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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Soil Management and Sugarbeet Research » Research » Publications at this Location » Publication #307036
Title: Evaluation of Rhizoctonia zeae as a potential biological control option for fungal root diseases of sugar beet

Author
item Webb, Kimberly
item HARVESON, ROBERT - University Of Nebraska
item West, Mark

Submitted to: Annals of Applied Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2015
Publication Date: 6/2/2015
Publication URL: http://onlinelibrary.wiley.com/doi/10.1111/aab.12210/abstract
Citation: Webb, K.M., Harveson, R.M., West, M.S. 2015. Evaluation of Rhizoctonia zeae as a potential biological control option for fungal root diseases of sugar beet. Annals of Applied Biology. 167: 75-89. doi: 10.111/aab.12210.

Interpretive Summary: Root diseases often impact sugar beet through most production areas of the Central High Plains. Due to the lack of available chemicals for disease management, alternative techniques such as biological control using mycoparasitic fungi are being investigated. At least two promising mycoparasites have been identified from soil assays that inhibit numerous sugar beet root pathogens, including Rhizoctonia solani, Fusarium oxysporum f. sp. betae, Phoma betae, and Pythium aphanidermatum both of which have been identified as Waitea circinata. Pathogenicity testing against sugar beet as a host indicated that these isolates were not pathogens of sugarbeet and were shown to provide some level of protection for the entire season against a complex of sugar beet diseases. This data suggests that these isolates could have a potential as biocontrol management for several sugar beet root diseases.

Technical Abstract: Several common root diseases routinely damage sugar beet in Nebraska and other production areas of the Central High Plains, and it is becoming more common to find fields infested simultaneously with multiple pathogens. Due to the lack of available chemicals for economic management of soilborne diseases, alternative techniques such as biological control are increasingly being sought for disease management. Over the last several years, unidentified, sterile fungi have been isolated in conjunction with infected sugar beet roots and seedlings. At least two promising mycoparasites have been identified from in vitro assays that inhibit numerous sugar beet root pathogens, including Rhizoctonia solani, Fusarium oxysporum f. sp. betae, Phoma betae, and Pythium aphanidermatum. Based on morphological and molecular characterization, two isolates, ‘Hall’ and ‘R47’ were identified as Waitea circinata. Pathogenicity testing against sugar beet as a host indicated that these isolates were not pathogens. Both isolates were compared with the well-established biological control fungus Laetisaria arvalis and tested as potential seed treatments in a field naturally infested with multiple sugar beet root diseases. Data indicated that these fungi provided some level of protection for the entire season against a complex of soilborne diseases and suggests that these isolates could have a potential fit in an integrative management strategy for several sugar beet root diseases.