Fall Armyworm in Pasture and Hayfields 2021

We have had numerous reports of fall armyworm egg masses in pastures and hayfields in KY in mid-August and now significant damage is occurring from the caterpillars across the state. Therefore, keep a close watch on your pastures/hayfields for these armyworms over the next few weeks. If you have 2-3 caterpillars per square foot or more, then you should consider spraying. In other words, these numbers will likely mean you will have considerable damage to late summer/fall growth in your pastures and hayfields.

One of the most effective insecticides is Besiege from Syngenta.  This insecticide has dual modes of action and is systemic resulting in a higher chemical cost per acre ($25 per acre).  A considerably less expensive option ($5 per acre) that can be effective on smaller armyworms (less than ¾ inches) is Warrior II from Syngenta.  Both insecticides have a 0-day grazing restriction and a 7-day harvest restriction for hay. Note: fall armyworms are easiest to kill when small and pyrethroid (pyrethrin) insecticides like Warrior (or generic versions of this product) are effective at this stage and considerably less expensive.

An potential alternative to insecticide application for hay crops near harvest stage, is to mow the crop IMMEDIATELY.  Unfortunately, waiting 2 or 3 days for good curing conditions is not an option since armyworm defoliation is so rapid.  Once cut, the conditions in the mowed forage become less conducive for the armyworm. 

Please see recent articles in the Kentucky Pest News from our entomologists in Lexington (Ric Bessin and Jonathan Larson) and in Princeton (Raul T. Villanueva and Zenaida Viloria) for more information on fall armyworm.

~ S. Ray Smith, Chris Teutsch, Raul Villanueva, and Jimmy Henning

Armyworm Update —Aug 30

Armyworms have been steadily moving across Kentucky and will likely be with us until frost.  The lifecycle of armyworms is approximately 20-30 days (from eggs, to worms, to pupae, to moths, to eggs again), but it is important to remember that the population is NOT synchronized.  So new armyworms could be emerging daily until frost.  We wanted to share a few observations and thoughts with you.

We are observing plenty of egg laying from the current crop of armyworms.  This is a good indication that they will be a persistent problem until frost.  Alfalfa and clover seem to be a preferred food source, but there are also reports of devastated hayfields and pastures. We expect established hay and pasture stands to  grow back normally, but may be weakened.

Controlling re-infestations in alfalfa is critical as we move into fall.  As you know, allowing alfalfa to replenish carbohydrate reserves in the taproot prior to fall dormancy is important for persistence and growth in the spring.  So, scouting and insecticide application when the economic threshold has been reached is critical to the the long-term health of alfalfa stands.   

If you are establishing new forage stands this fall, it is critical that they are closely monitored, and insecticides are applied as soon as the economic thresholds have been reached. New seedings will be extremely susceptible to fall armyworm damage since they do not have an established root system and will not likely recover. If you are stockpiling cool-season grasses for winter grazing, it will be important to closely monitor growth for armyworms and apply insecticide once the economic thresholds have been reached.  

~ Chris Teutsch and Ray Smith

Pub of the Month: Grazing Alfalfa

 Alfalfa has long been recognized as the premier forage crop around the world. Though grazing alfalfa is not a common practice in most of the United States, it is widely practiced in other regions, and certainly feasible in the United States.

This publication reviews the important considerations for grazing alfalfa and alfalfa/grass stands for meat and milk production. It also shows the benefit of alfalfa in sustainable pasture systems and highlights how alfalfa can be used for grazing by all livestock including sheep, goats, and horses. The new publication also provides a realistic overview of the benefits and challenges of grazing alfalfa and assists producers in determining if this high quality forage fits for their livestock operation. Grazing alfalfa should be considered a useful component in pasture systems and not simply a residue management practice in hayfields or a rescue harvest when haymaking is impractical. Order or download a pdf of this and  other National Alfalfa and Forage Alliance publications here.

