Temporal distribution of cocoa mirid species (Hemiptera: Miridae) in the Eastern, Ashanti and Volta regions of Ghana

Cocoa, Theobroma cacao L. is an important cash crop in Ghana and elsewhere in West Africa. It contributed to about 28% of Ghana’s foreign exchange earnings and 63% of the foreign export earnings from the agricultural sector in 2005. Cocoa production is plagued with several constraints including insects pest (e.g. mirids) and diseases (e.g. black pod disease). There are four mirid species in West Africa; the dominant species of economic importance in Ghana are Distantiella theobroma (Distant) and   Sahlbergella singularis Haglund. Earlier records focused on D. theobroma as the dominant species in Ghana. Subsequently, there has been a switch from D. theobroma to S. singularis. The present study aimed at determining the distribution of the two mirid species in cocoa producing areas of the Eastern, Ashanti and Volta regions of Ghana. Mirids were sampled from various cocoa farms using the visual hand-height assessment method.  Both species were present in all three regions with Volta Region recording the lowest percentage of 10, but the dominant species in the three regions was S. Singularis with the S. singularis to D. theobroma ratio of 8.6:1.4.