LIFE CYCLE, FOLIAR CONSUMPTION AND DAMAGE IN FRUITS OF MELON BY Diaphania hyalinata (L) (LEPIDOPTERA: PYRALIDAE)

Abstract

Diaphania hyalinata (L.) is the most important melon pest in Colombia due to its economic damage and to the high population, it reaches, which means high insecticide usage. A study was carried out to determine the life cycle, foliage consumption, and fruit damage, at "Cari­bia" an ICA Experiment Station, located in Sevilla-Ciénaga (Magdalena, Colombia) with an average temperature of 26,8°C and 84% of relative humidity. The experiments were con­ducted both under insectary and field conditions. In order to conduct these studies, female insects were captured by using light traps and then placed in 1-gallon capacity glass jars for oviposition. For the life cycle and foliage consumption determinations, a sample of 50 worms was placed individually in Petri dishes; for the fruit damage evaluation, the insect preference for large or small fruits was recorded in a completely randomized design with six replicates. The larvae were placed in cages over the fruits and every day the damage and the instar changes were recorded. The egg fertility was 98.4± 1.5% with an incubation period of 3,0* 1.0 days; the larva showed five instars with a total duration of 12.3* 0.6 days; the pre-pupa lasted 2.0± 0.2 days, and the pupa stage 7.8± 0.4 days; the total duration from egg to pupa was 23.2± 0.85 days, in the average. The foliage consumption during all the larval development was 40.58 cm²; there were no significant differences between fruit size in relation to fruit damage. The first instar larvae did not feed on the fruits and starved to death and were only able to feed on the fruits the 5th instar, which perforated the rind and consumed the flesh, permitting posterior rot and Loss of the fruits.