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“Sugarbeet Report” presented by NDSU Extension, features growing tips from NDSU sugar beet specialists and researchers.
This is the Sugar Beet Report, bringing you the latest information from NDSU throughout the sugar beet growing season. The peak of sugar beet root maggot is behind us. But what is the impact, and what other insects are a threat to the sugar beet crop? Mark Botel, NDSU Extension Entomologist, has the breakdown and the hit list of insects still causing problems. Mark, your counts have maggot populations lower this year. Is that accurate?
Mark Boetel:So our counts would say, yes, significantly lower numbers were captured on the sticky state traps that we had throughout the valley, and certainly that's reason for optimism, but, we did have several days of windy conditions during about that time when peak flies should have been occurring, so thinking possibly the numbers may not reflect what was actually out in some of those fields that the winds may have kept the root maggot adult fly lower to the ground, may not have been caught on the stakes as they might have otherwise been. So we may possibly have had more flies than what the traps showed.
Bruce Sundeen:Does that raise questions about what to expect next year?
Mark Boetel:Yes. I believe it does. Certainly, it is a question mark. We could still use this year's hot spot data for where we expect similar conditions next year, or where we should expect the hot spots anyway. We just have to also remember that when I build a forecast for the subsequent growing season, that we also look at root ratings in commercial grower fields. So I'll be going out late summer, I do that each year and collect root samples, and it sort of ends up being kind of a ground truthing. We'll rate those for root maggot and larval feeding injury, and that's what we're all really trying to manage, and essentially functions as a ground truthing for what we think we saw as fly activity, and then what what actually survived and made it through, and the population levels that caused injury, and that will be our population for next year. And I'll use that to develop that forecast and then that'll be presented at the various winter grower meetings and the Sugar Research reporting session as well. So I encourage people to attend those events.
Bruce Sundeen:Mark, now that we're past the point of managing root maggots, what other pests should sugar beet growers be watching for now?
Mark Boetel:We're beginning to see some lygus bug activity, and I expect that to increase for the next several weeks. I'm hearing the most activity reports from the MnDAC and Southern Min Cooperative growing areas, but I wouldn't doubt that we may see that a little farther northward as well, so that's something to watch for. Grasshoppers, I haven't heard a whole lot, but I'm seeing immatures out there now that suggest that they are certainly out there. We'll just see what happens with populations in the next few weeks with them. The beets are pretty far along now, so one thing to remember, we don't need to necessarily go out there and spray when we see the first grasshopper or ligus bug, that kind of thing, especially chewing insects like grasshoppers, maybe blister beetles, is that the beets have a lot of foliage now. It takes a fair amount of defoliation to really justify economically the use of an insecticide. And then one other important thing as we approach August, be aware of the pre harvest interval on the labeling of their insecticide product.
Bruce Sundeen:Well, Mark, what about a shameless plug for your upcoming plot tour?
Mark Boetel:I would love to do that. Yes. We had a good one Tuesday of this week at Saint Thomas. We've had a practice run there, and now we're gonna do the big show at NDSU's experiment farm there in near Prosper, North Dakota. It'll be on Tuesday, July 30th. We have a 10 o'clock sharp start, and we'll have a compendium of presentations from Weed Science, Doctor. Tom Peters, as well as Eric Branch with Sugar Beet Plant Pathology. And so I'll be doing insect management presentations, and we'll have demonstration plots there as well. People could see what products are working to control springtails. We'll also wrap that up with a sponsored lunch, so free lunch.
Bruce Sundeen:Thanks, Mark. Our guest has been Mark Botel, NDSU Extension Entomologist. This is the Sugar Beet Report, bringing you the latest information from NDSU throughout the sugar beet growing season.