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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Publications at this Location » Publication #286255
Title: The effect of transitional organic production practices on soilborne pests of tomato

Author
item Chellemi, Daniel
item Rosskopf, Erin
item Burelle, Nancy

Submitted to: Journal of Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2013
Publication Date: 8/1/2013
Citation: Chellemi, D.O., Rosskopf, E.N., Burelle, N.K. 2013. The effect of transitional organic production practices on soilborne pests of tomato. Journal of Phytopathology. 103(8):792-801.

Interpretive Summary: Certified organic crop production has increased dramatically over the last decade to meet the demands of a growing global market. Expanding the availability of certified organic farmland has not kept pace with the increasing market demand. Creating new organic farms in the Florida Everglades Watershed (FEW) is difficult due to competition with urban development, wetlands conservation, and native habitat restoration. Converting existing conventional vegetable farms in the FEW to certified organic farms is a more plausible approach for meeting the growing market demand. Many farmers are reluctant to switch to organic production due to the risk of pest resurgence following the required transitional period. The objective of this study was to ascertain the effect of a 2 yr organic transitional period comprised of urban plant debris (UPD) and broiler litter (BL) applied under a continued tomato monoculture or an alternative crop rotation on soilborne diseases and pests of tomato. The results obtained from this study support the view that crop rotation during the transitional period from conventional to organic agriculture is critical to mitigating the resurgence of soilborne pests. Differential interactions were observed between the transitional cropping system employed and the source/composition of organic soil amendment in regards to damage by root-knot nematodes and the incidence of bacterial wilt of tomato. The results illustrate the importance of a systems-based approach to implementing transitional organic practices that recognize their interactive effects on resident soil disease and pest complexes.

Technical Abstract: The perceived risk of pest resurgence upon transition from conventional to organic-based farming systems remains a critical obstacle to expanding organic vegetable production, particularly where chemical fumigants have provided soilborne pest and disease control. Microplots were used to study the effects of a 2-yr transitional period that included several organic soil amendment and cropping sequences on the incidence of bacterial wilt of tomato (Solanum lycopersicum) caused by (Ralstonia solanacearum), purple nutsedge (Cyperus rotundus) reproduction, root galling by Meloidogyne incognita, and soil nematode populations. Continuation of a tomato monoculture during the transitional period resulted in a disease incidence of 33%, as compared to 9% in plots rotated with sunn hemp (Crotalaria juncea) and Japanese millet (Echinochloa crusgalli var. frumentacea). Combining annual applications of urban plant debris with continued tomato monoculture increased bacterial wilt incidence to 60%. The benefits in disease reduction from 2 years of crop rotation extended into to a second tomato production season, where bacterial wilt declined from 40% in tomato monoculture plots to 17%. Continued tomato monoculture also contributed to significantly higher levels of tomato root galling resulting from root-knot nematode infection when compared to tomato roots from plants following a cover crop regime. Nutsedge tuber production was significantly increased plots amended with broiler litter. The results illustrate the importance of a systems-based approach to implementing transitional organic practices that recognize their interactive effects on resident soil disease and pest complexes.