Biocontrol agents and resistance inducers reduce Phytophthora crown rot (Phytophthora capsici) of sweet pepper in closed soilless culture

Twelve trials, in closed soilless culture under controlled conditions, were carried out to evaluate the efficacy of resistance inducers (based on K-phosphite and K-silicate used alone or combination), experimental biocontrol agents (Trichoderma sp. TW2, a mixture Pseudomonas FC 7B, 8B, 9B, Fusarium solani FUS25, PB26), commercial formulation Trichoderma gamsii + T. asperellum, against diseases caused by Phytophthora capsici sweet pepper. The products applied using three different protocols, effects incidence crown, stem root rots (% dead plants), disease development (area progress curve; AUDPC), plant fresh weights evaluated. Potassium phosphite, directly at standard P2O5:K2O, 1.30 1.05 g L-1) half rates, onto growing media, via nutrient solution, before infestation peat medium with P. capsici, provided best management dose-dependent manner, an 80% reduction for dosage both types application. These treatments also reduced proportions plants 47% from rate 62% rate, when solution substrate. partially percentage plants, 20–23%. No improvement control was observed combination while combined development, compared untreated controls. Biocontrol (BCAs), preventively, rots, similar better results than those asperellum gamsii. Among tested BCAs, FUS25 most consistent (60–65%) gave increased weights. All BCAs trend pressures. least AUDPC values, non-treated controls, followed strains TW2. indicate potential potassium phosphite pepper grown systems.