Slay is a premium herbicide for broadleaf weed control in legume forages planted in food plots. It has been available for six years and has been widely accepted with positive results across the United States. For new users, a refresher discussion on Slay will help set the foundation for equally positive results.
Slay controls a broad spectrum of broadleaf weeds in pure stands of clover or alfalfa. The chemical nature of Slay allows it to be applied at low rates, which is ideal for small-acreage plantings of food plots by hobbyists. Slay is unique among herbicides in that it controls emerged weeds and nonemerged weeds. Foliar uptake is fairly rapid and facilitated by spray adjuvants, such as a crop oil concentrate and non-ionic surfactant. Soil uptake is by plant roots. In both cases, the herbicide is translocated throughout the plant and accumulates at growing points, where symptoms first appear. In susceptible plants, Slay inhibits production of a specific enzyme in photosynthesis. A few hours after adsorption by susceptible plants, growth ceases — although that may not be immediately noticeable. Whole plant symptoms might take up to two weeks to develop.
In forage legumes, Slay is applied after clover has at least two trifoliate leaves (two to three inches tall). Applications at this stage of forage growth ensure adequate crop safety and minimize chances for significant crop stunting. Another consideration on when to apply Slay is weed size. Consider Slay to be a “weed-seedling herbicide.” Some weed species, such as cocklebur and wild radish, are very sensitive to Slay and acceptable control of larger plants can be achieved. However, most weed species are very unforgiving if Slay is applied too late. Refer to the Slay label for specific information on critical weed sizes and herbicide rates for consistent control.
ENVIRONMENTAL CONDITIONS THAT AFFECT SLAY PERFORMANCE
Slay performance can be directly affected by weather conditions before, during and after application. One factor to consider is temperature. Since temperature affects the rate of photosynthesis in plants and Slay inhibits a specific enzyme in photosynthesis, extreme temperatures will reduce weed control with Slay. Plants (crops and weeds) that tolerate Slay rapidly detoxify the herbicide. Cooler temperatures slow detoxification in tolerant plants. Research has shown that tolerant legume crops treated with Slay are stunted when cool temperatures (less than 40 degrees F) prevail and slower to recover compared to plants treated under moderate temperature regimes. This is also true for susceptible weeds responding to Slay. Cool temperatures slow photosynthesis and symptoms take longer to develop.
Slay performs well during periods of high humidity. Slay directly affects photosynthesis and conditions that promote photosynthesis help maximize performance, which is the case with high humidity. Humid conditions also thin the cuticle on leaf surfaces making it easier for herbicides to enter the plant. In addition, humid conditions increase water transpiration and movement in plants, with Slay being moved throughout the plant with the water in the plant vascular system. It is worth mentioning the unfortunate results if humidity is low and prevailing conditions are arid. Weed control with Slay will be significantly reduced due to the opposite reasons.
RESIDUAL WEED CONTROL
A significant, yet under-appreciated, attribute of Slay is residual control of non-emerged weeds. Herbicides in the same chemical family as Slay are frequently soil-applied at planting to other legume crops such as soybean, peanut and edible legumes. We do not have that option with Slay on forage legumes since chances of significant stunting are greater on newly emerged clover. Residual weed control with Slay can be captured to our benefit if applied early in the life of the forage planting. At that time, forage legumes are developed enough to tolerate Slay, but the plants are vsmall enough to not cover the soil surface. Simply, if Slay spray droplets can reach the soil surface, the stage is set for control of non-emerged weeds.
Another opportunity to use soil residual weed control with Slay is soon after rejuvenating a clover stand with mowing. Rotary mowing is a tried and proven practice to freshen a clover food plot; usually to stimulate new growth, facilitate efficient topdressing with fertilizer, and clip tall weeds. Mowing opens the clover leaf canopy, allowing spray droplets to reach the soil surface and creating an opportunity for Slay to provide residual weed control. Ideally, mow the clover food plot and wait about two weeks before applying Slay. Not only will the clover leaf canopy be open, giving herbicide spray an opportunity to reach the soil surface, the delay will allow established weeds to re-foliate with young succulent leaves that are primed for herbicide uptake.
Admittedly, the benefits of residual weed control with Slay are tricky to capture in forages. However, the potential weed control benefits are significant. Slay is the sole herbicide available for use in forage legumes that is equally active between soil applications and foliar applications. Opportunities to use these attributes are too valuable to overlook.
SENSITIVITY OF OTHER FORAGE SPECIES TO SLAY
While forage legumes are generally very tolerant of Slay, other non-legume forages tend to be sensitive. For example, all brassica forages are very sensitive to Slay, along with grain sorghum (milo), cereal grains, and sunflower. Most forages planted for food plots are multi-species blends. While forage legumes may be the foundation species in the blend, other plants in the mix may be sensitive to Slay. This pretty much eliminates the opportunity to use Slay for weed control in these plantings. More importantly, the significant soil activity of Slay might temporarily limit future plantings of multi-species blends. Refer to Table 1 for a list of planting restrictions following applications of Slay. This is not meant to discourage using Slay. Rather it is the nature of this general family of herbicides and Slay is certainly no different.
Sensitivity of non-legume forages to Slay can actually be a useful tool. For example, cereal grains such as oats are often seeded with Imperial Whitetail Clover as a companion crop to entice deer and protect clover from over-grazing early in the life of the food plot. However, at some point oats transform from a companion crop with the clover to a weed that robs clover of light, nutrients and water. In this example, Slay can be used to selectively remove (control) oats along with other weeds once the clover becomes established. Similar uses exist with most multi-species forage blends if a legume is the foundation species.
Slay is a thoroughbred herbicide and a valuable tool in the integrated management of weeds in food plots planted to clover or alfalfa. While the herbicide might be temperamental in regard to environmental conditions necessary for optimum performance, Slay delivers outstanding weed control. This valuable tool will greatly improve the longevity and vigor of clover and alfalfa food plots by eliminating broadleaf weeds and their competition. As with any herbicide, be sure to read the directions thoroughly for replanting guidelines before any herbicide is applied to your plots.
