Abstract

Sammie Van, Melfah Nanaba and Tadias Kwame

The influence of six levels of fertilizer on the nitrogen content of coffee berries and the resulting incidence of Hypothenemus hampei was investigated on three improved clones of Robusta coffee at the Afosu Sub-station of the Cocoa Research Institute of Ghana. The treatments were unfertilized control, basal dressing of 100 kg P2O5 ha-1 mixed with 100 kg K 2O ha-1 , basal dressing of 100 kg P2O5 ha-1 with 100 kg K2O ha-1 and 50 kg N ha-1 , basal dressing of 100 kg P2O 5 ha-1 with 100 kg K2O ha-1 and 70 kg N ha-1 , basal dressing of 100 kg P2O 5 ha-1 with 100 kg K2O ha-1 and 90 kg N ha-1 , as well as basal dressing of 100 kg P2O5 ha-1 with 100 kg K2O ha-1 and 150 kg N ha-1 . The coffee clones were E152, E139 and E138. No differences were found in the nitrogen contents of berries of the various clones. Application of higher rates of fertilizer to the soil increased the nitrogen content and H. hampei numbers in the berries. The correlation coefficients between fertilizer dose and H. hampei numbers were significant. The relation between nitrogen in the berries and H. hampei numbers was also significant.