Field efficacy of eco-friendly management practices against maize stem borers in spring maize at Rampur, Chitwan

Accepted: 17 Dec. 2020 A field experiment was conducted to determine the comparative efficacy of different eco-friendly management practices against maize stem borers, Chilo partellus (Swinhoe) and Sesamia inferens (Walker) in maize under field condition during spring season for two consecutive years, 2017 and 2018. The experiment was laid out in a randomized complete block design with four replications and seven treatments, namely: i) Trichogramma chilonis (Ishii) (egg parasitoids) @100000 eggs ha, ii) Nimbicidine 0.03% (Neemax)-commercial product of neem @ 3.0 mL L of water, iii) Spinosad 45% SC (Tracer) -bio-insecticide @ 0.5 mL L of water, iv) Bacillus thuringiensis10cfu mL (Mahashakti)-bio-insecticide @ 2 mL L of water, v) maize intercropping with cowpea (1:1 ratio), vi) Chlorpyrifos 20% EC (Dursban)chemical insecticide @ 2 mL L of water, and vii) Untreated control (without application) at the National Maize Research Program, Chitwan, Nepal. The efficacy study revealed that all the treatments significantly reduced leaf and stem injuries and increased grain yield over untreated check (p<0.05). The treatment, chlorpyrifos 20% EC was found effective with minimum percent infestation in both leaf (5.51%) and stem (1.86%) injury followed by spinosad 45% EC and T. chilonis respectively. Similarly, spinosad 45% EC gave significant result with the highest grain yield (4.66 mt ha) followed by Chlorpyrifos 20% EC (4.57 mt ha) and maize + cowpea intercropping (4.23 mt ha) as compared to untreated control (2.91 mt ha). Maize + cowpea (1:1) intercropping and release of T. chilonis were at par statistically and proved safer to natural enemies as compared to the chemical insecticides.