BIOLOGY AND POPULATION DYNAMICS OF ADULT Sagalassa valida WALKER, 1856 (Lepidoptera: Brachodidae), THE OIL PALM ROOT BORER IN COLOMBIA

Abstract

Sagalassa valida is a pest of economic importance because the larval stage feeds on the root system of the oil palm. In this investigation, the life cycle, the population dynamics of the adults, and their natural enemies were determined through biweekly samplings for 43 months in two lots of oil palm; located in the Central and Western Zone of Colombia. It was determined that the life cycle of S. valida is 64.1 days on average; the duration of each stage was: egg 9.2 ± 0.5 days, larva 38.1 ± 4.9 days (five instars), prepupa 2.9 ± 1.1 days, pupa 13.9 ± 1.1 days and adult 12.3 ± 4.3 days. The adults of S. valida were present in the two zones during the study; using Spearman’s correlation index, it was determined that in the Central Zone, the precipitation presented a direct and significant correlation with the variables: number of males ( ρ = 0.24; P = 0.023) and the total number of adults ( ρ = 0.21; P = 0.044). Ten natural enemies of S. valida and 14 weeds were identified in the study areas. This information is essential to implement an efficient management strategy for S. valida in plantations.