Preliminary study on nutmeg damage by trunk borer at Minahasa, North Sulawesi (Indonesia)
1991
Munaan, A.
A study to find out nutmeg loss due to trunk borer, Batocera hercules Boisd was conducted at Air Madidi and Kauditan in North Sulawesi in 1990. The borer selected large trunks of 30 cm or more diameter. The numbers of entry holes reached 34 per trunk while the maximum numbers of exit holes were nine. Most of the entry and exit holes were located around 0.5-2 m above the ground level. The holes were very close to each other and so were the infested trees, showing that the pest distribution was patchy. Brown exudate oozed from the cut made by young larvae on the bark. This represents a symptom of the infestation at early stage and can be used for monitoring in the context of controlling the pest. The crown of infested trees were severely damaged while the nut numbers reduced to 24 percent and every infested tree was eventually killed. The percentage of infested big trees was 17 percent at Air Madidi and 26 percent at Kauditan. Empty spaces with some nutmeg stamps were found in the gardens, suggesting the loss was due to B. hercules.
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