VegNet Vol. 14, No. 27. August 23, 2007

Ohio State University Extension Vegetable Crops
On the WEB at:  http://vegnet.osu.edu

In This Issue

1. Corn earworm alert

Corn earworm alert! By Celeste Welty

Sweet corn growers should be aware that we have enormous populations of corn earworm moths arriving in Ohio this week, as detected in pheromone traps. Thus far our record-breaking pheromone trap is one at South Charleston in Clark County, which caught 388 earworm moths in a single night on 8/22. The catches in Columbus have been very high, with 303 moths in two nights. Even at Celeryville, where no earworm moths have been trapped in recent weeks, there was a catch of 69 earworm moths this week. A few sites reported lower catches: 4 moths at Springfield in Clark County, 6 earworm moths at Fremont in Sandusky County, and 12 earworm moths at Elmore in Ottawa County. Large catches of earworm moths in traps indicates the likelihood of large numbers of eggs being laid on sweet corn in the fresh silk stage. When moth density is this high (>90 moths per trap per week), and air temperatures are high (>80F), then ears can be protected from earworm damage by a 2-day schedule of insecticide sprays during silking. If moth density remains high but temperatures drop below 80F, then a 3-day schedule will be adequate. The latest catches from Ohio trap cooperators are posted at: http://bugs.osu.edu/welty/CEWTrapSummary2007.htm