Field-Level Susceptibility of Rice Varieties to The Asian Rice Gall Midge (Orseolia Oryzae) under Natural Infestation in Nalgonda District, Telangana, India

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.