Shoot and fruit borer (Leucinodes orbonalis)
It is a major pest of eggplant. The adult is a small moth, with a wingspan of 18-24 mm, white in colour with a pink and bluish tinge, and a few brown spots on its wings. Moths lay creamy white single eggs on leaf undersides, stems, flower buds, or the base of fruits. Upon hatching the caterpillars (white in colour) bore into the top section of fruits and tender shoots. Caterpillars develop inside fruits and stems reaching a length of 15-18 mm. When fully-grown, caterpillars make a small hole in the fruit or shoot and drop to the soil and pupate among fallen debris.
When plants start bearing fruits, most caterpillars prefer to feed on the tender fruits. The damage to the shoots is not seen until they droop as a result of the caterpillar feeding inside them. Recently damaged fruits are not easy to detect. The first indication of damage to the fruit is a small hole just below the calyx where the insect has entered. Fruits are filled with frass. They change colour and taste; they drop off and are unmarketable. Caterpillars are difficult to control with pesticides. Within hours of hatching from eggs, caterpillars enter the shoots or fruits, and are not reached by contact pesticides.
- Conserve natural enemies. Predatory ants are the main natural enemies of the shoot and fruit borer. Other natural enemies include: ladybird beetles, praying mantis, earwigs, predatory bugs and spiders.
- Destroy old eggplant plants and stubble (burn or bury them) immediately after harvest. Pupae can survive in the stubble for several weeks, infesting the new crop.
- Use healthy, pest-free seedlings. Raise seedlings far away from sources of infestation (old eggplant fields, eggplant stubble)
- Grow seedlings under nylon netting to prevent moths from laying eggs on the plants.
- Remove and destroy infested shoots (readily visible as dry tip of branches). Burn, shred into tiny pieces or bury attacked shoots at least 20 cm in the soil. If this is done by all farmers in a community, especially before fruiting, pest infestation and damage can be drastically reduced. Continue cutting attacked shoots at least once a week until the final harvest.
- Destroy infested fruits found during harvest.