Bioefficacy studies of compatible combinations of different agrochemicals in cotton

Abstract

Five commonly used insecticides (contact and systemic), two fungicides, one chemical and two fertilizers in forty combinations were tested at their recommended doses for its physical, chemical compatibility, phytotoxicity and bio efficacy on cotton crop at Regional Agricultural Research Station, Nandyal during Kharif, 2016-17. All the agro chemicals tested were physically and chemically compatible. In all the 42 combinations, though there was no much change in pH values of individual chemicals and in combination with other chemicals, the EC values of KNO3 and its combination with other chemicals were higher. Phytotoxicity symptoms such as leaf epinasty, leaf hyponasty, necrosis and scorching were not observed in all the combinations tested. Among the combinations, thiamethoxam alone, Flonicamid + urea, Flonicamid + propiconazole, thiamethoxam + urea and monocrotophos + KNO3 reduced the leafhoppers population by 55.73, 55.05, 54.17, 53.77 and 53.71% after 3 days after the spray. However, Flonicamid + urea and Flonicamid + propiconazole continued to show their efficacy even after 5 days after spray by recording 35.86 and 33.08 % reduction in leafhopper population.