Nylon nets: a simple pest exclusion barrier technique to manage rhinoceros beetle menace in coconut plantations

Abstract

Oryctes rhinoceros (L.) is a major pest of palms worldwide. Seedlings and juvenile palms are more vulnerable to beetle damage and in severe cases, inflicting palm death. The present study was to develop a physical pest control technique for juvenile palms using nylon nets as a pest exclusion barrier. The unopened spear leaf with –two to four adjacent leaf bases were loosely wrapped with the nylon nets of different mesh size during June - December 2017 (N = 40). Results revealed that the damaged leaves were reduced from 61.02 to 7.53% (t = 17.23; p < 0.001). Further experiment was up scaled in 120 palms during June – December 2018 and the beetles trapped in nylon nets were recorded at weekly intervals. Nylon nets entrapped 618 adult beetles that comprised 61.80% females and 38.18% males with corresponding sex ratio of 1.61: 1. Thus, use of nylon nets as a pest exclusion barrier guarded the young palms from beetle attack and additionally acted as passive trap by entrapping 20.6 beetles/week/120 palms without any insecticidal intervention.