AgFax Southern Grain - Louisiana

by AgFax Media LLC, AgFax.com

OVERVIEW

Bollworm/corn earworm moth counts continue to increase in parts of the South. In some areas treatments are being made in soybeans, particularly where plants haven't closed the canopy.

High, early levels of pyrethroid resistance are turning up in Virginia's monitoring program. See comments by Ames Herbert.

Varying mixes of worms are either being monitored or treated in soybeans in both the Southeast and Midsouth. Depending on the area, this might include earworms (yellowstriped, beet and fall), garden webworms or saltmarsh caterpillars.

Stink bug treatments are being made in soybeans on a scattered basis, although probably more intensely in Louisiana. Redbanded stink bugs are the predominate species in Louisiana soybeans at the moment.

Kudzu bugs continue their migration into Midsouth soybeans. Extension personnel are urging farmers and crop advisors to delay spraying until fields reach the generally accepted threshold – one immature per sweep.

Dicama injury on soybeans continues to be reported, mainly in the Midsouth. Connect to a related DTN article in our Links section.

Corn harvest has started in the lower South on a limited and specific basis. A small amount of short-season corn was cut last week in eastern Mississippi. But several of our contacts in the lower South said some harvest might begin next week in a few early-planted fields.

Corn leaf disease is on the light side, our contacts continue to report. In certain cases where it's turning up the corn is past the point that it would matter much.

Sugarcane aphid treatments are being made on grain sorghum. Threshold levels have been found as far north as upper North Carolina. 

LOUISIANA CROP REPORTS

Sebe Brown, Northeast Louisiana Region Extension Entomologist: "Redbanded stink bugs have definitely picked up in the northern parishes and guys have initiated treatments. People in south and central Louisiana already have been fighting them. In places, people also are dealing with corn earworms (CEW) in soybeans.

"Some folks who are finding CEW think they can use a pyrethroid by itself, but a few guys tried that and ended up with complete disasters. The treatment didn't work and in some instances it made things worse because it took out beneficials, so even more worms are present now.

"If you're close to threshold or already have heavy CEW numbers, go with a dedicated product like a diamide. Don't assume you can run a high pyrethroid rate and clean them up. Keep in mind that Louisiana leads the nation in the percentage of bollworms that are resistant to pyrethroids. Research and surveys continue to show that.

"In grain sorghum, sugarcane aphid infestations are spreading over more areas now. However, a lot of people are staying on top of this, and SCA appear to be mostly under control. No midge issues in grain sorghum. I know that some people have sprayed for them, but a lot of guys who are scouting for midge aren't finding treatment levels. That's not to say pressure won't build later, but populations at this point are mostly light.

"CEW are definitely picking up in grain sorghum. The headworm complex also includes some fall armyworms and sorghum webworms. A few farmers will be cutting grain sorghum in the next couple of weeks. Some desiccants have probably been applied by now but I expect more of that to start this week."

Harold Lambert, Independent Consultant, Innis, Louisiana: "Our oldest corn, mostly dryland, is just now at black layer. Our youngest is dented and probably at 10% to 20% starch. Our early MG IVs that were planted early will be harvested soon and sugarcane will be planted behind them. They're at R6. We've had to treat them once for stink bugs and just a few fields have been sprayed a second time. Our other soybeans range between R3 and R5. We've applied a fungicide and we also had to treat in places for bollworms."

Hank Jones, C&J Ag Consulting, Pioneer, Louisiana: "We're either done with watering corn or are on the last irrigation. I found some black layer late last week in irrigated corn planted in the last of February and first week of March. Our April-planted corn is just into dent and looks pretty good. We have at least another couple of waterings in it.

"Enough southern rust is out there that we can easily find it, but most of that acreage is deep enough into dent that it's not a concern. Some hybrids had enough corn leaf blight and rust to make them look kind of ugly, but they're 10 days past hard dent and we don't anticipate problems.

"In soybeans, we made our first recommendation this year for a stink bug spray. Those beans are in Tensas Parish, and late last week we could find stink bugs, maybe 2 per 100 sweeps. But by Monday (7/11) we were at threshold for redbanded stink bugs. They moved in like an army and the brown and green stink bugs moved out. Those beans were at R6, so by now we would expect to treat for something.

"The types of insects we're finding are very much tied to the field's growth stage. When soybeans are filling pods, we're finding stink bugs. Where beans are at R2 to full bloom we'll probably have bollworms. We'll spray about 250 acres of beans this week for bollworms.

"Beneficials have been so good this year that I've got to wonder if they've helped hold down the numbers. The beneficial populations aren't high enough to buy the whole season but enough are in the beans to give us 7 to 10 more days before a treatment would be required."