Establishment Of The Biological Control System By Black Ant, Dolichoderus Thoracicus (Smith) (Hymenoptera: Formicidae) And Mealybug, Cataenococcus Hispidus (Morrison) (Homoptera: Pseudococcidae) Against The Cocoa Pod Borer, Conopomorpha Cramerella (Snellen) (Lepidoptera: Gracillariidae) In North Sumatera, Indonesia
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Date
2011-07
Authors
Saleh, Ahmad
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
A study on the establishment of Dolichoderus thoracicus (black ant) and
Cataenococcus hispidus (mealybug) to be used as biological agents for Conopomorpha
cramerella, cocoa pod borer (CPB) was carried out in LONSUM cocoa estates in Bah
Lias, North Sumatera. Conopomorpha cramerella moths prefer to lay their eggs on
cocoa pods stage 4 (age 13 – 16 weeks old; 15 to 20 cm length). High population of
eggs and larvae were found in the beginning and the end of the year or after the end of
cocoa peak crop. Most of the eggs and the larvae on pods were found from upper
canopy, less on pods from lower canopy and lowest on pods from the trunk. The highest
number of entry and exit holes of CPB larvae was on pods stage 5 (age 17 – 20 weeks
old; 15 to 20 cm length) while the exit holes were not found on pods stages 1 (age 1 – 4
weeks old; 1 to 4 cm length) and 2 (age 5 – 8 weeks old; 5 to 10 cm length). Seventy
percent of larvae exited from cocoa pods between 2100 - 0400 hr and the peak was at
0200 hr. In spite of this, 5 % of larvae emerged in the first day or less than 46 %
emerged from harvested pods within 3 days. Within less than one hour the emerging
larvae formed cocoons. Sixty seven eggs were laid by one female. Parasitized eggs were
not found on the examined pods, while 92 - 98 % natural mortality of larvae was
obseved in cocoa pods. In addition, the proportion of natural mortality of pupae was
higher on the ground compared to in the canopy. More than 30 % of the pupae collected
from the field were dead probably due to natural mortality.
Description
Keywords
Black Ant, Dolichoderus Thoracicus (Smith) (Hymenoptera: Formicidae) , Cocoa Pod Borer, Conopomorpha Cramerella (Snellen) (Lepidoptera: Gracillariidae)