Biological Control of Alternaria Rot of Tomato by Two Bacterial Strains, Pseudomonas fluorescens UTPf68, and Bacillus subtilis UTB96

Poor packaging and improper management causes fruits get bruised and squeezed، allowing for different types of rots to develop when the necessary favorable growth conditions available. Tomato fruit is beset with problems of both field and storage rot. Throughout the present study، two biocontrol bacteria Pseudomonas fluorescens UTPf68، and Bacillus subtilis UTB96 the large scale production of which had been successfully carried out in industrial bioreactor were tested against some isolated tomato post harvest pathogens، in either in vitro or in vivo conditions. Alpha Dual culture results indicated that B. subtilis UTB96 inhibited mycelial growth of Alternaria alternata and of Penicillium spp. for about 68. 7 and 81. 7 percent respectively. Also، P. fluorescens UTPf68 was shown to prevent the mycelial growth of A. alternata and of Penicillium spp. by about 62. 2 and 24. 3 percent respectively. A substantial potential of the bacterial strains، in preventing the growth of fungus A. alternata on tomato fruit was finally observed. The bacterium B. subtilis UTB96 reduced rot development of tomato fruits caused by A. alternate for about 92. 5 percent. Meanwhile، bacterium P. fluorescens UTPf68 inhibited the mycelial growth of the postharvest pathogen A. alternata on tomato fruits by about 76. 5 percent. The results of this study plus future complementary researches can help the development and application of large scale biological control intended to reduce the post harvest incidence of diseases.