David Owens, Extension Entomologist, owensd@udel.edu
San Jose Scale Alert
Between May 27 and May 30, we will reach 400–450-degree days for San Jose scale crawler emergence to begin. University of California IPM program recommends waiting until 600 degree days (base 51) after male capture (April 13-20) before making an application. (https://ipm.ucanr.edu/agriculture/prune/san-jose-scale/). Recommended insecticides include Esteem and Senstar (scale specific), neonicotinoids (may be effective on plum curculio), organophosphates, and spirotetramat.
Plum Curculio continue to be active, and this is generally the time a second cover spray for coddling moth is recommended. Neonicotinoids and organophosphates can provide curative control, killing small larvae in fruit.