Plant disease-causing fungi are usually inhibited during periods of drought. Most fungi require water to infect and develop. Although drought factors tend to reduce the risk of disease, there are some disease situations that are enhanced.Leaf spotting fungi in the Helminthosporium complex are more severe when the potassium levels are low. The lack of soil moisture due to droughts can affect the availability of these nutrients although there may be adequate levels in the soil. During dew periods and other sporadic moisture periods, nutrient deficient plants can become infected and disease can develop. These leaf-spotting disease fungi can reduce hay quality.