Microbial antagonists and resistance induced for the management of bacterial blight of anthurium

Abstract

An investigation was undertaken for exploring the potential of microbial antagonists and chemical activators for the management of bacterial blight of anthurium. Different isolates of the pathogen, Xanthomonas axonopodis pv. dieffenbachiae were collected and Xad 6, the most virulent one was selected for further studies. The microbial flora from the rhizosphere and phyllosphere of healthy anthurium plants from various locations were isolated and screened for their efficacy in inhibiting X. axonopodis pv.dieffenbachiae under in vitro conditions. Among the microbes obtained, isolates of Bacillus sp. (B16) and Talaromyces sp. (F8) were the most effective. Nutreint agar proved to be the best media for B16 and the antagonist was also non-pathogenic to anthurium. The potential of chemical activators in management of bacterial blight of anthurium was also investigated both under in vitro and in vivo conditions. The in vitro studies revealed that chemical activators had no direct action on the pathogen, conforming to one of the characteristics of an activator for inducing disease resistance in plants (Systemic acquired resistance, SAR). Among the chemical activators tested under in vivo conditions, 500ppm potassium phosphonate and 25ppm acibenzolar-s-methyl showed considerable effect in reducing the per cent disease intensity. The best treatments from the above studies and some other treatments which exhibited good results against bacterial blight of anthurium from previous works were studied in a green house trial on ten month old tissue culture anthurium plants of Cancan variety. The treatments included B16, F8, 500 ppm potassium phosphonate, 25 ppm acibenzolar-s-methyl, crude extract of neem cake, 0.15 per cent of turmeric powder + sodium bicarbonate (10:1) and 100 ppm streptocycline. The result indicated that the treatments, B16 (Bacillus sp) and 0.15 per cent of turmeric powder +sodium bicarbonate (10:1) were effective as they showed least bacterial blight intensity. So it can be concluded that, a prophylactic root dip and foliar spray of Bacillus sp. (B16) or turmeric powder + sodium bicarbonate (10:1) @ 0.15 per cent were equally effective in managing bacterial blight of anthurium. The role of chemical activators on the other hand in combating the disease was next only to microbial antagonists and ecofriendly material.