Bionomics and chemical control of leaf miner in groundnut under semi-arid conditions

Abstract:

The groundnut leaf miner, Aproaerema modicella (Deventer), is a micro-lepidopteran pest whose larvae feed inside folded leaflets, creating characteristic blotch mines that can reduce photosynthetic area by 30 to 60 percent in severe outbreaks. Despite its economic importance in semi-arid groundnut production zones, detailed biological data on this pest under the specific climate of southern Gujarat remain scarce. This research documented the bionomics of A. modicella and evaluated six insecticidal treatments for its management during kharif 2022 and 2023 at Navsari Agricultural University, Gujarat. Life history observations on caged plants revealed a total developmental period of 21.5 ± 2.1 days (egg: 2.1 days, larval instars L1-L3: 8.4 days, pupa: 6.7 days, adult longevity: 4.3 days). Peak larval activity occurred during September across both seasons, coinciding with temperatures of 28-32 °C and relative humidity above 75 percent. Among insecticidal treatments tested in a randomized block design, chlorantraniliprole 18.5 SC at 30 g a.i. ha⁻¹ gave the highest larval reduction (84.7%) at 7 days after spraying (DAS), followed by emamectin benzoate 5 SG at 11 g a.i. ha⁻¹ (79.3%). Neem-based formulation (azadirachtin 1500 ppm) achieved 53.8 percent control. Pod yield was highest in the chlorantraniliprole treatment (2.18 t ha⁻¹) compared to the untreated check (1.24 t ha⁻¹). Two sprays—the first at economic threshold level and the second at 15-day intervals—provided season-long protection and are recommended for integrated management of A. modicella in semi-arid groundnut systems.