Black-kneed capsid

The black-kneed capsid (Blepharidopterus angulatus) is a true bug belonging to the family Miridae within the order Hemiptera. While often recognized as a predator of mites and aphids, it is also classified as a plant pest because it feeds on the tissues of various fruit trees, causing notable economic damage to crops.

This insect primarily attacks pome and stone fruits, with apple, pear, and plum trees being the most susceptible. It is a polyphagous species, frequently observed on broad-leaved trees like alder, lime, and birch, which serve as alternative hosts and reservoirs for the population to migrate into nearby orchards.

The life cycle involves overwintering as eggs inserted into the bark of twigs. As spring approaches and temperatures rise, nymphs hatch and begin feeding on succulent leaves and developing flower buds. The insect undergoes five nymphal stages before maturing into an adult, usually completing one generation per year in temperate climates.

The damage caused by Blepharidopterus angulatus is distinctive. When feeding, the bugs inject saliva that contains enzymes, leading to the formation of necrotic spots on foliage. This results in yellowing, leaf distortion, and premature abscission. Furthermore, direct feeding on fruitlets causes pitting, corky skin patches, and severe fruit deformation.

Effective management strategies combine cultural and chemical control measures. Pruning and removing infested branches can significantly reduce the egg population overwintering in the bark. During the peak of nymph activity, targeted applications of approved insecticides can keep populations below economic injury levels. Monitoring with sticky traps is highly recommended to determine the optimal timing for intervention.