Four-banded currant midge

The four-banded currant midge (Resseliella quadrifasciata) is a specialized insect pest belonging to the Cecidomyiidae family within the order Diptera. This pest primarily targets currant bushes, causing significant damage to the plant's vascular tissue through its larval development stages.

The biology of this pest is synchronized with the growth cycle of the host plant. Larvae overwinter in the soil beneath the bushes within protective cocoons. In spring, when temperatures rise, adults emerge and oviposit in the crevices of the bark or damaged areas of the stems, initiating a new generation.

The damage is caused primarily by the larvae feeding beneath the bark layer. By consuming the cambium and phloem, they interrupt the sap flow, leading to localized necrosis. This results in the weakening and eventual drying of the affected branches, which directly impacts the fruit-bearing capacity of the crop.

Symptoms of infestation include darkening and cracking of the bark on stems, followed by premature leaf yellowing and dieback of individual branches. Given the microscopic size of the larvae, gardeners often notice the damage only after the branch has already begun to wither or die.

• Pruning and removal of all infested branches to reduce population levels.
• Mulching the soil around the base of the bushes to inhibit adult emergence.
• Protecting the bark from physical damage to reduce suitable egg-laying sites.
• Applying specific insecticides during the critical periods of adult flight if population thresholds are met.