Corn Earworm; photo by David Handley
Hurricane Isaac appears to have only caused a mild bump in pest numbers in Maine corn over the past week, and it is likely that cooler temperatures will slow pest activity in the coming days. Any silking corn remaining requires protection from corn earworm statewide, but fall armyworm and European corn borer are only at problem levels in a few sites. Read more>>
Fall Armyworm and European Corn Borer also remain scarce.
Corn Earworm Moth, photo by David Handley
Although insect counts have been very low in Maine for this time of year, the passing of a tropical storm like Issac can bring with it a significant population of corn pests, especially corn earworm and fall armyworm, so we should anticipate higher pressure by the end of the week for any fresh silking corn remaining in the field. Read more>>
Fall Armyworm on Corn Silk; photo by David Handley
Recent relatively cool nights in Maine indicate a shift in the weather pattern and have resulted in a dramatic drop in corn earworm captures this week. However, populations are still high enough to keep all silking fields on a regular spray schedule. As we approach Labor Day and the season starts to wind down, we have very little pressure from either fall armyworm or European corn borer. Hot weather predicted for the remainder of the week will push remaining corn maturity along rapidly. Remnants of hurricane Isaac may visit Maine next week and could bring with it a new flush of earworm and armyworm. Read more>>
Corn Earworm Feeding on Corn; photo by David Handley
With continued southerly weather and thunderstorms passing through Maine, insect pressure has remained high, mostly due to corn earworm. At this point, every location is on at least a 4-day spray interval, with some locations on 3-day intervals. For many growers, the youngest corn has reached the silking stage as the corn season begins to come to a close. Warm weather will continue to help corn mature rapidly and insect pressure will likely remain relatively high. Read more>>
Corn Earworm Larvae; photo by David Handley
Warm weather in Maine has pushed corn maturity along rapidly and supplies are picking up. A steady flow of weather from the south, including some heavy showers in some areas, is keeping corn earworm pressure very high in most fields this week. Several locations are now on a recommended 3-day spray interval, which we don’t typically see until early fall when tropical storms start moving through Maine.
European Corn Borer Larvae on Pre-tassel Stage Corn; photo by David Handley
Corn harvest is in full swing across most of Maine after the warm weekend weather. Insect pressure has increased, especially from corn earworm with many locations being placed on 4-day spray intervals. European Corn Borer pressure has remained low with the exception of a few northern locations, and fall armyworm appears to be slightly on the rise, but hasn’t exceeded thresholds anywhere. With the prospect of southerly thunderstorms throughout most of the next week, insect pressure is not expected to decrease.
CORN EARWORM PRESSURE INCREASES IN SOUTHERN MAINE
European Corn Borer and Fall Armyworm Threat Remains Small
Corn Earworm Moth; photo by David Handley
Corn harvest is still spotty as growers work through the erratic early corn and hope for better uniformity and quality with the main season crop. Many fields received just enough rain to get a break from irrigation this week. A little bit of weather coming up from the southeast coast appears to have bumped up local corn earworm populations, so silking corn is likely to need protection, especially in the southern and coastal areas of the state.
European Corn Borer larvae on pre-tassel stage corn; photo by David Handley
Moth counts continue to be fairly low this week, although with the advent of silking corn in southern Maine we should pay close attention to these counts. Moths may lay their eggs on the flag leaves of silking corn resulting in larvae entering the ears through the silk channels without leaving any visible signs of feeding on the foliage. Therefore, if 5 or more European corn borer moths are caught in a trap over a week in the presence of silking corn, a spray to protect the silks is recommended. We continue to find feeding injury from small larvae in whorl and pre-tassel stage corn, but only fields scouted in Biddeford and Warren were over the recommended spray threshold. Corn in the whorl stage should be sprayed if fresh feeding injury is found on 30% or more of the plants in a field. At the pre-tassel stage, the control threshold is lowered to 15%. Read more>>
European Corn Borer Trap; photo by David Handley
The recent hot spell has pushed corn growth along rapidly, and brought us our first corn earworm of the season. Many early fields are approaching the pre-tassel stage, and should be getting a side dressing of nitrogen, if needed. Some corn started under plastic in southern Maine is now tasseling and showing some silk. Soil moisture levels remain pretty good in most locations due to the over abundance of rain earlier.
European Corn Borer and Common Armyworm are feeding in Southern Maine. Read more>>
European Corn Borer Scouting; photo by David Handley
The 2012 University of Maine Cooperative Extension Integrated Pest Management (IPM) program for sweet corn is underway. More than twenty volunteer farms will be serving as pest monitoring and demonstration sites this year, with fields in North Berwick, Wells, Hollis, Cape Elizabeth, New Gloucester, Poland Spring, Auburn, Lewiston, Sabattus, Dresden, Jefferson, Nobleboro, Warren, Monmouth, Wayne, Oxford, Farmington, Levant, Stillwater, Garland, and East Corinth. Pheromone traps are being set up at these farms to monitor the adult (moth) stages of European corn borer, corn earworm, and fall armyworm, and we will be scouting these fields for feeding injury by insect larvae. We will share the information we collect at these sites and management recommendations every week during the season through our Sweet Corn IPM Newsletter. Read more>>
