Effects of AMF- and PGPR-root inoculation and a foliar chitosan spray in single and combined treatments on powdery mildew disease in strawberry

Trials were carried out using, as a root inoculants, mixed Glomus spp. (G. mossae, G. caledonium, and G. fasiculatum) and Bacillus subtilis FZB24, and the plant activator N, O-carboxymethyl chitosan applied as a foliar spray. The treatments were applied singly and in combinations, on strawberry plants grown out of season in a greenhouse. Both fruit yield and runner production were reduced due to disease. Several of the treatments were found to have significant effects, increasing fruit number and yield, and runner production. Disease symptom severity was lowest in the B. subtilis FZB24 plus chitosan treatment. The treatments giving significantly higher fruit yield/number and runner production were inoculation with B. subtilis FZB24, and with B. subtilis FZB24 or AMF combined with chitosan spray. These treatments and a fungicide treatment, gave the same level of disease control.