Efficacy of botanicals against major insect pests of cabbage (Brassica oleracea var capitata)

A study was conducted to test the efficacy of different neem products, viz., pulverised neem seed powder extract (PNSPE), pulverised neem seed powder formulation (PNSPF), neem soap and neem cake petrol-water extract (NCPE), and synthetic insecticides against the insect pests of cabbage at the Indian Institute of Horticultural Research (IIHR), Bangalore during rabi 2012–13. It was found that PNSPE and PNSPF treatments recorded significantly less diamond back moth (DBM) than other botanicals and chemical insecticides except spinosad. On other hand, botanicals such as PNSPF, PNSPE and NCPE were found to be on par with the chemical insecticides in reducing leaf webber, recording very low incidence. In case of H. erysimi, PNSPF recorded the lowest incidence (4.67 aphids/8 plants) than any other treatment plots, with a significant difference over the synthetic chemical insecticides such as indoxacarb (41.33 aphids/8 plants), spinosad (75.00 aphids/8 plants) and flubendiamide (61.33 aphids/8 plants). Whereas, incidence of Brevicoryne brassicae was found to be more in chemical treated plots such as spinosad and flubendiamide than those received PNSPF and PNSPE. Population of Cotesia plutellae, larval parasitoid of DBM was ranged from zero and 7.67 in spinosad, but there was no statistical significant difference found among different treatments. All the treatments were superior to control plots in terms of yield and marketable heads. Although highest yield was recorded in PNSPE (76.17 t/ha), PNSPF (73.15 t/ha) and other insecticide treatments, like spinosad (76.37 t/ha), flubendiamide (61.97 t/ha), there was no significant difference among them. This study showed that PNSPF and PNSPE can be used as alternatives to the synthetic insecticides in managing DBM and aphids.