They found that early morning before sunrise was the best time to spray. The dew on curled leaves helps the fungicide slide further down the plant.

Last year, Georgia farmers averaged 3,400 pounds of peanuts per acre. In research plots, switching to nighttime spraying typically improved yields by 200 pounds to 800 pounds per acre. In plots where white mold was a severe problem, nighttime spraying increased yields by 1,800 pounds per acre. In research plots where white mold was not a problem, switching spray times made little improvement.

“It was fascinating to me to see the level of improved control without there being any additional cost. That’s unusual,” said Brenneman, a plant pathologist for 25 years.

Most tractors have lights for night work. Satellites can now guide many tractors. Spraying at night, he said, wouldn’t cost farmers more money. The same product would be sprayed at the same rate, just at night. The only cost might be an occasional shift in sleeping habits.

All farmers shouldn’t rush to set the alarm earlier or pull an all-nighter to spray, he said. But the information will be useful for some.

A farmer who has had trouble controlling soil-borne disease with fungicides or is looking to reduce costs by using less- expensive chemical this year would see benefit, he said.

Georgia farmers recently finished plantings what is expected to be 500,000 acres of peanuts this year.

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