Black hairstreak

Taxonomy: The Black hairstreak (Strymonidia pruni) is a butterfly species belonging to the family Lycaenidae (gossamer-winged butterflies) and the order Lepidoptera. It is recognized as a pest specifically associated with several rosaceous trees, particularly in temperate climates.

Host plants: This pest primarily affects trees within the Prunus genus. While it is commonly referred to as a plum pest, it also colonizes blackthorn (sloe), bird cherry, and occasionally commercial apricot or cherry orchards, making it a significant concern for fruit growers.

Biology and lifecycle: The species follows a univoltine lifecycle, meaning it completes only one generation per year. It overwinters in the egg stage, with eggs attached to the bark of smaller branches. Larvae emerge in the spring to feed on buds and foliage. Adults emerge in early summer, engaging in mating and oviposition on host trees.

Nature of damage: The larval stage is the most destructive phase. Young caterpillars feed on expanding buds, often causing them to fail to open. As they mature, they consume leaf tissue, often leaving only the veins behind. This severe defoliation weakens the trees, reduces fruit set, and stunts the growth of young orchards.

Control measures: Management strategies emphasize preventive measures and targeted chemical control. Pruning and removing older, infested twigs during the dormant season can significantly reduce the overwintering population. If populations exceed economic thresholds, applying selective insecticides during the spring bud-burst phase is the most effective approach to protect tree vigor and yields.