2).Īs the disease progresses other signs appear on the limbs and soil surface as white sclerotia that turn tan then brown as they mature. The southern blight fungus is usually first observed in July in peanut as white hyphae followed by wilted or blighted (rapid death of leaves) leaves (also called flagging) (Fig. Typically, this disease imposter is the first white fungus observed in June in peanut fields. It is characterized as having “tooth like” projections and as it matures the fungus turn from white to yellow in color. Phanerochaeteis a wood rotting fungus that poses no threat to peanut. 1), so look close to make sure its southern blight fungus, Sclerotium rolfsii. With that said, a word of caution, Phanerochaete is a southern blight fungus doppelganger (Fig. Southern blight can be identified in the field by signs (seeing the fungus) and symptoms (plant response to disease) of the disease. Scout fields with a history of the disease for white hyphae on the soil surface near the peanut limbs. See MP154 for fungicides used to control southern blight in Arkansas. Relying on a calendar program alone could open a window at the start of the season for late leaf spot in September, see last paragraph. Some apply fungicide at night when peanut leaves are closed when overhead irrigation is not an option.
Though fungicide treatments often begins in July to control southern blight, scout fields for crop maturity and disease signs and symptoms to confirm the need for starting a fungicide program.Īpplying fungicides to control southern blight before a rain or overhead irrigation is a good idea to get the product near the soil surface. In fields where the canopy has yet to meet the threat of southern blight is lower than where the limbs have met across the furrow. In fields where the canopy has met a micro climate is created near the soil surface that promotes fungal development.
mat growing on soil surface near a peanut plant. If sclerotia of either pathogen make their way back into the soil, both can survive for years causing significant problems.Īll infected plants need to be removed immediately and disposed of properly to help reduce the chances of sclerotia returning to the soil.įor more information on chemical control please see the 2022/2023 mid-Atlantic Commercial Vegetable Production Recommendations Guide.Figure 1. The pathogen produces large black sclerotia on the surface and inside infected stems. White mold is more common than Southern blight in New Jersey, and like Southern blight, once introduced into a field or high tunnel it can very difficult to control. The fungus will produce white, cottony mycelium and very small, spherical sclerotia which are often have a tannish, brown color. The resulting infection will girdle the plant causing wilt and death. Symptoms of Southern blight include infection at the base of the stem at the soil line. Like white mold, it can survive in the soil for many years. Southern blight is much more common in vegetable areas south of the state where summer temperatures remain hotter (above 90☏) for longer periods of time.
There have been a few reports of Southern blight ( Sclerotinia rolfsii) and White mold ( Sclerotinia sclerotiorum) on tomato and pepper in New Jersey.
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