From Alan Eaton, UNH Extension IPM Specialist
July 20, 2017 Sweet corn pests – This year our sweet corn trapping network is basically in Hillsborough county, with a couple of sites in Merrimack & Cheshire counties. We detected our first corn earworms (just a couple) in late June. The week of July 9, it increased to 20. By July 19, the catch had jumped to 32, out of about 14 sites. So fresh silking corn is at risk of earworm attack in much of southern New Hampshire. Fall armyworm prefers younger corn, and we found our first ones in the last few days (10 as of 19th). They create messy holes with lots of visible frass.
We don’t know how far North these moths are now, but you can view the recent catches at our IPM Trapping Data website. The data is updated on weekends.
Spotted wing drosophila (SWD) – SWD was first detected, and is increasing, earlier in the growing season than in prior years. This appears to be the case throughout New England. George, Alan and Linda are seeing potentially damaging numbers of SWD in traps present in cherry, raspberry, blueberry, and also in late varieties of strawberry. While you can look at the NH trapping data, growers intending to manage this pest should set up their own traps, in order to make effective decisions about when they need to make insecticide applications.
Directions for making an SWD trap (plus lots of other good information) are available at the UNH SWD page. However, an effective commercial trap and bait is now available from Scentry. The trap is reusable and the bait lasts 4-6weeks. Cost for both is about $15 plus shipping, it is available from Great Lakes IPM Company (http://www.greatlakesipm.com/). Other good resources for SWD information include Michigan State University, and the University of Maine.