A rapid laboratory method for assessing the biological control potential of Penicillium oxalicum against Fusarium wilt of tomato

A rapid, simple and reliable procedure was developed to evaluate biological control of Fusarium wilt of tomato by Penicillium oxalicum . The method consists in growing tomato plants in flasks with nutrient solution in a growth chamber. Plants were previously treated in the seedbed with a conidial suspension (10⁷ conidia mL⁻¹) of P. oxalicum 7 days before transplanting. Fusarium oxysporum f.sp. lycopersici (race 2) was added to the Hoagland solution just before transplanting. Different concentrations and several isolates of F. oxysporum f.sp. lycopersici were tested. Using this method, plants showed typical symptoms of the disease and the effect of the biocontrol agent was clear. Consumption of nutrient solution was reduced in diseased plants, and this reduction was diminished by treatment with P.oxalicum . Consumption of nutrient solution was correlated with other disease-related parameters (AUDPC, weight of aerial parts, stunting) and was an easy and objective parameter to measure.