Pest description and damage The mature cane maggot is about 0.3 inch in length and is the larva of a small (less than 0.2 inch) gray fly that feeds on the cambial tissues of host plants. The larvae are white and legless and feed while tunneling downward in new canes. Canes are usually 1 to 3 feet long when attacked. Young shoots wilt suddenly, and a purple discoloration appears where the maggot girdles the cane. This causes a distinct drooping, a condition often referred to as "limber neck." Canes also may show a characteristic swelling where feeding is occurring. This usually is not a serious pest. It is more often a pest of blackcaps and other cane fruits.
Biology and life history The insect overwinters as a pupa in the soil. The adult flies emerge in April. The female deposits eggs near the tops of the young canes. After hatching, the young maggots burrow into the pith of young shoots and tunnel downward. Later feeding involves girdling the cane just under the bark.
Pest monitoring Remove and burn wilted canes as soon as they are seen. Cut canes off near the base. Little loss is caused by this insect even when 60 to 70% of new canes are infested.
Cut off infested canes several inches below the wilted portion.
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