การควบคุมด้วงเมล็ดกาแฟด้วยวิธีการใช้คลื่นความถี่วิทยุ

Abstract

The coffee bean weevil, Araecerus fasciculatus (De Geer, 1775) (Coleoptera: Anthribidae), is an important insect pest of Arabica and Robusta coffee green bean during storage which caused unacceptable damage affected to coffee bean standards. In experiment 1, the radio frequency efficacy (RF) at 27.12 MHz was examined for controlling coffee bean weevil in Arabica green bean using 55 ºC for 90 seconds on the egg, larval, pupal and adult stages. The result showed that adult mortality was the least (46.43±1.82%) and significantly different (P<0.05) to those mortalities of egg (100%), larval (100%) and pupal (97.35±0.83%) stages, respectively. So, in adult stage, the coffee bean weevil was the most tolerant to RF heat treatment. In experiment 2, the combination of RF heat treatments at 55, 60, 65 and 70 ºC for 60, 90, 120 and 150 seconds (16 treatments) had treated on the adult of coffee bean weevil infested on green bean. No RF treatment was set as the untreated control in each stage. The result revealed that adults exposed to 70 ºC for 60 seconds caused 100% mortality and there was no progeny production. On the treatment with RF at 60 ºC for 150 seconds and at 65 and 70 ºC for 60, 90, 120 and 150 seconds, the survived adults exposed to RF heat treatments could not produce their progeny production. In experiment 3, the quality of green bean treated by RF treatment at 70 ºC for 60 seconds was examined. The moisture content was decreased from 16.50% to 16.10% (P<0.05). Direct plating method was used to detect postharvest fungi associated with green bean coffee compared between the before and after exposing treatments. Aspergillus niger was found for 7.5 % on green bean while there was no fungus after RF exposing.