Eggplant Leaf Roller
Only the larvae cause damage to the leaves. Initial symptoms appear as lengthwise rolled leaves where the larvae are located. From there, they chew on the internal green tissue of the leaves. The damage appears on the top parts of the plant most. Rolled leaves can become brown, wilt and dry. When the damage is heavier, the browning spreads to entire plant parts and is followed by defoliation. This can lead to significant yield loss if the population of insects is not controlled. However, the pest is rarely a major threat to plant development and yield.
The adults are medium sized, light brown to olive green moths with a large three-sided darker patch on the outer area of the forewing. Hindwings are translucent white. The female moths lay eggs in groups of about 8-22 on the upper side of the leaves, more commonly on the younger ones. After about 3-5 days the larvae hatch. They are purple-brown and stout with yellow or cream hollow bumps and long hairs on the back. The larval growth period is about 4 weeks. Then they pupate inside the rolled leaf. After an additional period of about 7-10 days the new generation of adult moths hatch. There may be 3-4 generations per year, depending on climate conditions.
Biological control by parasitic wasp species such as Cotesia spp. can be used to reduce the infestation. Also predatory insects such as mantis or beneficial ladybird beetle species may help to control the pest. Nematodes such as Steinernema spp. may help controlling the pest, too.
Always consider an integrated approach first. If insecticides are needed, spray products containing carbaryl or malathion to reduce populations of the eggplant leaf roller.