Bollworm/Budworm catches for the week of July 12
| Location | CEW | TBW |
| Hardeman (Bolivar) | 1 | 0 |
| Fayette (Whiteville) | 0 | 0 |
| Fayette (Somerville) | 2 | 0 |
| Shelby (Millington) | 2 | 2 |
| Tipton (Covington) | 1 | 0 |
| Tipton (North) | 2 | 0 |
| Lauderdale (Golddust) | 6 | 0 |
| Haywood(West) | 6 | 0 |
| Haywood (Brownsville) | 0 | 1 |
| Madison (WTREC) | 62 | 1 |
| Madison (North) | 32 | 0 |
| Crockett (Alamo) | 0 | 0 |
| Crockett (Friendship) | 1 | 1 |
| Dyer (King Rd) | 0 | 0 |
| Dyer (Dyersburg) | 1 | 0 |
| Lake (Ridgely) | 8 | 0 |
| Gibson (Trenton) | 0 | 0 |
| Gibson (Milan Rec) | 0 | 0 |
| Carroll (Coleman Farm) | 0 | 0 |
I’ve received several reports, over the last two days, on fall armyworms (FAW) infesting double cropped soybeans. Almost every one of these calls were incidents of grass escapes and the lone exception was FAW migrating from a grass turn-row into v-stage beans. Somethings to keep in mind, vegetative soybeans can withstand 30% defoliation before yield loss and reproductive stage soybeans can withstand 20% defoliation before yield loss. Below is guide to help gauge defoliation levels.
If you do see armyworms it shouldn’t be automatically assumed that pyrethroids won’t be effective. We don’t fully understand why pyrethroids provided inconsistent control in 2021. Resistance is a possibility but overlapping generations causing mixing of various worm sizes resulting the appearance of poor control is another possibility. Also, since armyworms don’t overwinter in Tennessee and there is no evidence of reverse migration, the armyworms we experienced in 2021 won’t be the same ones we see in subsequent years. However, if pyrethroids do fail to control armyworms please contact your local county agent.
The FAW we are currently facing are the rice/grass strain, not the corn strain. They are impossible to distinguish visually but they are very host specific. Grass strain FAW almost always colonize grass, not soybeans, corn or cotton. Corn strain FAW almost always infest corn, soybeans or cotton not grass or rice. Another key difference is grass strain FAW are typically very susceptible to pyrethroids while corn strain are resistant. What happens when grass escapes occur in soybeans is the grass is controlled and FAW are forced off of a dying host on to soybeans. They don’t necessarily want to eat the soybeans but have no other options. If you have FAW in your fields and haven’t controlled grass yet, adding a pyrethroid would be a prudent step to save another potential trip. If you want other options outside of pyrethroids or are concerned they won’t work that list is here:
Acephate: 0.75 lb ai/ac,
Diamond: 6.0 fl oz/a,
Intrepid 4.0 fl oz/a,
Intrepid Edge 4.0 fl oz/a,
Vantacor 1.2 fl oz/a,
Elevest 5.6 fl oz/a,
Besiege 7.0 fl oz/a
Don’t automatically reach for the diamides (Vantacor, Elevest, Besiege) these products provide excellent FAW control but are costly. All of the above products will provide satisfactory control of FAW in soybeans.
Tarnished plant bug numbers seem to be all over the board in 2024. Some fields have one spray since square set and others have had upwards of five. Crop age and what’s neighboring your cotton play a large part of how intense plant bug pressure is over time. That being said, keeping an eye on square retention is the best gauge to determine how well your insecticides are performing. Most I’ve talked to have applied Diamond at least once since first bloom. Diamond shines when you catch early plant bug hatches often after large adult migrations during late squaring and we see a good ROI with Diamond around that 1st week of bloom timing.
Going into bloom, I don’t think neonics have a fit in any scenario. Every time we test a neonic sprayed after bloom its often one of, if not, the worst treatments in the test. Once you see a flower migrate to the Transform, Acephate, Bidrin treatments. Pyrethroids can be added in with OP’s to help increase control and acephate + pyrethroid can catch a few bollworms in the top of the canopy if you’re close to cut out (although our 3 gene cottons are doing a great job of controlling bollworms). Diamond should rotated around in the bloom mix also. Overlapping Diamond residual, usually spaced out every other shot, can help reinforce control of nymphs. I don’t like Diamond fb Diamond in succession. Diamond’s effects may take 7 to even 10 days to notice and sequential shots may not take full advantage of the residual it provides, but that’s situation dependent.
