Green shield bug

The green shield bug (Palomena prasina) is a member of the Hemiptera order and the Pentatomidae family. Widely distributed across Europe and Asia, this insect is frequently encountered in domestic gardens, orchards, and agricultural fields, where it acts as a sap-sucking pest of various botanical species.

The host range of this insect is remarkably broad. It affects numerous fruit trees, such as apples and pears, soft fruits including raspberries, and various legumes and vegetables like tomatoes and beans. Its ability to switch between wild and cultivated plants allows it to maintain high population densities throughout the growing season.

Regarding its biology, the species typically completes one generation per year. Adults hibernate in sheltered locations, such as leaf litter or crevices in tree bark. Following emergence in spring, they feed and mate, with females depositing clusters of eggs on the underside of foliage. The nymphs go through five instars before reaching adulthood, with each stage requiring plant sap for development.

The damage caused by Palomena prasina is characterized by the piercing of plant tissues and the injection of digestive enzymes. On fruit, this results in the formation of pitted, necrotic spots, often referred to as "cat-facing" or stippling. Consequently, affected fruit loses its commercial value, tastes bitter, and is prone to premature decay or shedding.

Integrated Pest Management (IPM) is essential for effective control. Cultural practices, such as removing weeds that serve as alternative hosts and managing hedge boundaries, are highly effective. When infestation levels exceed economic thresholds, the application of selective insecticides or organic alternatives during the nymph stage is recommended to minimize damage and prevent significant yield losses.