Late Season Glyphosate Applications

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Question from Mitch:

Have you heard of using glyphosate as a harvest aid in peanuts? Specifically, it is to improve pod fill on tap root nuts as they wait for younger ones to develop.??????? One grower has inquired.

Yes, there was a product many years ago called Quota Maker (spelling?) that was marketed for just a short time. This type of approach should not be done for two reasons. First one is that it is illegal and glyphosate is not labeled for use in peanut. Second, that type of application was inconsistent in part because it is hard to know just when to make the application because flowering is difficult to predict (amount and duration.) For example, if you could consistently spray at say 80% completion of flowering and eliminate the last 20% you might have something. The challenge is people would spray at 65% flowering and losing 35% of flowers is too many and will cause a yield hit. And, environmental conditions certainly can impact how many flowers are lost with an application. Very unpredictable. A parallel is the first generation of Roundup Ready cotton and fruit shed with late applications of glyphosate. Sometimes there was a big yield hit and sometimes not so much. But predicting either way was a challenge. There are some growers that add a couple of ounces every time they spray fungicides (at least years ago there were rumors that this was going on.) This was done to curtail vegetative growth. That too was an illegal application and a risky one from a biological standpoint. But the short answer is that it is illegal and puts the crop in jeopardy for marketing.

Article first appeared as North Carolina Peanut Note (PNNC-2013-065)