Most fungi require water to infect and develop.
Although drought factors tend to reduce disease incidence there are some disease situations that are enhanced. 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. The damage is many times not realized immediately but may take four to six months before symptoms occur.