By Dr. Erin Hodgson
This summer, I am starting a couple of new research projects looking at cover crop pest activity that might be relevant to corn production. Shout out to Alison Robertson and Mark Licht for including me on these massive research projects! The usual cover crop pest suspects are migratory moths, like black cutworm and true armyworm, that make their way to Iowa every spring. There isn’t much green around in March and April, so female moths like to lay eggs on early-season weeds and cereal rye. Flights up north are based on weather and other factors in the southern US, but generally results in erratic, aggregated infestations.
Our data collections at several ISU Research Farms started last week. We are looking for any pests feeding on cereal rye that could spill over to seedling corn. Our focus was searching for caterpillars, but really we were looking for anything. So far, we haven’t found any caterpillars but found aphids feeding on rye at all locations! This made me particularly happy, as aphids are my main research focus. However, I realize most people wouldn’t be happy to see aphids in field crops.
I think I found two species so far: English grain aphid and bird cherry-oat aphid. They are small grain aphids that can feed on rye and corn. My experience with English grain aphid is they can be found early in the season but do not persist later in the summer. Perhaps natural enemies, insecticidal seed treatments or other factors limit the success of English grain aphid in our area. Bird cherry-oat aphid can persist after pollination and interfere with plant quality.
Winged aphid on rye.
Wingless aphid on rye.