Role of Aspergillus as a biocontrol agent

Soil samples collected from different locations exhibited 9 isolates of two genera capable of degrading chitin on colloidal chitin agar media. Based on morphological and cultural characteristics isolates were categorised as four of Aspergillus niger (AN1 toAN4) and five of Aspergillus flavus (AF1 to AF5).

All the isolates were found effective against Fusarium udum, Rhizoctonia bataticola and Sclerotium rolfsii, confirmed by dual culture technique. The isolate AN3 ofAspergillus niger from Chandur and AF4 ofAspergillus flavus from Borgaon exhibited maximum antagonistic activity against F. udum inhibiting the pathogen by 84.28 and 87.63, per cent respectively. R. bataticola was inhibited by 69.62 and 82.07 per cent respectively by AN3 and AF5. In case of S. rolfsii, AN3 and AF5 exhibited maximum percent growth inhibition i.e. 69.61and 81.05 percent respectively. Fungicide Carboxin + Thiram and Thiram alone inhibited the growth ofA.niger by approximately 90% in all isolates. A.flavus isolates were inhibited by 100% due to Carboxin + Thiram and Carbendazim. Overall insecticides and weedicides were less toxic to all the isolates compared to fungicides.