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Row Crop Update (6/14/19)

Corn

We have a lot of older corn in the county that has put on a nice ear and we’re starting to see a lot of silks turning brown. The rain and cool weather this week has certainly been a relief for all our crops, especially corn. I have been out and have only seen a few fields with Northern Corn Leaf Blight, but not enough to be alarmed about. There has also been no reports of Southern Corn Rust in the state. With that being said, a fungicide is not urgent so far this year. I am seeing a fair amount of stink bugs, but not much damage from them.

Corn at late R2 (blister stage)/early R3 (milk stage)

Cotton

Thrip damage is the worst I have seen this year. After talking with Dr. Phillip Roberts and Mark Freeman, the reason for that is because there was a mass movement of thrips into cotton from nearby vegetation that normally would hold them over and keep them off the cotton. The super hot, dry weather killed a lot of that natural vegetation, and the thrips moved into cotton that was lush and green. With the rain we have received, it definitely has helped the situation, but this young cotton still needs monitoring closely. Some growers have sprayed a lot of acres with Orthene, especially fields where AgLogic was not used, or dryland fields where AgLogic was not activated. Going forward on young cotton, remember the thresh hold is 2 to 3 adults per plant and immatures present. Other than thrip damage and a little herbicide damage, the cotton has really started to grow this week. As a lot of cotton is starting to square, be sure that we’re keeping an eye out for tarnished plant bugs.

The pictures below are from the same field, one treated with AgLogic and one without.

Thrip damaged cotton with no AgLogic

with AgLogic

Peanuts

Two things we are looking heavily for right now is lesser cornstalk borers and white mold. There have been reports of both around the state, and I want us to be prepared. Extension Entomologist Dr. Mark Abney:

What should growers do about LCB? The most important thing a grower can do is monitor fields regularly and take appropriate action if/when infestations are discovered. Three insecticide active ingredients are recommended by the University of Georgia for LCB management in peanut: chlorpyrifos, chlorantraniliprole, and novaluron. Chlorpyrifos (Chlorpyrifos 15G) can only be applied as a granular product banded over the row. It requires rainfall or irrigation for activation, and applications are often followed by outbreaks of caterpillars and/or mites. Chlorantraniliprole (Prevathon) and novaluron (Diamond) are applied as broadcast foliar sprays. Rainfall or irrigation after application may improve efficacy, but I have no data to support this, and both products have provided good control in UGA trials without additional water.

Severe LCB infestations are not common in irrigated peanut after the vines have lapped the row middles IF adequate irrigation is applied. However, LCB is often found in irrigated fields (especially those with sandy soils) prior to row closure when environmental conditions are favorable. LCB caterpillar feeding in the crown of seedling plants can reduce yield even if adequate water is available later in the growing season. It is important to remember that while LCB does not survive well in moist conditions, one or two rainfall events will not eliminate an established population, and we will probably not be able to “irrigate LCB away” prior to row closure.

The two mistakes that are most likely to be made when LCB infestations are on the rise are:
1. Treating fields with an insecticide when no insects are present. No matter how bad LCB gets in 2019, it will not be in every field.
2. Failing to treat or treating too late when thresholds are reached.
Scouting is the best way to avoid these mistakes. It is hot and dry and there are lesser cornstalk borers in some of our peanut fields, and we cannot do anything about any of that. What we can do is stay calm and make wise decisions that will protect our peanuts and maximize our return on investment.

Extension Plant Pathologist Dr. Bob Kemerait:

2019 seems to be a PERFECT year for white mold on very young peanuts.  Early outbreaks of white mold typically occur when there is A) unseasonable HOT weather early and B) there is some moisture available, generally just below the soil surface.

EARLY SEASON WHITE MOLD:  Can be managed with use of in-furrow applications of a product like Proline, though Proline is much more effective when the full rate is BANDED over the row 3-5 weeks after planting.  Growers can also begin their white mold program earlier, for example, using Priaxor at 45 DAP, perhaps even bumping the rate from 6 to 8 fl oz/A), starting the Elatus program early (7.3 oz/A at 45 DAP), or most likely, tank-mixing a fungicide effective for white mold control (typically tebuconazole, 7.2 fl oz/A) with the leaf spot applications at 30 and 45 days after planting.  It is critical that once growers reach 60 DAP, they remain aggressive and vigilant with the “backbone” portion of their white mold program, whatever program that might be.

Soybeans

Dr. Kemerait:

We have Asian soybean rust in kudzu patches across the Coastal Plain.  If the soybeans were mine, I would absolutely plan to apply at least one fungicide to them and maybe more beginning sometime between first bloom and early pod set.  Absolutely I would…