How to Manage Pests
UC Pest Management Guidelines
Scientific name: Otiorhynchus cribricollis
(Reviewed 10/14, updated 10/14)
In this Guideline:
DESCRIPTION OF THE PEST
Adults are dark brown, compact weevils up to 0.5 inch long with longitudinal striations. They are flightless and nocturnal, hiding at the base of fruit or under dirt clods during the day and crawling up the tree at night to feed. Larvae are white, legless grubs that feed on tree roots. There is one generation per year.
Adults feed on foliage, chewing notches out of the leaf edge and giving it a ragged appearance. Under high population pressure, only the midvein of the leaf will remain. The bark on the smaller shoots may also be consumed, leaving a rough, sandpaper-like surface. Mature trees can withstand attack without significant damage. Replanted, young trees may be severely defoliated and die. No damage from larval feedinghas been documented.
To prevent infestation apply a 3- to 4-inch band of sticky material such as Tanglefoot and Stikem Special to the young tree trunks to trap crawling adults in May when the first adult feeding is observed. First, wrap the trunk tightly with plastic wrap so that the weevils can't crawl beneath the wrap. Apply the sticky material to the plastic wrap, not the tree, because it can soften bark. Reapply the sticky material when it becomes dirty or loses its effectiveness. Remove the bands before winter. No insecticidal treatments for this insect have proven effective.
UC IPM Pest Management Guidelines:
Insects and Mites
W. W. Coates, UC Cooperative Extension, San Benito County
Acknowledgment for contributions to Insects and Mites:L. C. Hendricks, UC Cooperative Extension, Merced County