Field-Level Susceptibility of Rice Varieties to The Asian Rice Gall Midge (Orseolia Oryzae) under Natural Infestation in Nalgonda District, Telangana, India
A. Bhargavi
Department of Biotechnology, Mahatma Gandhi University, Nalgonda, Telangana State-508 254, India.
Siva Ram Tejomoortula *
Department of Biotechnology, Mahatma Gandhi University, Nalgonda, Telangana State-508 254, India.
*Author to whom correspondence should be addressed.
Abstract
Host-plant resistance is the most sustainable option for managing the Asian rice gall midge, Orseolia oryzae. A three-year natural-infestation study (Kharif 2023–2025) evaluated the field-level susceptibility of four rice varieties—BPT 5204 (Samba Mahsuri), MTU 1010 (Cottondora Sannalu), Sheetal (WGL-3962) and KNM 1638 (Siddi)—in Appajipeta and Khajiramaram villages in Nalgonda District, Telangana. Pure-stand observation blocks were maintained under insecticide-free conditions. Silver shoot percentage (SS%) and plant damage were recorded fortnightly and classified using the IRRI Standard Evaluation System (SES) 0–9 scale. BPT 5204 recorded the highest three-year pooled SS% (16.58 ± 1.96%) and plant damage (42.50 ± 4.15%), reaching 28.40% SS at 60 DAT (SES Score 7, peaking at Score 9). MTU 1010 recorded 13.20 ± 1.58% SS (SES Score 7). In contrast, Sheetal recorded 2.42 ± 0.40% SS (SES Score 3, Moderately Resistant) and KNM 1638 recorded 0.77 ± 0.21% SS (SES Score 1, Resistant). Relative to BPT 5204, KNM 1638 and Sheetal reduced silver shoot damage by 95.36% and 85.40%, respectively, keeping infestation well below the 5% economic threshold level. These findings indicate the high vulnerability of popular commercial varieties and the strong field resistance of PJTSAU-recommended cultivars under Nalgonda conditions.
Keywords: Asian rice gall midge, Orseolia oryzae, rice, host-plant resistance, silver shoot incidence, IRRI Standard Evaluation System, natural infestation, varietal susceptibility, KNM 1638