Thryvon bloom performance is on par with what we’re accustomed to seeing. Square retention is often better in Thryvon and plant bug numbers, especially nymphs, are lower. Insecticides seem to perform better in Thryvon for a couple of reasons. Less insects are typically easier to control, plant bug population growth is slower and we think the nymphs don’t settle in bracts/blooms like they do in non-Thryvon. Nymphs are constantly moving in Thryvon and the more they move, the higher likelihood they’ll encounter an insecticide. Final note, Thryvon has minimal, if any, activity on stink bugs and if you’ve gotten by without using a broad-spectrum insecticide mid to late bloom, I would add an OP or pyrethroid to clean up any building/lingering populations.
The Tennessee Top Bean soybean yield contest sponsored by the TN Soybean Promotion board and coordinated by UT Extension is open for entries now until September 1st for the 2024 season.
This year’s County Standardized Trials, Wheat Program tested 23 varieties of Soft Red Winter Wheat in 10 locations. Seven of those locations where used to compile our variety recommendations for the 2024 fall planting. Over all, yields across varieties and locations averaged just over 76 bu/ac, with an average of 10.4% moisture and 55.1 lb testweight.
Thank you to all the producer who put these trials out and the County Agents who organized and oversee these variety plots. Also, a special thanks to our cooperating companies who supply seed and genetics to test in our environment. Wheat yields have increased dramatically over the years, better genetics and breeding programs along with state and local testing are proving to add weight to the combine and increase profits for wheat growers in TN.
If you are interested in having a County Standardized Trial (Corn, Soy, Cotton, Wheat) on your farm, contact your local County Extension office for more details.
This Fall, contact your seed suppliers and request wheat seed from the list above with confidence from our unbias variety testing program.
Over the past couple days, I’ve gotten a few reports of fall armyworms in pastures on the Mississippi/Alabama border with Tennessee. Tennessee will still have armyworms that migrate North and infest pastures, food plots and the occasional yard every year. However, the situation that happened in 2021 was a very unique event and will not occur yearly. That being said, reports of armyworms in 2024 are roughly two weeks earlier than what we typically see.
Fall armyworms don’t overwinter in Tennessee and populations migrate North from Texas and Florida every year. The difference in 2021 vs 2023-24 is the conditions that were occurring in April and May in South Texas. Texas experienced a warm and unseasonably wet spring that allowed for the proliferation of extremely large numbers of armyworms. Large numbers of moths plus ample food supply in pasture grasses, fallow grasses, yards and pretty much anywhere that had grass allowed this “army” to make its way North. Texas experienced outbreaks first followed by Louisiana, Arkansas, Mississippi then Tennessee with the moth flight culminating, in Canada, in November. I ask my colleagues, in Southern states, weekly if they are seeing any armyworms or anything resembling what happened in 2021 and the answer has consistently been no. My colleagues in Arkansas are getting calls about armyworms in rice and pastures but nothing even close to what was experienced in 2021.
If you do see armyworms it shouldn’t be automatically assumed that pyrethroids won’t be effective. We don’t fully understand why pyrethroids provided inconsistent control in 2021. Resistance is a possibility but overlapping generations causing mixing of various worm sizes resulting the appearance of poor control is another possibility. Also, since armyworms don’t overwinter in Tennessee and there is no evidence of reverse migration, the armyworms we experienced in 2021 won’t be the same ones we see in subsequent years. However, if pyrethroids do fail to control armyworms please contact your local county agent.
Going forward, pasture treatments should be considered when armyworm populations exceed 3 to 4 worms per square foot. If fields are ready or near ready for cutting, harvesting is suggested rather than applying an insecticide. Producers may watch for the presence of birds in a field as an indicator of armyworms. This method should not be the only one used to check for armyworms because this indication often is too late to avoid field injury. Early signs of infestations by small larvae cause plants to have a “window-paned” appearance. This is due to the larvae’s inability, at small sizes, to chew completely through the leaf blade leaving the upper epidermis intact. Large areas of window panning will give fields a frosted appearance. Ideally, scouting should be initiated in late July to early August without the presence of birds or frosted patches appearing so infestations can be caught early. When scouting during times when armyworms are not feeding (midday) be sure to dig through the thatch layer and check the base of plants. Detection of frass (insect excrement) is also a sign that armyworms may be present in a field.
Information on grazing restrictions, application rates and insecticide choice can be found below.
The take home is scout early and often for armyworms in pastures, hayfields and turf areas. It may be prudent to initiate scouting earlier than we’re accustomed to catch any early infestations that may slip by.
With the wide range in planting dates, we have soybean and corn at all different stages which will influence disease onset and fungicide considerations. Continue reading
Serious infestations of goosegrass, junglerice and barnyardgrass have proven to be way too persistent in many cotton and soybean fields (Picture 1). Many are getting frustrated with the lack of control seen with tankmixes that contain glyphosate and/or clethodim or quizalofop. Some have asked if maybe some of these grasses have developed resistance to glyphosate, clethodim and quizalofop. Continue reading
