Rice Stem Gall Midge (Indian Rice Gall Midge)

📖 Description

Rice Stem Gall Midge (Orseolia oryzae) is one of the most destructive pests of rice in the Indian subcontinent, particularly severe in rice belts of Andhra Pradesh, Telangana, Madhya Pradesh (Chhattisgarh region), Maharashtra, Odisha, Karnataka and Tamil Nadu where rice is grown on over 44 million hectares. The pest is endemic in ‘gall midge zones’ of central and southern India where it causes annual losses exceeding ₹500 crore. The larva is the destructive stage — it feeds inside the rice stem at the growing point, inducing characteristic gall formation that prevents panicle development. Affected tillers produce the characteristic ‘silver shoot’ or ‘onion shoot’ symptom — an elongated, tube-like, silvery-white shoot that fails to produce a panicle. Each affected tiller represents a direct yield loss (no grain produced). The pest is particularly severe in late-planted rice (October-November plantings) and in irrigated rice with excessive nitrogen. IPM with resistant varieties (carrying Gm gene — most effective preventive measure), conservation of the specialist parasitoid Platygaster oryzae (which can parasitize 60-80% of larvae when broad-spectrum insecticides are avoided), need-based systemic insecticide application at 30 and 45 DAT (most critical timing — before larvae induce gall formation), and avoidance of late planting provides effective control. The pest has multiple biotypes in India (at least 6 biotypes identified), and resistant varieties must be selected based on the local biotype — a variety resistant to one biotype may be susceptible to another. Rotation of resistant varieties across biotypes is critical to prevent biotype shifts that overcome resistance.