May is one of our busiest months on the farm, especially when it comes to peanuts. The primary pests we are dealing with, other than the fact that we have fungicide-treated seed to protect us from soil-borne pathogens, is protection from thrips (and subsequently tomato spotted wilt) and weeds. In much of the V-C region, thrips control can involve a two-step process. The vast majority of farmers apply a systemic insecticide in the seed-furrow at planting followed by a foliar application of acephate. Regardless of what we use in the seed furrow at planting (e.g., AgLogic, Admire Pro or generic imidacloprid, Thimet or Phorate, or Vydate,) a foliar application of insecticide is needed. The duration of time needed for protection from thrips is often predicated on planting date, emergence date, and environmental conditions that promote or delay rapid growth of peanut. Each spring is different, but we often need two applications to adequately protect peanuts. Controlling weeds is also critical in May. Yield can be reduced by interference from weeds during the first month of the cropping cycle. Interference is the combination of competition for light and other resources by weeds and allelopathy from weeds that can affect peanut growth. For folks using reduced or conservation tillage (no till or strip till,) an effective burndown is essential. We need to start clean, and in reduced tillage systems herbicides are the key. It takes at least two sprays to get winter weeds and emerged summer weeds under control. Residual herbicides applied with non-selective foliar absorbed herbicides is essential in many fields. In North Carolina and Virginia, some growers run into dogfennel both before and after the crop is planted. Making sure dogfennel is suppressed in the fall and is killed as well as possible before the peanut crop emerges is extremely important. There are no herbicide options that are completely effective once peanuts emerges. For conventional tillage, making sure weeds are dead with tillage, especially in wet springs when weeds can get covered up with soil or re-root, is important. In those springs, applying herbicide before primary tillage begins can make a big difference. The last thing we want to do is start the cropping cycle with a significant number of 12-inch weeds present across the field.

Of course, we rely heavily on herbicides to suppress weeds and protect yields. Overlapping residuals early in the cropping cycle protects peanuts from weed interference and takes the pressure off postemergence herbicides. If I had it my way (which I do not in most cases,) pendimethalin would be incorporated uniformly across all peanut acres that are conventionally tilled. Then, a solid preemergence herbicide program would be applied just after peanuts are planted. This program would include flumioxazin (Valor SX and other formulations) mixed with a Group 15 herbicide. In some situations, Valor SX and a Group 15 herbicide can be mixed with Brake. I would consider paraquat (Gramoxone and other formulations) applied within 3 weeks after peanuts emerge along with Basagran and a Group 15 or other herbicide with residual activity against key weeds. In the southeast, folks would likely use Storm rather than Basagran. Then, based on what slips through and what you have experienced historically, a contact herbicide like Storm, Ultra Blazer, or Cobra, and in some cases Cadre/Impose would be in order. Based on your history with weeds, it might be good to include more residual.

So, I’ve spent a lot of your money at this point. My experience is that herbicides pay for themselves in the vast majority of fields. Being intensive with herbicides early in the season, and overlapping residual herbicides, brings the most to the table. We need to control weeds all season, but the early season control sets us up for greater success.