Ground wild cucumber fruits suppress numbers of Meloidogyne incognita on tomato in microplots

Ground wild cucumber (Cucumis myriocarpus) fruits were evaluated as a soil amendment in microplots infested with the root-knot nematode, Meloidogyne incognita. Effects of the amendment on nematode numbers, growth of tomato (Lycopersicon esculentum), soil electrical conductivity, and soil pH were evaluated during spring 1999 and again during fall 2000. Treatments included an untreated control, M. incognita-infested soil, C. myriocarpus-amended soil, and C. myriocarpus-amended + M. incognita-infested soil, arranged in a randomized complete block design with 15 replicates. Seedlings were inoculated with nematodes and treated with amendment (0.71 mt/ha) one day after transplanting and plants were harvested 83 days later. Relative to nematodes alone, C myriocarpus-amended + M. incognita-infested soil had 73-83% and 49-68% fewer nematode numbers in roots and soil, respectively. This treatment increased plant height, dry matter weight, fresh fruit weight and soil electrical conductivity by 13-34%, 76-135%, 226-538% and 36-38%, respectively. Nematodes alone reduced soil pH, whereas C myriocarpus amendment did not affect soil pH nor leaf nutrient elements. Amendment with C myriocarpus increased soil electrical conductivity in both spring and fall experiments. Results indicated that C. myriocarpus fruits have potential as an organic amendment for managing M. incognita in tomato production.