Control of Cotton Seedling Damping-off by Treating Seed with Inorganic Salts

The efficacy of forty treatments of inorganic salts as possible alternatives to synthetic fungicides for suppressing damping-off of cotton seedlings was evaluated. Seed treatments at rates of 2, 4, 6, 8, and 10 g salt per kg seeds were applied. The results showed that potassium phosphate monobasic (2 g per kg seeds) was the least effective salt in controlling the disease, while ammonium phosphate dibasic (4 g per kg seeds) was the most effective one. The linear growth of Sclerotium rolfsii and Pythium sp. was wholly inhibited at concentrations as high as 40 and 50 mM, respectively. On the other hand, potassium bicarbonate was not able to completely inhibit the linear growth of any of the other fungi even at the highest concentrations. The tested fungi showed differential sensitivities to the applied concentrations of potassium bicarbonate, as their differential regression models demonstrated. The interaction between three randomly selected treatments of inorganic salts and seven fungi involved in the damping-off of cotton seedlings was evaluated under greenhouse conditions. ANOVA showed an insignificant interaction between treatments and fungi. These comparisons showed that all treatments were effective in controlling the disease. In conclusion, bicarbonate as anion and potassium and ammonium as cations were effective in reducing damping-off. Also, acidic treatments were more effective than alkaline ones in controlling the disease. It can be concluded that inorganic salts may have potential as environmentally compatible nontoxic seed-dressing fungicides for controlling damping-off of cotton seedlings.