PUPATION AND ADULT EMERGENCE OF THE COCOA POD BORER, Conopomorpha cramerella (SNELLEN) AFTER TREATED WITH DELTAMETHRIN AND CYPERMETHRIN INSECTICIDES
Authors: Saripah, B.
Journal Issue: Malaysian Cocoa Journal, Volume 14/2022
Keywords: Cocoa pod borer, cypermethrin, Conopomorpha cramerella, deltamethrin, pupation, adult emergence
Published On: 10/05/2022
Abstract
Insecticide application is still preferable by the Malaysian cocoa growers in managing Conopomorpha cramerella. Two commonly used insecticides, Deltamethrin and Cypermethrin, were tested at three concentrations (1%, 2%, and 4%), and a comparison was made with water as a control. Insecticides were sprayed on the cocoa pod surface, and the numbers of pupa emerged, and adult emergence was recorded. Ten cocoa pods were selected for each treatment, and the study was replicated three times. Observations on pupa emergence were carried out from Day-1 through Day-14. The percentage of pupa emergence was the highest at Days-7 and 10, and the least was observed at Day-13 (0.00%) and Day-12 (1.82%). The pupation period was shortest at control (4 days), and the longest was nine days at Cypermethrin 1%, Deltamethrin 1, and 2%. The early emergence of adults resulted in a lighter weight of C. cramerella where the shortest pupation period (4 days) was only 0.0014 ± 0.0003 b and significantly different with a more extended pupation period. Days 5 and 6 recorded heavier adults with 0.0027 ± 0.0005 a. Contrary to pupa weight, no significant difference in adult weight was obtained from both Deltamethrin and Cypermethrin. These results suggested that insecticide spraying on the cocoa pods shows no negative impact due to their cryptic behavior, which the larvae spend their entire life inside the pods. The cocoa pod's insecticide residue fewer influences pupation due to the tendency to pupate on a less treated area than the pod surface.