Ecological engineering cropping methods for enhancing predator, Cyrtorhinus lividipennis (Reuter) and suppression of planthopper, Nilaparvata lugens (Stal) in rice- weeds as border cropping system
K Chandrasekar, N Muthukrishnan and RP Soundararajan
Weed species were raised as border crops in and around rice field (var.CO 51) to enhance the activity of predatory mirid bug, Cyrtorhinus lividipennis (Reuter) and to mitigate brown planthopper (BPH), Nilaparvata lugens (Stal). Echinochloa colonum (L.), Echinochloa crusgalli (L), Cyperus difformis (L.), Ammannia baccifera (L.), Eclipta alba (L) and Marsilea quadrifolia (L) were used as border crops. The attraction of C. lividipennis towards different leaf and flower sample of weed plant were also studied through eight-armed olfactometer under laboratory assays. Results revealed that mean population of mirid bugs and BPH on rice crop varied from 1.85 to 4.47 and 2.42 to 4.45 nymphs and adults per hill. Rice + E. colonum border cropping system significantly influenced for the maximum population of C. lividipennis on rice (4.47/hill) along with highest occurrence ratio (0.89), minimum population of BPH (2.42/tiller) and more CB ratio (1:1.41). This was followed by rice + E. crusgalli, rice + C. difformis and rice + A. baccifera border cropping systems that recorded with mean population of 4.23, 3.94 and 2.95 mirid bugs per hill on rice respectively. Rice + E. alba border cropping system observed with less population of mirid bugs (2.42/hill) on rice where as the mirid population in rice alone was 1.85/hill. Similarly, population of mirid bugs on border crops ranged from 0.71 to 3.99 per hill. Maximum mirid bug population (3.99/plant) was observed on E. colonum border crop. E. crusgalli and C. difformis registered 3.71 and 3.43 mirid bugs per plant respectively. A. baccifera, E. alba and M. quadrifolia had mirid populations of 1.71, 1.29 and 0.71 per plant. This study concluded that E. colonum and E. crusgalli can be used as border crops in rice ecosystem to enhance the activity of mirid bugs. In olfactometer studies, mirid bug attraction was higher towards E. crusgalli leaf (3.81) and flower (4.06) samples.
K Chandrasekar, N Muthukrishnan, RP Soundararajan. Ecological engineering cropping methods for enhancing predator, Cyrtorhinus lividipennis (Reuter) and suppression of planthopper, Nilaparvata lugens (Stal) in rice- weeds as border cropping system. J Entomol Zool Stud 2017;5(5):1778-1782.