ABSTRACT

This study evaluated the effectiveness and economic viability of drone and knapsack sprayers for controlling rice leaf folder, Cnaphalocrocis medinalis (Guenee) and rice ear head bug, Leptocorisa oratorius (Fabricius) in paddy fields. Study was conducted at ICAR-Krishi Vigyan Kendra, Malgi Farm, Karnataka, during Kharif 2023-24, Fipronil 5% SC and Profenophos 50% EC were applied with both spraying methods. Key parameters included pest control, impact on beneficial insects, phytotoxicity and pesticide residues.
Drone spraying of Fipronil 5% SC reduced leaf folder populations by 66.96 and 65.96 per cent in the first and second spray compared to 59.14 and 58.72 per cent with knapsack sprayer. For rice ear head bugs, drones reduced populations by 65.21 and 76.95 per cent, compared to 59.03 and 70.75 per cent with knapsack sprayers. Profenophos 50% EC was less effective in both methods.
Beneficial insects like spiders, coccinellids, dragonflies and damselflies were more abundant in control plots, followed by drone-sprayed plots. No significant phytotoxicity was observed. Pesticide residue levels were lower in drone-sprayed plots compared to knapsack sprayed plots. Fipronil residues were 0.092 mg/kg in straw and 0.033 mg/kg in grain, compared to 0.112 mg/kg and 0.034 mg/kg with knapsack sprayers. Profenophos residues were also lower with drones (0.122 mg/kg) than knapsack sprayers (0.128 mg/kg).
Drone application of Fipronil 5 % SC yielded the highest B:C ratio of 2.04 compared to B:C ratio of 1.99 and 1.56 with knapsack sprayers and untreated check, respectively. Overall, drones exhibited better pest control and preservation of beneficial insects with lower pesticides residues making this a more sustainable and cost-effective option for pest management in paddy.