Different Strategies to Control Potato Brown Rot Disease

The aim of the present study was to evaluate the antibacterial activity of four different groups of treatments i.e., five antagonistic bacterial isolates; two species of Trichoderma; three species of Cyanobacteria and three types of Nanoparticle materials (NPs) against the growth of Ralstonia solanacearum, the causal agent of potato brown rot disease, in vitro and their effect on the disease suppression, as well as the plant growth under greenhouse conditions. The changes in some chemical constituents of the treated plants were also estimated. Fourteen virulent isolates of the pathogen isolated from infected potato tubers were used in this study. Identification tests confirmed that the 14 isolates belonged to R. solanacearum.In vitro experiments, five antagonistic bacterial isolates Acinetobacter baumannii (PD 3138), Bacillus cereus (STDF 2905/31), Bacillus ST1, Bacillus ST2 and Bacillus ST3 were suppressive to the growth of R. solanacearum. The highest inhibition zone of 12.39 mm was recorded for B. cereus. The cultural filtrates of T. harzianum and T. viride inhibited R. solanacearum growth. The higher inhibition zone diameter of 8.00 mm was recorded for T. harzianum .Three Cyanobacterial species namely: Nostoc muscorum, Spirulina platensis and Anabaena flos-aquae were used. The most suppressive cultural filtrate, against R. solanacearum growth, was A. flos-aquae with 13.7 mm inhibition zone. Five concentrations of three Nanoparticles i.e., zinc oxide, iron oxide and alloy of both, were tested against the pathogen growth. The highest inhibition zone of 29.50mm was observed for zinc oxide at 2 mg/ml. While, the least inhibition zone of 5.81 mm was observed for iron oxide at 0.2 mg/ml.In vivo experiments, all applied treatments significantly reduced the bacterial wilt incidence. In loamy sand soil, the Trichoderma group was more effective than the antagonistic bacterial isolates group .The superior of each group was T. harzianum and B. cereus that decreased the wilt severity to10.00 and 18.33%, respectively. In ...