Compatibility Study of Azotobacter Species with commonly used Agrochemicals in India

Abstract

The present investigation was undertaken to study the compatibility
of Azotobacter spp. with commonly used agrochemicals in India. Azotobacter isolates were obtained from the Biofertilizer Laboratory and Biocontrol Laboratory of the National Institute of Plant Health Management (NIPHM), Hyderabad, India. Under laboratory conditions, Azotobacter failed to multiply at the field-recommended dose of fungicides such as Mancozeb 75% WP, Hexaconazole 5% EC, and Propiconazole 25% EC, as no colony formation was observed. However, at half the recommended dose, all the tested fungicides were found to be compatible with Azotobacter. The bacterium was able to multiply at both the field-recommended and half-recommended doses when inoculated with herbicides including Glyphosate 41% SL, 2,4-D Sodium salt 80% WP, and Pretilachlor 50% EC. Similarly, insecticides such as Fipronil 80% WG, Thiamethoxam 25% WG, and Quinalphos 25% EC were found to be compatible with Azotobacter at both dosage levels. Under field conditions, Azotobacter showed multiplication even at the field-recommended doses of fungicides, herbicides, and insecticides, indicating a differential response between laboratory and field environments. Agrochemicals that do not adversely affect the growth of microbial inoculants can be further evaluated and potentially used in combination with biofertilizers. The results suggest that Azotobacter is compatible with several commonly used agrochemicals and can be integrated into Integrated Pest Management (IPM) and Integrated Nutrient Management (INM) systems as a bio-input component.