We are just compiling the Extension fall soybean weed surveys; it is bad again with marestail and giant ragweed leading. The big news this year is that resistant marestail is statewide — the whole state now looks like the southwest has for the past 10 years. OSU Weed Specialist Mark Loux says to better manage resistant marestail:
- Do spray a fall treatment for next years no-till soybeans.
- Keep it simple. Don’t bother with a residual in the fall, save those dollars for the spring application.
- Timing that generally works well is late October into early November. Although I like to wait until after we have had a rain to settle the corn stalks and spruce up the weeds a little.
Fall soybean insects
They are getting worse. Maybe it was the dry fall or the wet August, or just a shift in insects but as I was harvesting I saw more seed damage than I have ever seen before. I don’t think we scout much after about mid-July so we probably missed the increasing levels of these late season insects on soybean. Late season insects I saw were grasshoppers, bean leaf beetle and more widespread stinkbug. Think now about later scouting for next year, and how you will manage soybean insects.
Variety and hybrid selection — it matters. Choose a variety with excellent protection from disease. Did you see frogeye in soybeans this year or Gray leaf spot in corn? Comb through your company seed trail yield data and look through the seed catalogs. And as quickly as it is posted, look through any unbiased yield data you can find — including OSU’s corn and soybean performance trials. Watch the C.O.R.N. newsletter at http://corn.osu.edu for when they get published.
Did Soybean cyst nematode hurt yields this year? Probably, so from Anne Dorrance and Terry Niblack our OSU Plant pathologists we get these suggestions:
- This year’s early harvest provides the perfect opportunity to take a look at the SCN populations in your fields. We know that the state is now “polluted” with SCN, fortunately most of those fields are at very low levels — which is where they should be kept.
- So it is time to sample! We recommend sampling in the fall — because in most cases this is what the population will be in the spring.