Assessment and evaluation of different treatment schedules against plant and tuber damage caused by soil pests on potato

Bio-efficacy of various treatment schedules, viz T₁ (phorate + chlorpyriphos + imidacloprid + cartap hydrochloride), T₂ (imidacloprid + acephate + chlorpyriphos + cypermethrin), T₃ (phorate + chlorpyriphos + azadirachtin + Bacillus thuringiensis var. Kurstaki), T₄(Bacillus thuringiensis var. Kurstaki + azadirachtin), T₅ (phorate + imidacloprid + chlorpyriphos + cypermethrin), T₆ (phorate + azadirachtin + Bacillus thuringiensis var. Kurstaki) and T₇ (control) were evaluated against Agrotis ipsilon (Hufner) and mole cricket, Gryllotalpa africana, P.de. Beau. in single potato variety, Kufi Chandramukhi during rabi season of two potato-growing years in 2013–2014 and2014-2015 from November to February. The percentage of plant (shoot) damage was found low in T₁ (5.82–5.87%), than by T₃ (6.12–6.49%), T₂ (6.86–6.92%), T₅(7.31–7.62%), T₆(8.21–8.81%), T₄ (8.61–9.32%) and T₇ (10.70–11.13%) respectively. Similarly percentage of tuber damage of potato was noted highest in T₇ (34.29–43.90%) and it was lowest in T₂ (13.15–15.66%). Maximum marketable yield (t/ha) of potato tubers was obtained in T₂ (26.28–26.80 t/ha), which was succeeded by T₁ (26.19–26.92 t/ha) than other treatments and it was recorded minimum in control T₇(11.17–12.69 t/ha). Maximum cost-benefit ratio (CBR) was recorded in T₅ (1: 2.03–1: 2.04) while it was found minimum in T₆ (1: 1.11–1: 1.17). Among the different treatment schedules T₅ and T₂ were most effective in increasing marketable yield of potato tubers and reduction of soil pest incidence over control T₇ and also over other treatments.