Damon Smith, Extension Plant Pathologist
Department of Plant Pathology
University of Wisconsin-Madison, College of Agricultural and Life Sciences
Here is a schedule for the upcoming Pest Management Update Meetings, one of the fall meetings Damon Smith references in this podcast.
Total Time – 3:10
0:13 – Overview of this corn crop season
1:14 – What to do if suspect corn disease
2:10 – Where to test for mycotoxins
2:22 – Advice for next year
3:00 – Lead out
Lorre Kolb: Challenges to Wisconsin’s corn crop. We’re visiting today with Damon Smith, Extension Field Crops Plant Pathologist, Department of Plant Pathology, University of Wisconsin-Madison/Extension in the College of Agricultural and Life Sciences and I’m Lorre Kolb. Damon, what are you seeing in Wisconsin’s corn crops?
Damon Smith: Yeah, it’s been a challenging year. First, early in the season we had gray leaf spot come in, that started in June. We typically don’t see that particular disease at least that early in the season but it got an early foothold here and sort of set us up for maybe some more disease issues just because it stressed the plant a bit. We then saw a newer disease tar spot move in and that had a really had a substantial impact, especially in the southern and southwestern part of the state here. However we are seeing tar spot moving up into the central part of the state, but I think it’s late enough in that central area that it will have minimal yield impacts. In the southwest side, the tar spot epidemic, combined with the gray leaf spot epidemic have taken yields. We’re seeing yields off by 50 percent or more in some fields and then we had a northern corn leaf blight epidemic move in late in the season here, so this trifecta of diseases is just really really impacting the corn crop, causing standability issues and secondary issues with ear rots and probably some mycotoxin accumulations.
Lorre Kolb: So what should farmers do it they suspect any of these diseases?
Damon Smith: You could send samples into the clinic, although the season’s getting pretty late now to find good samples. But if you’re curious and just want to confirm which diseases you have to make some decisions on your hybrid choice for 2019, I think that’s a good thing to do. The other thing is if you can get out to a hybrid trial where there’s multiple hybrids just being tested side-by-side it will be readily apparent which hybrids have performed well and choosing a hybrid that still green this time of year I think is a really important thing to do. And then testing the crop as it’s coming out of the field, especially for mycotoxin issues. We have chopped some silage corn trials and we’ve found quite a bit of natural Gibberella, ear rot. That amount of Gibberella could cause vomitoxin issues in finished grain and also in silage and so it’s really important that farmers test both grain and silage to see what toxin levels are there.
Lorre Kolb: And how do they do those tests?
Damon Smith: In our Pest Management in Wisconsin Field Crops Book, A3646, there’s a table which has a list of mycotoxin testing labs.
Lorre Kolb: Advice for farmers as the season is ending and going into next year.
Damon Smith: Be diligent on which hybrid seed you’re going to buy for the 2019 season. Also get to your fall and winter meetings this year. We’re going to have a lot of good information. We’re in the process of pulling in some hybrid ratings, we’re also pulling in fungicide efficacy data; we’ll have that all available at fall and winter meetings and so we should have some good research-based updates this winter. Having that information in hand moving into 2019 is going to be important because these diseases are able to overwinter here and so I think we’re going to maybe see some of this again next year in 2019.
Lorre Kolb: We’ve been visiting with Damon Smith, Extension Field Crops Plant Pathologist, Department of Plant Pathology, University of Wisconsin-Madison/Extension in the College of Agricultural and Life Sciences and I’m Lorre Kolb.