Successful KFGC Field Day in Lincoln County

Over 170 people attended the KFGC field day held August 17 at Bill Holtzclaw’s farm in Lincoln County. Much of the success of the field day was due to the hard work of the county agent, Tyler Miller. A special thanks to Bill, his wife Linda and son Chris, employee Jim, and others who worked so hard to host this huge crowd. The field day highlighted important topics for producers in the area including: Grazing Summer Annuals by Dr. Chris Teutsch; Alfalfa Weed Control by Dr. J.D. Green;  Establishing Alfalfa by Dr. Ray Smith; and Making High Quality Baleage by Dr. Jimmy Henning. The drone photo shows the large attendance at the field day and the impressive hay and pasture fields at the Holtzclaw’s. Note the corn crop at the top of the photo. Bill and his father before him have been grazing standing corn in the late fall for the past 50 years. This has provided a high yielding/high energy feed for late season grazing. After grazing, Bill frost seeds red clover, alfalfa, tall fescue and orchardgrass into the trampled residue in February for 3 years of high quality pasture before planting the field back into corn. Dr. David Ditsch wrote a publication on Grazing Corn several years ago. Download from the Forage Website at: http://www2.ca.uky.edu/agcomm/pubs/id/id152/id152.pdf

Forage Timely Tips: September

  • If not already done, soil sample and apply fertilizer as needed.
  • Plant perennial grasses and legumes. Consider using a novel endophyte tall fescue.
  • Harvest hay as needed. Do NOT harvest alfalfa after mid-September.
  • Scout pastures, identify perennial weeds and woody brush. Consult an agricultural professional to determine the control strategy.
  • Closely monitor livestock and do NOT overgraze. Pasture plants accumulate energy reserves in the fall that help them overwinter and regrow in the spring.
  • Feed hay to allow pastures to stockpile for winter grazing.
  • Rest native warm-season grass fields until after frost for better winter survival.

Reasons to stockpile tall fescue this year

There are a lot of pressures on profitability right now. I have been doing a deep dive into hay production this year, trying to get a handle on the complexity, the science and the art of making good hay. What does this have to do with stockpiling tall fescue? Hay supplies and fall grazing are dynamically linked – the more grazing we can do in the late fall and early winter, the longer our hay supplies will last. And with the fires and drought in the west as well as untimely rains here, it may be a tight year for some types of hay. Here are several reasons why this might be the year for stockpiling of tall fescue.

Extend your grazing season and save hay by considering stockpiling tall fescue this fall. Having a rested tall fescue pasture (not overgrazed), the ability to make timely applications of nitrogen and the capability to strip graze are all good reasons this may be the year to stockpile. (Photo by Chris Teutsch, University of Kentucky.)

Longer grazing season. Stockpiling is producing forage now for use later. Using fall stockpiled forages is a great way to extend the grazing season into early winter and reduce the reliance on hay or supplements. Nitrogen fertilizer applied in August/early September will produce more yield per pound of nitrogen than later September or October applications.

Tall fescue is the ideal grass for stockpiling. Stockpiling is growing forage now for use later. Tall fescue is the ideal grass for fall stockpiling because it retains its quality and digestibility into late fall and early winter better than other grasses and legumes. Freezes and rain quickly degrade the quality of legumes and other cool season grasses. Tall fescue on the other hand will maintain leaf integrity through freezes and weather and therefore the forage quality will remain high.

Good stockpiled tall fescue is excellent forage for fall weaned calves as well as for the fall calving cow herd. Quality values for fall tall fescue can approach 20 percent crude protein and mid-60’s in total digestible nutrients. These values are far superior to most fescue hay. Protein content and digestibility decline at a slower rate over the winter compared to other forages.

Fescue toxicity from the endophyte tends to be low in fall stockpiled tall fescue. Although fescue toxicity can peak in the early fall, freezes will generally cause the toxic alkaloid levels to fall to near zero. Endophyte-free and novel endophyte tall fescues stockpile equally well as KY 31 and will not have toxicity potential at all. Use moderate levels of nitrogen fertilizer (use 60 or less pounds of actual nitrogen per acre, equivalent to 130 pounds of urea that is 46% nitrogen) to avoid the overproduction of the endophyte toxic alkaloids in the fall.

Pastures are in good shape to respond well to nitrogen. . Many areas have received enough rainfall to have excess pasture acres that will be perfect for stockpiling. Pastures that have not been overgrazed will respond most to fall nitrogen fertilizer. For best results, stockpiling should begin by mid-August. If excessive growth is present, mow or graze the fescue down to four to six inches to allow for new growth. Remove grazing livestock and find a good opportunity to apply nitrogen. Fall applied nitrogen is most efficient in producing additional yield when applied in late summer/early fall, as early as mid-August.

Avoid nitrogen loses by timing or adding urease inhibitors. Urea-based products are the most common sources of nitrogen for fall stockpiling. Urea applied to dry soil during hot conditions is subject to nitrogen loss due to urease activity in the soil. Urease is an enzyme that breaks urea down before it can be used by the plant. Urease is widespread in the environment. We can avoid this nitrogen loss by application in advance of a coming rain event or using urea that’s been treated with a urease inhibitor. Consult soil test values to determine if lime, P or K is needed. It is important to take current prices and individual situations into consideration when deciding if this practice will be cost-effective.

