Chemo-prospecting Cleistanthus collinus, Lantana camara and Strychnos nux-vomica for rice pest management under laboratory conditions

Abstract

Cleistanthus collinus Roxb., Lantana camara L. and Strychnos nux-vomica L. are abundantly available in tropical countries and are being used for pest management as an Indigenous Technical Knowledge. The present study decoded the biochemical constituents of these species and tested the efficacy of these plant products against major rice insect pests and diseases. Significantly higher phenol content and antioxidant activity (2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2-Azinobis (3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) assay) were found in C. collinus water extract, whereas S. nux-vomica extract had higher flavonoids. The major chemical constituents of C. collinus, L. camara and S. nux-vomica were 1,2,3-Benzenetriol, β- Phellandrene and Phytol, respectively. Water extract of C. collinus had significantly reduced the insect pests (brown planthopper, Nilaparvata lugens Stål and gall midge, Orseolia oryzae Wood-Mason) and diseases (brown spot, Helminthosporium oryzae and bacterial leaf blight, Xanthomonas oryzae pv. oryzae). In contrast, S. nux-vomica water extract was most effective against the pathogens causing blast, Magnaporthe oryzae and sheath blight disease, Rhizoctonia solani in rice. The secondary metabolites, namely, 1,2,3-Benzenetriol, Neophytadiene, n-Hexadecanoic acid, Phytol etc. present in C. collinus extract reported to have biocidal activities against number of crop pests. As C. collinus has been listed as ‘vulnerable’ in the International Union for Conservation of Nature (IUCN) red list, it can be promoted as a viable component in Integrated Pest Management (IPM) of rice for its conservation and economic utilization.