Paraquat and Thrips Damage
If you see the relatively minor injury noted below from thrips (Image 1), the cumulative impact of thrips injury and paraquat injury will be minimal. In most cases these stresses alone and in combination will not reduce yield. If you apply paraquat to peanuts with severe injury (Image 2) a yield reduction most likely will occur. This level of peanut injury will almost always cause a yield reduction even without the added injury from paraquat. The combination of yield loss will exceed that of the individual stresses. But most fields do not have this much injury unless insecticide was not applied to seed or in-furrow. And hopefully, most people sprayed insecticide soon enough to keep this level of injury from occurring. These peanuts were planted May 2 and Orthene would have been targeted about 2 weeks ago for peanuts at that time. However, without insecticide applied at planting (Image 2), Orthene should have gone out earlier, within 2 weeks after peanut emerged. Rick has a lot of data showing these concepts if you would like more detail. If for some reason the thrips “got away from you” and there is significant injury (Image 2), it is best to get Orthene or some other effective insecticide out ASAP and then worry about the weeds after the peanuts have recovered (the following week or so). The final image (Image 3) is of peanuts planted May 19 without insecticide. These need a shot of insecticide ASAP (thrips are present) and are approaching the point where the combination of thrips injury and paraquat injury will be compounded (perhaps sometime late next week those peanuts may look like image 2 depending on thrips populations). Orthene can be applied with paraquat and Basagran in this case, right now, but perhaps not a week from now if the injury from thrips continues to progress.
Check out my mom’s bass caught while fishing for brim and perch using a cane pole.
Article first appeared as North Carolina Peanut Note (PNNC-2014-067)