Resistance to fruit rot caused by Rhizoctonia solani. Rating scale: 1 = resistant, 9 = susceptible. Cucumber accessions were evaluated for Rhizoctonia fruit rot resistance by the detached fruit method in which cucumbers were placed on a soil bed infested with Rhizoctonia solani inoculum. Fruits were collected several times per season with the goal of representing each accession with 10 to 30 fruit. A maximum of 10 fruit were collected on one sampling date. Unripe fruits of approximately 45-50 mm diameter were selected, avoiding fruits that were too young or too old. Promising accessions were tested for two or three years to reduce possible environmental influences. Inoculum was produced by growing R. solani mycelium on a substrate of corn meal, sand and horticultural Perlite. The substrate contained 20 g yellow corn meal, 500 mL fine white sand, 500 mL Perlite, and 220 mL deionized water. The mixture was sterilized by autoclaving in polypropylene jars. Three agar plugs of mycelium were added to each jar and incubated for 7-9 days at 270C before use. Transite benches were filled with a 5 cm layer of moist masonry sand, and overlaid with 0.5 to 1 cm of screened, autoclaved field soil. The soil was covered with inoculum at the rate of 175 g per m2, watered lightly and covered with a plastic sheet for 24 hours at 25oC to 27oC. Freshly picked fruit were washed and placed in firm contact with the soil, lightly sprinkled with water and covered with plastic for one night. Disease ratings were made after 6 to 7 days with each fruit scored as resistant (rating =1), intermediate (rating =5), or susceptible (rating =9). A rating of 1 corresponded to no visible infection on the undersurface of the fruit. Fruits with a rating of 5 had restricted crater-like lesions on the undersurface, but little spread. This was considered to be a moderately resistant reaction. A rating of 9 corresponded to an undersurface that was well-rotted. Several accessions showed high levels of resistance in repeated tests, including PI 165509, PI 197086, PI 250147, PI 271328, and PI 390261.