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Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/27/2006 Publication Date: 8/10/2006 Citation: Howell, C.R. 2006. Effect of seed quality and fungicide/Trichoderma spp. seed treatments on pre- and post-emergence damping-off in cotton. Phytopathology. 97:66-71. Interpretive Summary: Seedlings grown from good quality cotton seeds often escape pre-emergence seedling disease, and they are more resistant to post-emergence disease. Poor quality cotton seeds are highly susceptible to both forms of seedling disease. However, the work reported here has shown that cotton seeds can be protected from both pre- and post-emergence seedling disease by treating the seeds with a combination seed treatment of a fungicide and a biological in the form of Chloroneb and a Trichoderma species. This work may ultimately help in assuring that planted cotton seed germinates properly to result in good stands which will contribute to increased production efficiency and profitability to U.S. farmers. Technical Abstract: Good quality seeds of cotton cultivars often escaped pre-emergence damping-off incited by Pythium spp. and Rhizopus oryzae, and they were resistant to post-emergence damping-off incited by Rhizoctonia solani. Poor quality seed, however, were highly susceptible to both phases of seedling disease and required seed treatment in order to survive. Pre-emergence damping-off incited by Pythium spp. and R. oryzae could be controlled by seed treatment with biocontrol preparations of a number of Trichoderma spp., but these treatments were much less effective in controlling post-emergence disease incited by R. solani. Post-emergence seedling disease can be controlled by fungicides, but they were much less effective in controlling the pre-emergence phase of the disease. Combination seed treatments of poor quality cotton seeds with fungicides and Trichoderma spp. preparations, followed by planting in pathogen-infested soil, indicated that this technique will control both phases of seedling disease. Seed treatment with either the fungicides or the biocontrol agents alone did not achieve this goal. The optimum combination treatment for disease control was that of Chloroneb + Trichoderma spp., followed by Deltacoat AD + T. virens strain G-6. |
