Effects of varying environmental conditions on biological control of Fusarium wilt of tomato by nonpathogenic Fusarium spp.
2002
A:PS
Details
Title
Effects of varying environmental conditions on biological control of Fusarium wilt of tomato by nonpathogenic Fusarium spp.
Author
Larkin, R.P.
Fravel, D.R.
Fravel, D.R.
Publication Date
2002
Call Number
A:PS
Summary
The influence of varying environmental and cropping conditions including day (22, 27, and 32 degree C) and night (16, 22, and 26 degree C) temperature, light (_500 and 250 uMol m-2 s-1), soil type, pathogen isolate, and race, and cultivar of tomato on biological control of Fusarium wilt of tomato by isolates of nonpathogenic F. oxysporum (CS-20 and CS-24) and F. solani (CS-1) was evaluated in greenhouse and growth chamber experiments. Liquid spore suspensions (106/ml) of the biological control isolates were applied to soilless potting mix at the time of tomato sowing, and the seedlings were transplanted into pathogen-infested field soil 2 weeks later. Temperature regimes ranging from 22 to 32 degree C significantly affected disease development and plant physiological parameters. Biological control isolate CS-20 significantly reduced disease at all temperature regimes tested, yielding reductions of disease incidence of 59 to 100% relative to pathogen control treatments. Isolates CS-24 and CS-1 reduced disease incidence in the greenhouse and at high temperatures, but were less effective at the optimum temperature for disease development (27 degree C). Growing plants under shade (50% of full light) versus full light affected some plant growth parameters, but did not affect the efficacy of biological control of any of the three biological control isolates. Isolate CS-20 effectively reduced disease incidence (56 to 79% reduction) in four different field soils varying in texture (sandy to clayey) and organic matter content (0 to 3.2%). Isolate CS-1 reduced disease in the sandy and loamy soils (49 to 66% reduction), but was not effective in a heavy clay soil. Both CS-1 and CS-20 were equally effective against all three races of the pathogen, as well as multiple isolates of each race (48 to 66% reduction in disease incidence). Both isolates, CS-1 and CS-20, were equally effective in reducing disease incidence (66 to 80% reduction) by pathogenic races 1, 2, and 3 on eight different tomato cultivars (Bonny Best, Marglobe, Rutgers, Better Boy, Miracle Sweet, Early Girl, Celebrity, and Big Beef) containing varying levels of inherent resistance to Fusarium wilt (susceptible, resistant to race 1, or resistant to races 1 and 2). These results demonstrate that both these Fusarium isolates, and particularly CS-20, can effectively reduce Fusarium wilt disease of tomato under a variety of environmental conditions and have potential for further development.
Journal Citation
v.92(11):1160-1166, PHYTOPATHOLOGY
Contact Information
harvest@worldveg.org
Record Appears in
Research > Published Articles