Efficacy of different botanicals against subterranean insect pests of potato

Abstract

A field experiment was carried out at instructional cum research (ICR) farm, Assam Agricultural University, Jorhat, Assam in the year 2017-18, to evaluate the efficacy of different bio-pesticides viz., Neem oil, Jatropha oil and Karanj oil, against Agrotis ipsilon and Dorylus orientalis. Potato variety ‘Kufri Jyoti’ was selected for the research. The highest per cent reduction of cut worm population/pit by bio-pesticides was observed in neem oil @ 5% drenching (64.23%) at 15 days after treatment followed by Karanj oil drenching (61.54%), Jatropha oil drenching (56.54%) and Karanj oil spraying (56.54%). The lowest per cent reduction was recorded in jatropha oil @ 2ml/lit spraying at fifteen days after treatment (48.85%). The lowest per cent Hulm cut recorded among the bio-pesticides was neem oil @ 5% drenching at fifteen days (4.50%) and thirty days (9.01%) after treatment. The highest per cent Hulm cut was observed in the treatment jatropha oil @ 2 ml/lit spraying at fifteen days (8.40%) and thirty days (18.48%) of treatment. On the other hand, highest per cent reduction of red ant population (mounds) by bio-pesticides was observed in neem oil @ 5% drenching at 15 days after treatment (67.65%). The lowest per cent reduction was recorded in karanj oil @ 2ml/lit spraying at 15 days after treatment (51.17%). However, amongst all the bio-pesticides, lowest per cent tuber damage caused by the A. ipsilon and D. orientalis were observed neem oil drenching @ 5% (14.93% and 12.21%) in both weight basis and number basis and highest per cent tuber damage was observed in plot treated with jatropha oil spraying @ 2ml/lit (19.79% and 17.13%) in both weight basis and number basis.