|GARCIA, JORGE - California State University|
|HUTMACHER, R - University Of California, Davis|
|ELLIS, M - California State University|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/8/2022
Publication Date: 8/10/2022
Citation: Garcia, J., Hutmacher, R., Ulloa, M., Ellis, M. 2022. Effects of Fusarium oxysporum f. sp. vasinfectum and Rhizoctonia solani on disease development in Pima and Upland cotton. Plant Health 2022. Pittsburg, Pennsylvania, August 6-10, 2022. ID: 22129.
Technical Abstract: Two important soilborne pathogens of cotton include Fusarium oxysporum f. sp. vasinfectum (FOV) and Rhizoctonia solani. A previous interaction study found that when Pima cotton was inoculated simultaneously with both pathogens more disease development occurred than with a single pathogen. The objective of this study was to further evaluated the interaction of both pathogens with FOV susceptible and moderately tolerant Pima and Upland cotton varieties. Additionally, an improved inoculation assay was developed to study this interaction where seeds were planted into pots with a layer of infested-oat seed inoculum with the following treatments: FOV alone, R. solani alone, co-inoculation with both pathogens, and non-inoculated oats were used as a control. At five weeks, stand counts, shoot and root weight, foliar, vascular, and root rot data were collected. There was significantly more disease development in the co-inoculation and R. solani treatments for stand counts, shoot weight, and root rot data (P<0.05). FOV foliar and vascular symptoms increased in the co-inoculation treatment when compared to the FOV treatment (P<0.05). These symptoms were also most severe in the FOV susceptible Pima DP 340 when compared to FOV moderately resistant Pima DP 359 and the more tolerant Upland cotton varieties FM1830 and PHY 72. However, disease development increased in the more tolerant cultivars when co-inoculated with both pathogens. Therefore, the results from this study provide further evidence that R. solani may compromise FOV tolerance in Pima and Upland cotton plants.