Seasonal fluctuations in cotton seedling pathogens in three west Tennessee soils

The total number of Pythium Isolates found had a significant seasonal variation in incidence. P. ultimum also showed significant seasonal variation. The genus Fusarium was found to have a highly significant seasonal variation. Only one pathogen, a mycelial form of Pythium not producing sexual spores, had a significant variation with regard to soil type. Of all discolored hypocotyls there was a significantly greater incidence in soils not cropped to cotton than in soils cropped to cotton. Thielaviopsis showed a reversal of this trend and had a significantly greater incidence in soils cropped to cotton than in soils not cropped to cotton.