The Tropical Storm Colin came from the Gulf of Mexico and traveled the most important peanut production areas of the state. We had between 3 and 7 inches reported around the county. The subsequent rain will have impact on diseases affecting peanuts (and other crops). This also coincides with the time when growers are beginning their fungicide program. Also, it is the time when the peanut plant is shifting from vegetative growth to reproductive growth (flowering).
UGA Extension Plant Pathologist Dr. Bob Kemerait has this information:
Within a month after planting, the peanut crop enters the window where a traditional disease management program begins. An important principle of disease management on any crop is to apply fungicides prior to disease onset.
The most important disease observed in 2016 has been Aspergillus crown rot, a fungal disease that is our most common seedling disease. It is often diagnosed by the abundant black/sooty sporulation on the crown of the plant, typically just below the soil surface. The disease is most common in very hot and dry soils where the tender taproot and shoot is scorched by the surrounding soil, thus creating injury that is exploited by the fungus. The disease is also found where lesser corn stalk borers are a problem. Fungicide seed treatments are effective in managing this disease but can suffer when conditions favor crown rot. In-furrow applications can also reduce outbreaks of Aspergillus crown rot. Foliar fungicide applications after disease is observed have not been especially helpful.
Tomato spotted wilt is showing up more and more on young peanuts. It was my observation that feeding injury from thrips was severe on both cotton and peanuts this year; I am concerned that we may see more TSWV this year than we have in the recent past. While there is nothing to be done at this point, being able to diagnose the problem and to explain why the disease has occurred in a field is helpful.
White mold: I have not seen white mold on peanuts thus far in 2016, but strong early-season growth of the peanut plants coupled with very warm soil temperatures can set the stage (as in 2015) for a “white mold year”. The 2016 year may also be problematic for white mold because A) many growers are on shorter rotations and B) because of the price of peanuts, growers may be reluctant to spend more money on “premium” products.
Growers can begin a white mold fungicide program earlier than the traditional “60 days after planting” in a number of different ways. Two popular ways include banding a white mold fungicide like Proline early in the season and also by mixing a fungicide like tebuconazole with early leaf spot fungicide applications.