Vol. 10, Special Issue 11 (2021)

Author(s):
R Sunitha Devi, A Venkat Reddy and S Dhurua

Abstract:
The Asian rice gall midge, Orseolia oryzae (Wood-Mason) (Diptera: Cecidomyiidae) is a serious pest of rice (Oryza sativa L.) in India. Seven distinct biotypes of the Asian rice gall midge population have been characterized so far from different parts of India. Warangal gall midge population designated as biotype 4M. In order to identify the prevailing rice gall midge biotypes, a study was carried out under natural field conditions at RARS, Warangal. A set of 16 standard rice differentials representing five groups already identified to characterize the prevailing rice gall midge biotypes in the country were evaluated against gall midge population. Based on earlier studies, resistance against biotype 4M confirmed only through the IV group differentials with resistance genes viz., gm3, Gm4 and Gm8. The results of present study revealed that the reaction of differential of group I, II, III and V (TN1, Susceptible check) showed susceptibility during both the years i.e., kharif, 2011-12 and kharif, 2012-13 whereas, reaction of group IV differentials was not stable and changed year after year. Based on this study, it was found that the biotype at RARS, Warangal was not following any prescribed pattern of the seven identified biotypes, indicating a change in the reaction pattern of standard differentials to gall midge biotype 4M with virulence against the resistant group IV rice differentials.