Biological Control Of Peach Gummosis By Bacillus Amyloliquefaciens J5

Fungal gummosis disease is an important disease on peach. In China this disease is mainly caused by Botryosphaeria dothidea (Moug.) CES&De Not., which belongs to the genus Botryosphaeria.Peach gummosis disease mainly harms to branches and is difficult to control. It always result a large, blackened, cankered area of bark tissueand gum exudation. In this study, we investigated the peach gummosis disease occurrence in Huazhong Agricultural University specimen garden from2010to2012. And the biological control potential of an endogenous bacterium Bacillus amyloliquefaciens J5was also studied.The investigation results showed that the disease incidence varies in different species of peach. Totally, The disease index is highest in nectarine and lowest in flat peach. The disease indexmaintained between20-50from April to October and the incidence is about80%. Both of them declined slightly in late July and early August.The antifungal spectrum of an endogenous bacterium strain J5, which was isolated by our lab, was detected. The results indicate that fermentation broth can inhibit the growth of a variety of pathogenic fungi, including B. dothidea. Biocontrol potential of J5was determined through branches incoculation. The results show that the J5can suppress the occurrence of peach gum disease during indoor inoculation test.To determine the antagonistic substance, J5’s culture filtrate was extracted with different organic extractants. After partitioning with carbon tetrachloride, the mycelial growth rate of B. dothidea was significantly inhibited on PDA tablets added the solvent fractions. Activity of the antagonistic substance in culture filtrates was stable even after incubation at121℃for up to30min. Culture filtrates treated with either both proteinase K or pepsin was still inhibitable to B. dothidea.The bacterium J5was marked with antibiotics (Rifampin) and injected into the peach tree and then the bacteria were isolated from peach after10months. Results showed that the marked J5strains can be isolated from different tissue and suggested that J5is an endogenous bacterium on peach.Currently very little literature has been reported in biological control of peach gum disease. This study may provide some reference for peach gum disease control by using endogenous bacteria.