Location: Sugarbeet and Bean Research
Title: Rhizoctonia belly rot in cucumber fruit using Rhizoctonia solani isolated from sugar beet Authors
Submitted to: American Society of Sugar Beet Technologists
Publication Type: Abstract Only
Publication Acceptance Date: December 16, 2010
Publication Date: March 2, 2011
Citation: Goodwill, T.R., Hanson, L.E. 2011. Rhizoctonia belly rot in cucumber fruit using Rhizoctonia solani isolated from sugar beet. In: Proceedings of the American Society of Sugar Beet Technologists. 36th Biennial Meeting, March 2-5, 2011, Albuquerque, New Mexico. 2011 CDROM. Technical Abstract: Cucumbers are grown in rotation with sugar beets in some areas in Michigan but their interaction with important diseases affecting sugar beets is not well known. Cucumbers are known to be primarily susceptible to Rhizoctonia solani AG-4, but little is known about their susceptibility to AG 2-2 isolates that cause the most severe Rhizoctonia crown and root rot of sugar beet. The objective in this study was to determine if R. solani isolates obtained from sugar beet could cause belly rot in cucumber fruit. Cucumbers were placed in direct contact with soil that had been inoculated with AG 2-2 IIIB (1 isolate), AG 2-2 IV (1 isolate), AG 4 (2 different isolates), or a sterile ground barley control. After three weeks cucumbers were visually examined and given a Rhizoctonia belly rot rating on a scale of 0-5, with 0 indicating a healthy fruit and 5 being complete deterioration of the fruit. Average Disease Indices (DI) were calculated. AG 4 isolates produced DI of 2.7 and 3.5, AG 2-2 IIIB was 2.8, AG 2-2 IV was 1.8, and barley control was 0. While AG 4 has been reported as the primary Rhizoctonia pathogen of cucumber, it appears that both AG 2-2 types can cause significant damage to cucumbers with the tested AG 2-2 IIIB isolate causing as much damage as one of the AG-4 isolates. From this experiment it is clear that not only can cucumber act as a host for sugar beet isolates, but also that sugar beet isolates can cause belly rot in cucumbers. Therefore, farmers who use cucumbers in rotation with sugar beets need to be careful in managing their fields so as not to create a worsening Rhizoctonia problem for either of the cucumber or sugar beet crops.