AgFax Cotton - Louisiana
By AgFax Media LLC, AgFax.com
OVERVIEW
Bollworm activity has widened and treatments have been going out on a broader basis. Some slippage has been noted in triple-gene cotton in one location in central Louisiana. See comments by Sebe Brown.
Plant bug treatments continue. In places, numbers have backed off considerably. But in other locations, they remain a factor.
Spider mites persist in northeast Arkansas and the Missouri Bootheel. See comments by Gus Lorenz and Scott Gifford. Aphids also still require attention in places.
The crop is speeding along by most accounts. Our contacts continue to say that their cotton appears to be running ahead of schedule.
LOUISIANA CROP REPORTS
Steve Schutz, Ind. Consultant, Coushatta, Louisiana:
:We badly need rain. It's been too late for dryland corn and it's probably too late for a lot of soybeans. Cotton's potential will decline if we don't get rain in the next 10 to 15 days.
"About two-thirds of our cotton has cut out but some later fields are still going. It's hard to say for sure, but cotton seems to be running about 3 weeks ahead of schedule, whether that's a positive or a negative. Some cotton looks good and some looks really, really good. Much of this crop is holding plenty of bolls.
"Without timely rains, some cotton didn't reach the height we wanted, but it still has a good boll load. We may have overdone the Pix in certain cases, but I wouldn't change a thing. Even with ample amounts of Pix, I still have fields that are chin high but only got 60 pounds of nitrogen and haven't had any water in 3 weeks.
"So far, no target spot has developed, and that may be partly due to taking an aggressive approach with plant growth regulators. We had a horrible year with target spot in 2017. One client probably lost 30% of his yield last year due to target spot and he's not upset at all that we may be restrained growth too long this year.
"We've had some bollworms. Pressure hasn't been heavy but numbers have been dribbling along, which in some ways might be more expensive to manage. We've only applied Prevathon or Besiege. We're about to hit 14 days with those treatments, which is okay. The worst I've ever done was 11 days and the best was 17 days.
"We've had to treat aphids. Usually by now, they're out of the picture, but I think the winter was particularly hard on one key predator and the fungus hasn't developed yet. More spider mites are in cotton, too. Usually, we may have to spray 10% to 15% of our cotton. This year, it's more like 15% to 20%. So far, results have been good with one shot of abamectin.
"We've had to spray everything for plant bugs once, with a second application needed in places."
Sebe Brown, Northeast Louisiana Region Extension Entomologist:
:Things have taken a turn for the worse with bollworms in certain areas. In a sentinel plot in central Louisiana, fruit injury in Bollgard 2 (BG2) went from 8% to 60% in a week, with plenty of live worms. In Bollgard 3 (BG3), fruit injury went from 1% to 18% and we were seeing 1- to 2-day-old worms and a few at 4 to 5 days.
"In BG2 and WideStrike 3 (WS3), we found fourth instar larvae walking through it. The threshold for fruit injury is 6%, so this is pretty rough. In that same area, we received a report of 30% injury in WS3, with large worms hanging out of bolls, squares and flowers. That WS3 was in a commercial field and it was sprayed today (7/24).
"Let me emphasize that all this happened in one location in central Louisiana and it's nothing that we'd call widespread. In northeast Louisiana, pressure is moderate but damage is light. That's also the case in Tensas Parish.
"How much of this might be due to potential resistance or lower toxin expression is an open question. With drought stress, expression may falter. A lot of factors go into whether damage occurs and you can't always predict where populations will walk through any given technology. But at least in that location, it looked like none of the technologies were holding.
"I don't want to scare growers, but everyone needs to take into account that we're finding this. You can't stop scouting. In central Louisiana, you certainly can't turn your back on worms yet. In just 6 days, we went from bad to a disaster.
"Plant bugs are picking up again in certain areas. I think a lot of the late-planted April corn is drying down fast with this hot weather, which has triggered another mass migration into cotton. A lot of alternate hosts are drying down, too, and cotton is the only thing still blooming.
"Spider mites are showing up in a few places, mainly where guys have gone with harsher insecticides, which would favor mites. Growers are tired of breaking the bank with plant bugs, so they've shifted to these cheaper materials and the mites are a result."
Ashley Peters, Peters Crop Consulting, Crowville, Louisiana:
:We've over-sprayed all of out dual gene cotton and that seems to be holding so far. I don't think the pressure is as bad in my general area as people are reporting in other places. We're not seeing massive egg lays or eggs deposited on top of eggs.
"We went with Besiege or Prevathon. We may have some cotton at or close to cutout and we might be able to get by with one application. Plant bugs are just kind of there. The worst places have been around corn, and we have had a tough time with them in a couple of places. Overall, though, I think we did a good job of keeping them in check.
"A lot of cotton already is at 5 NAWF or less, and this may be an early crop – whatever 'early' is anymore. A little corn has been cut in the area and some of my guys will start this week."