ECOFRIENDLY MANAGEMENT OF COCONUT RHINOCEROS BEETLE GRUBS, ORYCTES RHINOCEROS LINNAEUS (SCARABAEIDAE: COLEOPTERA) USING BOTANICAL EXTRACTS UNDER LABORATORY CONDITIONK. Manivasagam, M. Muthuswami, T. Srinivasan and K.K. Kumar
Coconut rhinoceros beetle, Oryctes rhinoceros L. (Scarabaeidae: Coleoptera) is a serious pest which causes greatest impediment in the early establishment of juvenile palms. The experiment was conducted to test the insecticidal property of different botanical extracts (Aqueous extract) viz., Neem based products (Neem cake, Neem leaf, Neem oil), Vitex (Vitex negundo) leaf, veldt grape (Cissus quadrangularis) leaf, Holy basil (Ocimum sanctum) leaf and Sweet flag (Acorus calamus) Rhizome against the 2nd and 3rd instar grubs of Coconut Rhinoceros Beetle, O. rhinoceros. It was founded that Neem cake 30% was highly effective against Rhinoceros Beetle grubs that elicits 54.00% and 50.00% mortality in case of 2nd and 3rd instar grubs respectively. Followed by Neem cake, Neem oil shows good response of 49.33% and 40.67% mortality over 2ndand 3rd instar grubs. The mortality data fits good with the probit data in regard with chi-square (Ã·2) value. The lowest LC50 value (22.31%, 26.19%) was obtained in Neem cake treatment in both 2nd and 3rd instar respectively. Followed by Neem cake, Neem oil, Acorus calamus Rhizome extract, Neem leaf extract, Vitex negundo leaf extract, Cissus quadrangularis leaf extract and Ocimum sanctum leaf extract having median lethal concentrations of about 30.07, 52.86, 63.11, 74.37, 85.42 and 85.53%. In case 3rd instar followed by Neem cake, Acorus calamus leaf extract, Neem oil, Neem leaf extract, Vitex negundo leaf extract, Cissus quadrangularis leaf extract and Ocimum sanctum leaf extract having median lethal concentrations of 38.00, 54.71,72.79, 95.35,95.71and 99.60%. Thus, the mortality data and LC50 value shows among different treatment Neem Cake shows high efficacy then compared to the others. Hence, it can be utilized for the effective management of Rhinoceros beetle grubs in case of immature larval stages by using drenching method.