Lesser appleworm

Lesser appleworm caterpillars tunnel into developing stone fruits like Prunus cerasifera, creating holes with reddish-brown stained edges in affected fruit during May and June. The small caterpillars are pale and grow to about 0.5 inch long. Early infestations cause fruit drop or create tunneling damage that renders fruit unmarketable. You detect damage by examining young fruit in late April.

Scout fruit clusters in late April and early May for evidence of small caterpillars or entry punctures. Remove infested fruit by hand during early detection. For heavy populations, apply spinosad or biological insecticides targeting larvae before damage progresses. Time applications to late April. Monitor for additional generations if temperatures remain cool.