
- A single larva may negatively impact 30-40 bolls.
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