Abstract
This study was conducted to find out the effect of some antagonistics bacteria isolates on Penicillium digitatum the causal green mould of citrus, collected from infected fruits in Rasht, Lahijan, Some – Sara, Fouman, Talesh and Astara in the Guilan province, Iran under in vitro conditions. Eighty eight bacterial isolates, from the surface of citrus fruit (cvs. Tamson and Shahsavary) infected by P. digitatum and antagonistic ability of 6 isolates of these bacteria (Gram negative) was demonstrated by using the dual culture method. According to biochemical and morphological tests, the six isolates were identified as Pseudomonas fluorescens. The effect of volatile metabolites produced by antagonistic P.fluorescens was found that all isolates, inhibited growth of P.digitatum in vitro. Culture filtrate and antibiotics from these isolates inhibited growth of the pathogen. Under refrigerating room conditions at 4°C, citrus fruits were treated against green mould disease by dipping cell suspensions (1 × 108 cfu/ml) of the bacteria and in Benlate, Rovral TS. fungicides (1000 ppm). Statistical analysis of data indicated that there existed significant differences between all antagonistic isolates and the control (P< 0.01). Storage for 25 days at 15°C in vitro or after 4 months at 4°C in refrigerating room conditions, mixture of isolate C4 and Benlate fungicide reduced green mould disease by 71.66 and 82.66 percent respectively.
