Black-necked weevil

Paracentrocorynus nigricollis, commonly known as the black-necked weevil, is a member of the Attelabidae family within the order Coleoptera. This small beetle is morphologically distinct due to its elongated rostrum and the characteristic dark pigmentation on its pronotum, which distinguishes it from related leaf-rolling species.

The host range of this pest primarily includes various broad-leaved trees and shrubs. They are particularly attracted to young, tender foliage, making nursery plants and newly established orchards the most vulnerable environments for infestation. The beetles feed on leaves, creating small perforations before proceeding to their reproductive cycle.

The biology of this species is centered around a unique egg-laying behavior. Upon mating, the female utilizes her rostrum to manipulate leaves, rolling them into tight, cigar-shaped structures. These tubes provide a protected environment for the developing larvae, shielding them from predators and environmental stressors while offering a consistent food source.

Damage caused by this insect is easily visible through the presence of withered, rolled-up leaves attached to branches. This process significantly hampers the photosynthetic capacity of the plant. In cases of high infestation, the resulting defoliation can weaken the overall health of the tree, rendering it more susceptible to secondary infections.

Effective management requires a combination of sanitation and chemical interventions. Physical removal and destruction of the rolled leaves are essential to break the life cycle and prevent the next generation of adults. In severe outbreaks, the application of targeted insecticides during the early stages of adult emergence is highly recommended to protect vulnerable foliage.