Prune > Year-Round IPM Program > Bloom > Monitor for Leafrollers, Other Caterpillars

Prune

Monitor for Leafrollers and Other Caterpillars

Bloomtime applications of Bacillus thuringiensis for peach twig borer help to keep leafroller and other caterpillar populations under control. Leafroller damage is not a problem for prunes grown for the dried market, but needs to be monitored on fresh market prunes so that prompt action can be taken if damaging populations develop.

Monitor for the presence of caterpillars from the beginning of bloom (green fruitworm) through petal fall (leafrollers), looking for any species that may cause fruit damage. Carefully check young leaves and shoots for the presence of peach twig borer and leafroller larvae and leaf damage. Use a beating tray to catch green fruitworm larvae that drop from the tree as you shake blossom clusters.

Use the photos below to identify caterpillars that are present in the orchard at this time of year. Names link to more information on identification and management.

Click on photos to enlarge

Peach twig borer Identification tip: Darker body segments give older larvae a distinctive ringed appearance.	Fruittree leafroller Identification tip: Green larva with dark head, hangs from silken thread when disturbed.
Obliquebanded leafroller Identification tip: Yellowish-green larva with brown head, hangs by thread when disturbed, difficult to distinguish from fruittree leafroller.	Green fruitworms Identification tip: Green larva with pale-green head and several white lines on sides and back.
Western tussock moth Identification tip: Colorful prominent tufts of hair.	Cankerworms Identification tip: Green larva with green head; only two prolegs—moves in inchworm fashion.