Patterns in the Distribution and Abundance of the Post-Outbreak Population of the Coconut Leaf Beetle, Brontispa longissima (Gestro) (Coleoptera: Chrysomelidae) in Albay, Philippines

Abstract

Field monitoring of the coconut leaf beetle (CLB) population in old stands (more than 7 years old) and young stands of coconut (3-5 years old) was conducted in Albay Philippines where an outbreak of the pest occurred in 2006. The study was conducted to characterize the changes in the population of the CLB over time and space and to relate these changes to the infestation pattern, age of palms, development and reproduction of the pest, growth, and development of the coconut leaf. The spatial distribution of the CLB population as well as the infested palms were aggregated throughout the monitoring period based on the Index of dispersion and Lloyd’s mean crowding. Development time and reproduction of CLB is inferred to be synchronous with the emergence of each leaflet in the spear of coconut which has an average of 23 days before another leaflet emerges. This complemented the biology studies where CLB was able to complete from egg to adult in 34.33±2.59 and 32.00±0.93 days in females for both laboratory and greenhouse studies. The infestation of CLB was shown not to spread even if there was an increase in the population.