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 biolo gical control of Fusarium wilt of tomato by Penicillium oxalicum. The method consists in growing tomato plants in flasks with nutrient solut ion in a growth chamber. Plants were previously treated in the seedbed with a conidial suspension (10(7) conidia mL(-1)) of P. oxalicum 7 da ys before transplanting. Fusarium oxysporum f.sp. lycopersici (race 2) was added to the Hoagland solution just before transplanting. Differe nt concentrations and several isolates of F. oxysporum f.sp. lycopersi ci were tested. Using this method, plants showed typical symptoms of t he disease and the effect of the biocontrol agent was clear. Consumpti on of nutrient solution was reduced in diseased plants, and this reduc tion was diminished by treatment with P.oxalicum. Consumption of nutri ent solution was correlated with other disease-related parameters (AUD PC, weight of aerial parts, stunting) and was an easy and objective pa rameter to measure.