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.