Category Archives: Pasture

Fall Armyworms Appearing in Tennessee

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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 wormageddon that happened in 2021 was a very unique event and will not occur yearly.

Fall Armyworms in Sweep a Net
Fall Armyworms in a Sweep Net

Fall armyworms don’t overwinter in Tennessee and populations migrate North from Texas and Florida every year. The difference in 2021 vs 2022-23 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 colleague, Dr. Nick Bateman, is getting calls about armyworms in rice 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. https://extension.tennessee.edu/publications/Documents/PB1768.pdf

One final note to homeowners, don’t fall for armyworm preventative lawn treatments. Most lawn products that are utilized for fall armyworm outbreaks, especially foliar sprays, have limited residual efficacy and shouldn’t be applied if armyworms aren’t present. Insecticide residual, even in systemic products, grows out with your grass. If you mow your lawn on a regular basis the residual needed to control armyworms is mowed off and new growth may not be protected. Applying an insecticide for an insect that isn’t there or may never show up, isn’t IPM and is a waste of money. Your county agent is an excellent resource for information pertaining to armyworm control in home lawns and pastures and won’t try to sell you anything.

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Managing Knotroot Foxtail in Pasture

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This is an update to a post run several years ago. You can also download a print-friendly PDF version of this article here, Knotroot Foxtail Facet L Fact Sheet-Revised.

Knotroot Foxtail
Knotroot foxtail is a warm-season perennial grass that is also known as knotroot bristlegrass or simply perennial foxtail. It is native to the Americas and can be found throughout Tennessee in hay fields, pastures, lawns, roadsides and waste sites.

Knotroot foxtail is difficult to control. Some of the most serious knotroot foxtail problems are in bermudagrass hay fields. The Continue reading

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Field Crop Insect Management Recommendations (PB 1768) Available Online

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The 2020 version of PB 1768, Insect Management Recommendations for Field Crops (and pasture), is now available. The guide has gone through substantial revision this year and closely matches the content on the mobile friendly Disease and Insect Field Guides at https://guide.utcrops.com/. Hard copies will be available soon and distributed through county extension offices and at various educational meetings.

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UT Insect Management Guide for Field Crops

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The 2018 Insect Control Recommendations for Field Crops (cotton, corn, soybean, wheat, sorghum, and pastures) can be found online on UTcrops.com.  Insect and disease management recommendations for cotton and soybean are also available on the mobile-friendly Field Guide website at http://guide.utcrops.com/.

Suggestions: Add the  UTcrops News Blog to your home screen for easy access to all these resources.

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UT Extension County Meeting Schedule, January/February

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In addition to the East, Middle and West TN Grain Conferences and the Cotton Focus event, UT Extension is hosting a series of meetings to be held throughout the state to prepare growers for the upcoming season. These meetings will focus on variety selection, insect and plant disease management, weed management, and other current crop production topics.

Below is a list of the production meetings to be held in January and February. Please contact your local UT Extension office for more details on time and location. Continue reading

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Fall Armyworms Look to Make and Early Start (again)

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It seems that fall armyworms have gotten a running start in recent years. This species does not overwinter in Tennessee, but it may survive warm winters in the extreme southern areas of coastal states during mild winters. It migrates into Tennessee each year. Often, fall armyworms don’t show in substantial numbers until late July or August. However, they are being found Continue reading

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2017 Insect Control Recommendations for Field Crops

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pb1768The University of Tennessee’s 2017 Insect Control Recommendations for Cotton, Soybean, Corn, Sorghum, Wheat and Pastures (PB 1768) is now available online.  Once available, hard copies will be distributed at Cotton Focus, grain conferences, and other crop production meetings.

Some features you may have overlooked in the back of the book include:

  • Listing of insecticide classes (mode of action) and registration numbers
  • A list of common “generic” trade names for various insecticides
  • Tables ranking the relative efficacy of insecticides on common pests
  • Tips to minimize pesticide effects on pollinators
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