Bryan Jensen, Department of Entomology and IPM Program
The adult flight of seedcorn maggot has recently peaked in southern Wisconsin while the central and northern areas are now peaking. Keep this time period marked in the back of your mind in case you run across corn and/or soybean field with poor plant stands at a later date. There are many, many reasons for reduced stands. Please remember that seedcorn maggots is one. If it is seedcorn maggot damage, you should notice a range of above ground symptoms that include small holes in either the first and/or second leaf as well as missing plants. In soybeans, you may also find “snakeheads” (plants with a hooked hypocotyl and no cotyledons) for a short period of time. In corn you still be able to find the seed coat for a number of weeks after planting indicating the seed was planted and that something was feeding on it. Feeding injury is usually uniform across fields and is may be more severe under the 2018 cool/wet planting conditions. Corn and soybeans which are planted into a green manure or in fields with heavy applications of livestock manure may have higher than expected levels of damage.