Sweet Corn
European corn borer (ECB) moths catches have declined to nearly nothing over the past week (see map at left). Feeding percentages have increased, and should peak over the next 5-7 days. As of the weekend, feeding percentages as high as 24% in Cape May and 60% were found in whorl corn in Somerset County, but these numbers seem to be outliers. The majority of feeding is in the 2-14% range throughout much of the state.
Growers should scout whorl and pre-tassel stage plantings weekly. Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample. As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left). It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time. This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.
Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen. Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn. Control with these materials is very inconsistent.
The highest nightly trap catches of ECB for the week ending 6/12/19 are as follows:
Califon 1 | Milford 1 |
Hillsborough 1 | Pedricktown 1 |
Medford 1 | South Branch 1 |