BIOLOGICAL CONTROL OF SCLEROTINIA MINOR ON LETTUCE USING TRICHODERMA AND CONIOTHYRIUM SPECIES
Sclerotinia is a major disease problem in vegetable production, including lettuce, green bean and cabbage in Victoria, Australia. It is caused by the soilborne fungal pathogens Sclerotinia minor and S. sclerotiorum. There are currently limited management options available to control Sclerotinia in Victoria. Biological control with biocontrol agents of Sclerotinia species has been proposed as one potential and IPM compatible control option for Sclerotinia. The objective of this study was therefore to evaluate six biological treatments, including three fungal isolates with proven antagonistic activity against Sclerotinia species, for their ability to control S. minor infection of lettuce in five field experiments. Biological treatments were evaluated against the fungicide procymidone. Procymidone significantly reduced disease (lettuce drop) by 89% at one site with high disease incidence (70.5%) and by 83-92% at another four sites with low disease (4-12%). All biological treatments failed to control S. minor infection at the high disease site. In low disease pressure sites, however, some of the biological treatments provided some useful control of S. minor. Trichoderma hamatum 6sr4, applied to the potting mix of lettuce transplant and as a combined application (transplant and soil applications at transplanting), significantly reduced disease by 78% and 83%, respectively, at two sites. Control by T. hamatum 6sr4 was similar to that provided by procymidone at these two sites. Similarly, C. minitans A69, applied as single (transplant) and combined (transplant plus soil) applications, also gave significant disease reductions of 45% and 51%, respectively, at one site in which soil applications of C. minitans (Contans®) and Nutri-life® also gave significant disease reductions (48-55%). The potential use of biocontrol agents as a management tool for S. minor lettuce drop is discussed.
Villalta, O.N., Wite, D., Hunt, J., Stewart, A. and Porter, I.J. (2012). BIOLOGICAL CONTROL OF SCLEROTINIA MINOR ON LETTUCE USING TRICHODERMA AND CONIOTHYRIUM SPECIES. Acta Hortic. 944, 51-58
lettuce drop, biocontrol agent, potting mix, lettuce transplant, fungicide