Cotton Bollworm on Sugarcane
feeding damage occurs primarily on growing points and flowering structures but may also occur on foliage. The feeding habits of the larvae include penetration and burrowing into buds, flowers and fruits depending on the host plant. The larvae are often hidden within plant organs. The bore holes in the plant tissue can lead to additional damage caused by fungal or bacterial infections.
The adults do not damage the crops.The moths are light brown with dark marks and can grow up to 35mm long. Adults can usually be detected on flowers or light sources. After oviposition next to flower structures the eggs hatch within 3-4 days. Eggs of the Bollworm are white to brown and 0.5 mm in diameter. The small larvae are white in color with little black spots and dark heads. As the disease progresses, lines and bands develop on the bodies of the larvae. H. armigera has 5-7 larval instars. Larvae drop off the host plant and pupate in the soil. Under tropic conditions a generation is complete within 30 days.
Apply bioinsecticides containing parasitic bacteria species such as Bacillus thuringiensis or Spninosad to control acute infestation. Use parasitic insect species from the Ichneumonidae, Braconidae, Scelionidae, Trichogrammatidae and Tachinidae family as biological control method in addition. Also try predatory insects from the following orders: Coleoptera, Hymenoptera, Hemiptera and Neuroptera.
Always consider an integrated approach with preventive measures together with biological treatments if available. If insecticides are needed, spray products containing chlorpyrifos, flubendiamide or acephate. Chemical treatment may be inviable in low value crops.