Influence of pesticides on the growth rate and plant-growth promoting traits of Gluconacetobacter diazotrophicus

The in vitro study to examine the effect of different pesticides on the growth and survival of Gluconacetobacter diazotrophicus strain PAL5 was carried out. Monocrotophos, Lindane and Dichlorvos had the most lethal actions against Gluconacetobacter grown on LGIP medium, while Endosulphan, Chlorpyriphos, and Malathion effects were intermediate. Herbicides generally appeared to have no adverse effect on the growth and survival of Gluconacetobacter in the medium except for the concentrations exceeding recommended rates. Fungicides, except Ridomil, had a slight effect on the growth of Gluconacetobacter at recommended dose. With the various pesticides used, the cell morphology was affected to a larger extent resulting in larger number of pleomorphic cells. Further their influence on the physiological traits like nitrogenase activity, indole-3-acetic acid, gibberellin A3 production, and phosphate and zinc solubilizing activity are discussed.