David Owens, Extension Entomologist, owensd@udel.edu
Small Grains
Insect pests continue to generally be low in small grains. In areas with historic populations of cereal leaf beetle, begin scouting for eggs and larvae. Threshold is 25 per 100 tillers.
Early Season Moth Trapping
Trap counts decreased a bit from last week at most locations, but there are pockets of continuing black cutworm and true armyworm activity. Decreases are likely a result of cool, wet weather earlier in the week suppressing some moth flight. Many thanks to Joanne Whalen for assisting with trapping efforts and to my technician Morgan Malone for checking traps despite a sudden vehicle repair need.
| Location | # of Nights | Total Catch | |
| TAW | BCW | ||
| Willards, MD | 7 | 20 | 17 |
| Laurel, DE | 6 | 11 | 20 |
| Seaford, DE | 6 | 17 | 6 |
| Sudlersville, MD | 7 (4/15) | 10 | 3 |
| Harrington, DE | 6 | 192 | 83 |
| Smyrna, DE | 7 | 183 | 7 |
| Middletown, DE | 7 | 45 | 21 |
Corn and Soybean
Corn and soybean are going in the ground now. In no-till fields, scout seedlings carefully for slug damage. Gray garden slug eggs have been hatching for several weeks now, and the forecast is calling for cool conditions next week with some rain early. Most of the marsh slugs I have seen the last couple of weeks have been adults. If planting through dense cover crop, make sure that the planter can cut through the residue and get the seed into the ground and close the seed slot as much as possible. Soil disturbance (including light turbotillage) should help reduce slug damage, but in favorable environments may not be enough. The same goes for row cleaners. Bait applications can be effective if followed by warm, sunny weather. The decision whether or not to bait a soybean field should be made no later than first plant emergence, while for corn, the decision can be delayed for 1-2 weeks after emergence. If a field is at high risk, consider delaying planting until temperatures are consistently warmer. Dense cover crop can provide shelter for slugs keeping them active near the germinating seed longer. Cover crops might also influence damage potential by providing slugs with alternative food. Recent research from Virginia suggests that slug feeding on soybean was lessened when hairy vetch and daikon radish were present, while feeding on corn was lessened in the presence of crimson clover and vetch.
Seedcorn maggot in Georgetown are late instar to early pupae. We may start seeing the next flight at the end of next week.