Strip allocation of stockpiled tall fescue will extend the grazing period. Missouri research showed that giving cattle a three-day vs seven-day supply of stockpiled tall fescue increased grazing days by 45% due to less trampling and less manure on fresh forage.  Stockpiled fescue can be grazed close with little effect on spring regrowth so utilization efficiency is high. In fact, tightly grazed stockpiled tall fescue pastures can be a good place to frost-seed clover in late winter. For more information on stockpiling tall fescue, see ‘Stockpiling for fall and winter pasture’ (http://www2.ca.uky.edu/agcomm/pubs/agr/agr162/agr162.pdf)

~Jimmy Henning, Farmers Pride

UK Equine Farm and Facilities Expo to be held Sept. 28

University of Kentucky Cooperative Extension Service and Ag Equine Programs will host its annual Farm and Facilities Expo from 3:30 – 8 p.m. EDT Tuesday, Sept. 28, at famed Spendthrift Farm, 247 Swigert Ave., Lexington. The event is free and open to the public. A meal will be provided for those in attendance.

Farm managers and horse owners alike will have the opportunity to explore visitor booths and see displays for every aspect of horse farm management. Speakers will provide educational talks about farm layout and planning, establishing new pasture and spray options for farms of all sizes. Additionally, Spendthrift Farm personnel will provide a welcome talk about engaging non-horsemen in the racing industry.

“We have held this annual field day for the last 12 years and this year’s event promises to be one of the best ever. Not only will you be able to tour a premier horse farm, but you will see the results of excellent pasture management. A priority for the field day will be to show each participant how they can implement the practices at Spendthrift on their own operation, whether large or small,” said Ray Smith, forage extension specialist with UK’s College of Agriculture, Food and Environment.

“In 2019, Spendthrift made the decision to completely re-establish some areas in cool season pasture. This is the best way to have a good pasture, and despite some heavy drought, this farm had great success with it.” said Krista Lea, research analyst and coordinator of the UK Horse Pasture Evaluation Program.

Please RSVP for food planning purposes. Please email equine@uky.edu to register. All current COVID protocols will be followed. ~ Holly Weimers

Watch Pastures for True Armyworm

Figure 1. True armyworm with typical leaf margin injury to seedling corn. (Photo: Ric Bessin, UK)

There has been one report of true armyworm damage in pastures, and moth numbers increased dramatically the week before last in Lexington. True armyworm and fall armyworm are two separate insect pests. The true armyworm overwinters in Kentucky and can be a serious early season pest of pastures, small grains, and corn. Cool, wet weather can favor armyworm development, and we have had some of that this year. Armyworm larvae are highly active at night and on cloudy days. With this late occurrence, producers should monitor pastures and late-planted corn for true armyworm activity.

While moth numbers are up, they are a small fraction of the numbers we experienced during the 2008 outbreak year. When larvae are a problem, they damage plants by eating leaf margins of upper leaves, defoliating entire plants, and clipping heads of maturing plants. In pastures, we would suggest treatment when armyworm numbers reach two to three per square foot. View the full article here. ~ Ric Bessin, from KY Pest News

KFGC Annual Field Day August 17

Lincoln county producer Bill Holtzclaw will be hosting the KFGC Annual Field day. 4610 HWY 590, Stanford KY. The program begins at 4:30 pm and includes Grazing Summer Annuals, Chris Teutsch, Alfalfa Weed Control, JD Green, Establishing Alfalfa, Ray Smith, and Making High Quality Baleage: Summary of Baleage Farm Sampling, Jimmy Henning. Register by calling 606-365-2447, this event will be a CAIP qualified educational meeting. Find more details here.

Forage Timely Tips: August

  • Do NOT graze cool-season pastures closer than 3 to 4 inches.  This will help conserve soil moisture and prevent overheating of plant crowns.
  • If drought conditions limit pasture growth, close off pastures and feed hay in a sacrifice area.
  • Graze warm season annuals or perennials to allow cool season grasses to recover and to avoid endophyte-infected fescue.
  • After the first good rain in August, seed winter annuals (such as small grains, ryegrass, crimson clover, and brassicas) for late fall and early spring grazing.
  • Plant alfalfa after first good rain in August to allow sufficient size going into winter and reduce potential for sclerotinia damage.
  • Consider renovation of cool-season grass pastures that have thinned.