Today I welcome the Fayette Co. Extension Director, Jeff Via as a guest blogger.  Jeff works with rowcrop farmers and livestock producers.  He has recently been working on perennial foxtail in pastures. 

Perennial Foxtail Confirmed in Hayfields  -Jeff Via

For some time, Extension Agents have preached that properly managed pastures and hayfields can provide much of the feed needed for livestock (horses and cattle). We taught that when well-managed, theses forages can provide an inexpensive, high quality feed. Poorly managed pastures and hayfields on the other hand, are unattractive and could potentially be the cause of some health/nutritional problems.

While controlling grasses in a grass hayfield has been an issue for many, it wasn’t until a couple of years ago, a few agents started receiving calls on hard to control foxtails. At this time a fairly new product had surfaced called Pastora (Nicosulfuron+metsulfuron). Pastora is a premix of the active ingredients in Accent and Escort herbicides.

Using rates of 1 oz./acre gave good control when applied overtop to control johnsongrass, broadleaf signalgrass, barnyardgrass, fall panicum, foxtails and many broadleaf weeds.

Now, producers in many cases, were doing what we at UT recommended but these well-managed hayfields were looking poorly managed. This had producers, Extension Agents and chemical representatives scratching their heads, making many trips to producer’s fields and causing apprehension about using some of the products we recommended.

Foxtail was one of the biggest concerns for hay producers and buyers due to the ulcers that some horses got if they consumed hay containing it (look at picture).

 

In many fields, Pastora and Pastora/Glyphosate gave limited control of foxtail. It was not until about a month ago that knotroot foxtail, Setaria parviflora a perennial foxtail was found in abundance in hayfields in Fayette and Shelby counties. Easy to identify, this perennial has fibrous roots with short, knotty rhizomes (look at picture). 

Many producers have applied a dormant spray of paraquat or glyphosate or a combination of one of those with pendimethalin at varying rates. The fields that had the higher rates showed better suppression of the seedling perennial and annual foxtail to date. Other fields had both perennial and seedling foxtail coming up after a glyphosate/pendimethalin treatment. Not sure the reason why the seedlings came up but probably due to too much rain. Rain is needed to activate the pendimethalin. One thing to note, the pendimethlin will do nothing to the perennial foxtail already in the field.

To date, the perennial foxtail is 8-10 inches in height in many fields with seedlings coming up as well. In a normal year, our recommendation would be to apply a dormant spray then apply Pastora at 1.5 oz./acre with 8 oz./acre Glyphosate 4 lb. product with a non-ionic surfactant at 1 qt./100 gal. 3-5 days after cutting. This would then be followed by 1 oz./acre Pastora 10-14 days later and depending on the problem, add more glyphosate.

With the warmer than normal temperatures, our recommendation today is the same as above but earlier. We are recommending folks apply Pastora at 1.5 oz./acre with 8 oz./acre Glyphosate 4 lb. product with a non-ionic surfactant at 1 qt./100 gal. when the foxtail is about one foot tall, which in some places will be about one week. Follow this with 1 oz./acre Pastora 10-14 days later and depending on the problem, add more glyphosate. Remember according to the Pastora label we cannot apply more than 2.5 oz./acre per season.