Later in the season — July and August — most peanut growers get grass escapes in peanuts. It makes sense to add grass herbicides with fungicides, because growers are typically applying fungicides every two weeks or so.

Jordan says chlorthalonil products or Headline or Abound tend to reduce grass control enough to get your attention.

“By contrast, we have not seen the same loss in grass herbicide efficacy when these materials are mixed with tebuconazole products and Provost,” Jordan says.

“Although it’s not on any label that I’m aware of, increasing the grass herbicide rate by 20-25 percent most likely will overcome the loss of grass activity in a tank-mix with fungicides,” Jordan points out.

“In general, we haven’t seen any major problems with disease control when fungicides are tank-mixed with herbicides or other pesticides. As long as these materials don’t settle out and cause problems in the spray tank, we just haven’t seen many problems,” Jordan says.

Likewise, there have been few problems with insecticide efficacy. Plant growth regulators, like Apogee, also have not had any significant problem with tank-mixing.

“And, some peanut growers are tank-mixing micronutrients, like boron and manganese, and only now and then do we see a minor drop in weed control, when these materials are tank-mixed with broadleaf herbicides,” Jordan says. 

“We are sometimes concerned that applying boron with a herbicide and the appropriate adjuvant will produce more absorption and the possibility of foliar burn on peanuts. 

“This does not seem to be a concern with manganese, but some foliar burn with excessive boron is not uncommon. The adjuvant often is the culprit in this case,” Jordan says.

There are thousands of options for tank-mixing and generally different pesticides are compatible with other materials with respect to foliar applications.

“There are also questions about mixing insecticides, fungicides and inoculant in the seed furrow. We do need to use caution here, Jordan stresses.   

“With the price of seed, growers should be certain they will not do things like applying products in the furrow that have not been evaluated. There is too much at stake given the cost of peanut seed,” he adds.

(It has been said that it's all in the timing when talking about peanut disease and nematode control. And that would be especially true this year when acreage is expeced to increase by 25 percent. A University of Georgia specialist recently sat down to discuss that timing. To see his comments, visit