Sorghum ear head caterpillar, Helicoverpa armigera, Family Noctuidae, Order Lepidoptera, or Gram Caterpillar, is a polyphagous pest, it feeds on a variety of plants, but its primary host is sorghum. It feeds on the heads, stems, flowers, and young leaves and can cause considerable damage if left unchecked.
If the infestation is severe, the crop can be completely lost. To effectively manage this pest, it is important to understand its life cycle, its preferred habitats, and the best methods for controlling it. This article will provide information on the sorghum stem borer pest, including its symptoms, identification techniques, and control.
Ear Head Caterpillar Management in Sorghum
Life Cycle of Sorghum Ear Head Caterpillar
The lifespan includes egg, larva, pupa, and adult. The female moth lays eggs on sorghum plants, inflorescences, or leaf undersides. They hatch into first-instar larvae after 1-2 weeks. Blackheads and short hairs cover these yellowish-green larvae. They feed on sorghum foliage and may bore into cobs, ears, and tassels, causing significant harm.
Before pupation, larvae molt three times. They will grow bigger, darker green, and have long hair. They will also eat more leaves and bore into cobs and ears. In India, the sorghum ear head caterpillar is most busy during flowering and grain-filling. Larvae make silken cocoons to become moths after pupation. Adult moths bond and lay eggs, restarting the cycle. The sorghum ear head caterpillar’s life cycle can last one month or three months in cooler regions.
Occurrence of Sorghum Ear Head Caterpillar
- Location of Sorghum Shootfly: The pest occurs in South India, USA, and Western Africa.
- Host range: The pest can cause an infestation in Cotton, sorghum, lab, soybean, pea, safflower, chilies, tomato, groundnut, tobacco, gram, okra, and maize.
Identification of Sorghum Ear Head Caterpillar in Sorghum field
- Egg: Creamy white, spherical, laid in solitary.
- Larva: The color ranges from brown to green, with deep brown-grey lines on the body with lateral white lines.
- Pupa: It persists in soil, leaf, pod, and crop debris and is brown.
- Adult: Moth is pale brownish yellow, stout. Forewings are ovoid to pale brown with a deep brown circular spot in the center. Hindwings are pale smoky white with a broad blackish outer margin.
Damage Symptoms of Sorghum Ear Head Caterpillar in Sorghum field
- The caterpillars partially consume earheads. Presence of small holes in the husks of the sorghum ears. The caterpillar causes these holes as it feeds on the seed.
- Caterpillars may also form webs around the ears and exhibit a chalky appearance.
- Presence of frass, or caterpillar droppings, on the lower side of the ear. These droppings are a sign that the caterpillar is present and actively feeding. Frass may also contain bits of husks and grain, which further indicates feeding.
Percentage of Yield Lose in Sorghum due to Sorghum Ear Head Caterpillar
Generally, In India, losses due to this pest can be as high as 25-50% in severe infestations. The losses are greater when the infestation is combined with other pests, such as stem borers