Just in case it was overlooked, Dr Anco included a table with the rain-free period for many of the fungicides we use. I’ve provided it here. Based on that table, if you get a few hours without rain after application, efficacy is likely not compromised by rain. If you are concerned about protection but have only a few hours without rain, rather than apply the next spray immediately, I would tighten the interval between the spray in question and your next spray. One question is about follow ups after Miravis plus Elatus. This program is protective only, so if you were rained out this week, make sure your next spray is not Chlorothalonil plus tebuconazole. This spray is a protectant only, and a fungicide treatment with a degree of curative activity is best.

Try not to panic if this week is 3 weeks since your Miravis plus Elatus spray. Historically, this program has given us 4 weeks of protection. However, spray your follow up just as soon as you can. Control and yield drop in a major way if the interval between Miravis plus Elatus and the next spray is 5 weeks.

With respect to prohexadione calcium, don’t repeat the spray immediately or even the following week if you were rained on after the spray. We just sprayed a trial yesterday that only had 45 minutes. However, it is likely that we will get a lot out of that spray. We do not need to apply high rates of Prohexadione calcium. If we spray very soon after a spray that is in question, and we get good activity out of the spray in question, the second spray will result in the plant getting a much higher rate than needed. We know we can apply too much Prohexadione calcium. There have been reduction in peanut yield in some cases.