Efficacy of Heligen (nucleopolyhedrosis virus) for corn earworm control in sweet corn

Corn earworm, Helicoverpa zea, is the most important pest of sweet corn throughout most of the United States.  In Virginia, typically > 90% of sweet corn ears will be damaged by this pest if control measures are not taken.  Widespread resistance to pyrethroid insecticides as well as the CRY proteins found in most Bt sweet corn varieties has caused growers to seek alternative controls.  Heligen® is a nucleopolyhedrovirus (NPV)-based biological insecticide designed to selectively control corn earworm.  In Virginia in 2020, we evaluated Heligen in an on-farm large-plot spray trial on three different plantings.  In two of three plantings (the two with the highest pest pressure), both the low (1.2 oz/A) and the high (2.4 oz/A) rates of Heligen (applied on a 3-4 day interval from tassel push to harvest) significantly increased the percentage of marketable sweet corn compared with the untreated control.  This insecticide shows promise as an OMRI-certified and biorational control tool for corn earworm.