Poster: Biology & Disease Mgmt: Biological Control
179-P
Assessment of three Trichoderma species to protect cabbage from Clubroot
A. BOTERO (1), A. Cotes (2), C. García (3) (1) Universidad Nacional de Colombia, Colombia; (2) CORPOICA, Colombia; (3) Universidad Nacional deColombia, Colombia
Following reports that biocontrol agents are potential management tools for clubroot of crucifers, caused by Plasmodiophora brassicae, this research aimed at assessing one strain of each of three Trichoderma species: T. asperellum Th034, T. brevicompactum Th201 and T. koningiopsis Th003 with different number of applications in terms of disease reduction on ‘Delus’ cabbage. Experiments were conducted in growth chambers and infested fields. For growth chambers, two concentrations of the pathogen were used, and Trichoderma was applied once or twice; disease was measured 60 days after planting. For field experiments Trichoderma was applied once, seven or 15 times during the cycle, and evaluations were done quarterly. In growth chambers, disease reduction was observed only for the low pathogen concentration; the highest reduction was observed when T. koningiopsis and T. brevicompactum were applied once. Disease reduction by T. asperellum was proportional to the number of applications. Field results were not as clear cut as those from growth chambers; however, disease reduction was observed with T. asperellum, and again this reduction was proportional to the number of applications. In conclusion, T. asperellum shows potential for clubroot control when applied frequently, whereas one application of either T. brevicompactum or T. koningiopsis can be useful in disease management in low pathogen concentrations.