Biological control of tomato bacterial wilt disease by plant growth promoting rhizobacteria

Abstract

Abstract: In this study, the use of p lant g r owth p romoting r hizobacteria (PGPR) wasinvestigated as an alternative method to chemical control of tomato bacterial wilt disease. Atotal of 499 candidate bacterial isolates were isolated from 39 different rhizosphere- associated soils from different tomato growing fields in Adana, Antalya, Hatay, Osmaniye,Mersin ands Mugla provinces. Among these isolates, 30 candidate bacterial isolates wereinitially selected as PGPR which solubilize phosphorus and fix nitrogen. The most efficienteight candidate PGPR isolates were further assessed for to suppression of tomato bacterialwilt disease in in vivo pot experiments. In the pot experiments Y1.6.7 and N6.6.21 codedPGPR isolates reduced disease development by an average of 38 and 54 %, respectively.The most efficient two PGPR isolates and their combination were further used for fieldexperiments. Field experiments revealed that disease severity was significantly suppressedby an average of 43% by Y1.6.7.+ N6.6.21 coded PGPR treatment. PGPR isolates alsopromoted plant growth (plant height and stem diameter) at varying ratios in the infectedtomato plants.