Know What Is On and In Your Corn and Soybean Seed

David Owens, Extension Entomologist, owensd@udel.edu

If you had an issue with western corn rootworm last year and plan to keep the field in corn for next season, be sure to look into varieties with corn rootworm protection. Trait packages are summarized well in the Handy Bt trait table: https://www.texasinsects.org/bt-corn-trait-table.html.

Timely planted corn will escape serious injury from Lepidopteran pests, and the primary target for most of the Bt traits, European corn borer, is not an economic threat to corn in Delaware due to the wide use and adoption of Bt corn. That does not mean it is gone, just present at very low levels. What this means is that there is an opportunity for producers to plant non-Bt corn and not risk the crop due to Lep pests. Every year, we have a couple of conventional, non-Bt corn varieties in the variety trial, and some of them have performed quite well (and in truth, some have not). Variety trial results can be found https://www.udel.edu/academics/colleges/canr/cooperative-extension/sustainable-production/commercial-crops/field-crops/. (Scroll down below the crop pictures and click on the corn tab. On the right, it should reveal a Variety Trial menu.)

Recently, BASF has added Poncho to its line of soybean seed treatments. This seed treatment may be useful for very early planted soybean, especially when planted into recently incorporated cover crop where the risk for seedcorn maggot is higher. In general, the vast majority of soybean is probably not going to benefit from an insecticidal seed treatment, and there is research that shows that they might actually make slugs a little bit more problematic. I included a table at the end of the 2020 recommendation guide that lists insecticidal seed treatments, if you are interested, it can be found here: https://www.udel.edu/academics/colleges/canr/cooperative-extension/sustainable-production/pest-management/vegetable-fruit-field/soy-beans/ under ‘Insect Control in Soybeans’.