Combining Pest Repellent Plants and Biopesticides for Sustainable Pest Management in Chinese Kale

The objective of this investigation was to study the use of pest repellent plant (PRP) species and biopesticides for sustainable pest management in Chinesekale(Brassica oleracea L. var. alboglabra Bailey). Ten selected treatments composed of three PRP species namely citronella grass - (CG) [Cymbopogon nardus L. (Rendle)], sweet basil - (SwB) (Ocimum basilicum L.) and sacred basil - (SaB) (Ocimum sanctum L.)] were intercropped with Chinese kale, integrated with two commonly used biopesticides, viz. Bacillus thuringiensis (Bt) and neem extract (Azadirachta indica) and a control were tested in a randomized complete block design (RCBD) with 3 replicates. The insect pest species infested in Chinese kale and their populations, % pest damage, fresh weight and quality of yield were investigated. The results showed that diamondback moth - (DBM) [Plutella xylostella (Linnaeus)] density was lowest in CG alone, CG+SaB, SwB+biopesticides and SaB+biopesticides, relatively low in SwB alone, CG+SaB+SwB, and CG+biopesticides, and moderate in biopesticides and sacred basil alone, and highest in the control. The densities of common cutworm - (CCW) [Spodoptera litura (Fabricius)], cabbage webworm - (CWW) [Hellula undalis (Fabricius)] and flea beetle - (FBT) (Phyllotreta sinuata Steph.) were not significantly different among treatments. The overall pest damage was lowest in CG+biopesticides treated plots followed by SwB+ biopesticides, SaB+biopesticides and biopesticides alone, and CG+biopesticides gave the best quality of yield of Chinese kale, and hence such combinations could be integrated for managing crucial insect pests, i.e. DBM and to minimize/avoid the use of highly toxic synthetic pesticides in Chinese kale.