The following is the column I provide for the Peanut Grower Magazine. This is posted early because it needs to be prepared about three weeks in advance and I might forget to post it in June.
In the Virginia-Carolina region, I often consider June as a transition month, especially as we move to the last week of the month. We have dealt with weeds and thrips as high priorities in May. I hope that our residual herbicides at planting and likely paraquat and Basagran applied with additional residual herbicides have been effective. Weed scientists often refer to the “critical period of weed control” as first three to six weeks of the season. If we can keep the crop clean during that period, we have likely protected it well enough to optimize yield. Preventing early season weed interference is where we get the most out of our herbicide programs. However, peanuts are unique compared to some of our other crops. Because they never get very tall, it does not take much for a weed to get above the canopy. That fact, along with the need to dig and invert vines and because we make numerous fungicide applications, requires us to keep fields weed-free for the balance of the season. Our window for paraquat often ends in June (spraying within 4 weeks after peanut emergence) and we will shift to PPO inhibitors (Storm, Ultra Blazer, Cobra, 2,4-DB, selective grass herbicides, or Cadre/Impose.)
Our insect control needs also shift from suppressing thrips to addressing rootworms, spider mites, and foliar-feeding insects. We have good options for spider mites (if we are timely) and foliar-feeding insects (pyrethroids are about 60% effecting on corn earworms while the more expensive products are almost completely effective and do not flare mites, in most cases.) We do not have a chemical option for rootworms. There is a void in the absence of chlorpyrifos (Lorsban.) In our research, we have not seen value in multiple postemergence sprays of insecticides to control the adults. Some of these products are expensive when you consider three sprays.
We encourage growers to apply gypsum later in the month, although I suspect by the time this column comes out a lot of gypsum will have already been applied. My concern on the early applications is the big rain events we can get in early to mid-June when peanut plants are small. I just hate to see soil and gypsum wash down to the middles.
Planning for leaf spot and stem rot sprays is high on the list in June. Further south, many growers begin their fungicide sprays 30 days after planting. In the mid and upper V-C region, we recommend starting at about 45 days after planting but no later than July 10. Generally, temperatures are higher further south, peanuts have likely come up more quickly after planting, and inoculum for leaf spot can be higher. This is why we can often get by with a five-spray program in North Carolina and Virginia compared with more sprays in Alabama, Florida, Georgia, and South Carolina. We also refer to the R3 stage of growth as the starting point in North Carolina. This would be the case unless peanuts were planted late, and if that instance we need to initiate sprays no later than July 10. As we move into July, do not forget to include manganese and boron. In most cases, these products can be applied with herbicides, fungicides, and insecticides.
Prohexadione calcium (Apogee or Kudos) will come later, well into July. Lots to do in June and early July.