The two best fall-applied options for ryegrass and poa in wheat are Anthem Flex and Zidua. Pyroxasulfone is providing the grass control in both these herbicides. Anthem Flex can be applied as a true PRE right behind the press wheel. Keep in mind there is some chance of wheat injury from this new use pattern if a rain occurs shortly after planting. As such, if rain is in the forecast wait and apply it later as a delayed PRE or early POST. Continue reading
Wondering what’s been making your soybeans sickly? Come to The University of Tennessee Soybean Disease Field Day, held Tuesday, Sept. 12th, at the Milan Research and Education Center. Registration will be from 8:30-9:00 AM with the tour beginning at 9 AM and concluding with a box lunch. Preregistration is not required. Pesticide re-certification and CCA points will be available. Continue reading
|Dyer (King Rd)||12||0|
|Gibson (Milan Rec)||0||0|
|Carroll (Coleman Farm)||8||0|
Numbers are consistently going down across West TN and this is the last week for trap catches.
I’ve received a few calls this week on corn earworms (bollworm/podworm) showing up in fields across Tennessee. UT’s threshold for earworms, in beans, is based on sweep net sampling, crop value and control costs. The table below outlines the threshold based on the above factors.
Crop value is on the left-hand side, control costs are the 3rd row from the top and numbers beneath control costs are earworm numbers per 25 sweeps. The spot price of beans for (8/31) is $13.75 and control costs can vary from $10 to $16, depending on product choice, so the threshold in 25 sweeps would be 5 to 6 earworms per 25 sweeps. As crop price and control cost changes so does the number of earworms in our threshold.
Moths are typically attracted to later planted, more open canopy fields. However, earworms can be found in any stage beans. Insecticide choice depends on a few factors. If earworms are at or near threshold, acephate (0.75 lb/a) plus a pyrethroid is a cheaper option that provides acceptable control. This option runs the risk of flaring other pests (loopers, mites) and fields need to be rechecked 4-5 days after application to makes sure adequate control was achieved. If worms are above threshold safer choices would be Vantacor (1.2 fl oz), Elevest (5.0 fl oz), Besiege (7.0 fl oz), Intrepid Edge (4.0 fl oz) or Blackhawk (2.0 oz). The diamides (Vantacor, Besiege, Elevest) will have the longest residual control but many earworm issues in TN beans are solved after one application.
Another, more nonconvention option is Heligen (1.0 – 1.5 fl oz). Heligen is earworm specific and doesn’t have a fit on every acre. Applications should be initiated on small larvae at half a threshold (typically 2 – 4 larvae in 25 sweeps). Heligen is a virus that spreads throughout the field via infected larvae and requires some patience and knowledge of infection symptomology.
One final note, this product should almost be looked at as a preventative not a curative product. However, worms have to be in the field for the virus to infect the target and replicate causing an epizootic. Large populations of earworms, at or above threshold, need a conventional insecticide.
I’ve had several questions over the past two weeks about how many heat units we have accumulated and how this compares to our average year. As of August 28th, we have accumulated 1,974 DD60s since May 1. We’ve broken from the 30 year average trend line several times throughout the year; May was considerably warmer, June pulled us back to the average trend line, and although we have been rolling above and below the line from the end of July through August, as of August 28th, we are within 15 heat units of the 30 year trend line; on average, by August 28th, we accumulate 1,961 DD60s. As you look at the above graph, you may notice these breaks with the trend line are ever-so-slight. Keep in mind rate of change is important. If you zoom in on several of the regions highlighted above, you can see how our weather this year breaks from the trend line before rejoining it throughout the season. Continue reading
Soybean cultivar selection in the Mid-southern U.S. has shifted toward early maturing, indeterminate maturity group (MG) 4 varieties. This shift has increased the adoption of harvest aid application in these environments. Leaf retention and green stems and pods in earlier maturing, indeterminate varieties after physiological maturity can delay harvest. Application of harvest aids also assists in late-season weed control and may allow producers to achieve earlier crop delivery at an above-base premium. Continue reading
|Dyer (King Rd)||28||0|
|Gibson (Milan Rec)||1||0|
|Carroll (Coleman Farm)||17||0|
The 2023 Cotton Tour will be held Sept. 13, 2023 at the West Tennessee Research and Education Center (605 Airways Blvd, Jackson, TN 38305). Pesticide recertification and CCA points will be available. Lunch will be provided. We will also be touching on a few other commodities (soybeans, corn). An agenda will be posted to the blog in the coming weeks. Look forward to seeing you there!