Eggplant, or Brinjal, is a popular vegetable prized for its versatility and unique taste. However, various pests often threaten eggplant crops, including the notorious stink bugs. Stink bugs are a type of insect that can cause significant damage to eggplant crops, leading to decreased yields and economic losses for farmers. These bugs damage the fruits and cause other issues, such as unsightly blemishes and reduced quality.
Management of Stink Bugs in Eggplant
The Life Cycle of Stink Bugs
- Eggs are laid by female stink bugs in clusters, usually on the undersides of leaves. The number of eggs in each cluster can vary depending on the stink bug species, with some species laying up to 60 eggs per cluster.
- Once the eggs hatch, the nymph stage begins. The nymphs look very similar to the adult stink bugs but are much smaller. To grow, the nymphs must undergo a process called molting. During molting, the nymphs shed their outer covering or exoskeleton to make room for their larger body. Stink bug nymphs typically go through five molting periods, each known as an “instar.” It’s during the last instar that stink bugs develop their wings.
- After the final molting period, the stink bug enters its adult stage. Adult stink bugs can range in color from brown to green and have a distinct shield-like shape. They can reproduce, and females will continue to lay eggs throughout their lifetime.
- The entire life cycle of a stink bug can take anywhere from 4-6 weeks, depending on the species and environmental conditions.
Identification of Stink Bugs in Eggplant Field
- Egg clusters are common on the underside of leaves, with light-colored clusters of about 25 eggs, up to 60 for brown stink bugs, arranged on end. Brown marmorated eggs are elliptical, while other stink bug eggs are more barrel-shaped.
- Nymphs go through five developmental stages and are flattened like adults but rounder. Brown marmorated stink bug nymphs have short strips of red-brown and black with black and white banding on the antenna and around the abdomen, like adults, plus on legs. Brown stink bug nymphs are yellow-brown to brown, while green stink bug nymphs vary from yellow-orange to black, reddish, and greenish.
- Adult stink bugs are shield-shaped and about 5/8″ in size. Brown marmorated stink bugs are mottled brown and cream with black and white banding on the abdomen edge and the antenna. Brown stink bugs are brown, while green stink bugs are green with white specks.
Damage Symptoms of Stink Bugs in Eggplant Field
- Wilting and stunted growth: Large infestations of stink bugs can cause eggplant plants to wilt, become stunted, and misshapen.
- Misshapen or aborted fruits, seeds, and buds: Stink bugs can cause eggplant plants’ fruits, seeds, and buds to become deformed or even completely aborted.
- Yellow or white blotches on leaves: Stink bugs can cause yellow or white blotches to appear on the leaves of eggplant plants.
- Calluses, blemishes, or depressions: Stink bugs can cause calluses, blemishes, or depressions to appear on the fruits of eggplant plants.
- Black pits on nuts: Stink bugs can cause black pits to appear on the nuts of eggplant plants.