A major obstacle in cotton (Gossypium hirsutum L.) production is obtaining a stand of vigorous see rings that are uniformly spaced along the row. Although all planting seeds are coated with fungicides, more effective treatments are needed. The experimental fungicides APRON, EPIC, and CGA 64251 control primarily Pythium, Rhizoctonia and Thielavioposis, respectively, the major seedling disease pathogens. These fungicides were evaluated singly and in all combinations to determine their effects on plant stands (percent surviving seedlings) and lint yield of cotton. The fungicides were applied to sub-lots of acid-delinted Stoneville 213 seed. Samples of seed from the same treated batch were evaluated at Tallassee, AL, Stoneville, MS, Lubbock, TX, and Shafter and Davis, CA. Significant differences in stands occurred among the treatments in all tests, except the one at Lubbock. Then only one fungicide was applied to the seed, the overall average percentage of surviving seedlings was higher for seed treated with APRON (48%) than with EPIC (37%) or CGA 64251 (38%) indicating that Pythium was the major pathogen reducing stands. Mississippi stands were significantly higher for seeds treated with APRON + EPIC, CGA 64251, or EPIC + CGA 64251 than with APRON alone, indicating that Rhizoctonia and Thielavioposis reduced stands also. Additive effects from combinations of fungicides were not observed at the other locations.

Lint yields were measured only from the test conducted in Mississippi. Lint yields differed significantly among the treatments, even though those of the fungicide treatments were not different from the control. Lint yield increases over the control (1189 kg/ha) ranged from 1% for APRON to 127, for EPIC with 9 to 11% increases for combinations of fungicide. However, yield was 13% lower for CCA 64251 than for the control. Covariance analysis indicated that lint yields were not affected significantly by plant populations.