Southern green stink bug

The Southern green stink bug (Nezara viridula) is a member of the Pentatomidae family. Adults typically measure 12–15 mm in length and possess a uniform bright green, shield-shaped body, although some variations with yellowish or reddish markings can occur.

Females lay clusters of eggs on the underside of leaves. The nymphs go through five instars, progressively changing color from reddish-brown or black with light spots to a vibrant green. This transformation process is critical for pest identification in the field.

This pest is a highly polyphagous insect that attacks over 100 plant species. Major agricultural crops affected include soybeans, beans, peas, tomatoes, peppers, and various fruit trees, causing significant economic losses.

Stink bugs damage plants by piercing tissues and sucking sap with their proboscis. This feeding behavior causes shriveling, malformation of fruits and seeds, internal necrosis, and the abscission of young buds and flowers.

The life cycle of Nezara viridula is highly dependent on climate, with more generations occurring in warmer regions. Adults overwinter in leaf litter, debris, or sheltered buildings to survive lower temperatures.

Activity begins in early spring as temperatures rise. The most intense damage usually occurs during the reproductive stage of the host plant, when the bugs aggregate to feed on developing seeds or ripening fruits.

Signs of infestation include necrotic spots on leaves and stems where the insect has fed. Fruits often develop sunken, dimpled, or corky areas which reduce quality and marketability.

• Pitted or deformed seed pods.
• Cloudy spots on fruit surfaces.
• Presence of egg masses on foliage.
• Unpleasant odor upon physical disturbance of the plant.

Integrated Pest Management (IPM) is essential for controlling this bug. Cultural practices, such as maintaining weed-free field margins and removing crop residues, can significantly reduce overwintering sites.

Biological control involves utilizing parasitoids, such as the egg parasitoid Trissolcus basalis. Chemical control should be reserved as a last resort, utilizing selective insecticides that minimize impact on beneficial insects and pollinators.