Outbreak, Distribution and Damage Characteristics of Cocoa Stem Borer, iEulophonotus myrmeleon/iFelder 1874 (Lepidoptera: Cossidae) in Major Cocoa Producing States in Nigeria

摘要

This study aims to ascertain the extent of the cocoa stem borer Eulophonotus myrmeleon distribution, outbreak, and damage to the cocoa plantations in six cocoa growing states in Nigeria. Three local government areas were selected from each of the six major cocoa states and three farms from each local government area. In each farm, 100 cocoa trees were randomly selected and inspected for symptoms and damages of E. myrmeleon. The result revealed that E. myrmeleon infestation has increased significantly (p = 0.01, df = 1, F = 41.77) in 2019 by 10% from the 2014 inspection. It also showed that the infestation level was significantly different from state to state. Symptoms of infestation include presence of entry/exit holes, woody exudates around the trees, yellowing and browning of the leaves. Damages caused by E. myrmeleon infestation are, loses of pod on the affected branch and tree and death of tree. Field observations showed clearly that stem borer is now becoming a serious problem and limiting considerably the production of cocoa in the region. It is time to give more attention to the biology and management of the pest. This is the first report detailing the symptoms and damage done by cocoa stem borers in Nigeria.