Population of predacious phytoseiid mites, Euseius kenyae (Swirski and Ragusa) on coffee treated with different soil applied fertilizers
Predacious phytoseiid mites, Euseius kenyae (Swirski and Ragusa) plays a major role in management of coffee thrips and other pests such as Phytophygous mites in coffee. Their conservation under various agro-ecosystems remains importance. An assessment on effect of organic and inorganic fertilizer sources on augmentation and conservation of E. kenyae was carried out at Coffee Research Station (CRS), Ruiru. Compound organic and inorganic fertilizers were applied on mature coffee trees as the treatments. There were no biocides sprayed to control the coffee pests. The population of E. kenyae was assessed monthly. Fertilizers significantly increased the number of E. kenyae. The mites' population initially increased and thereafter leveled out. The population of E. kenyae was increased by 2.3, 1.8 and 1.3 folds under organic compost, N.P.K. 22:6:12 and N.P.K. 17:17:17 respectively when compared with control. Temperature and rainfall fluctuations affected the population of E. kenyae either positively or negatively. To enhance conservation of E. kenyae under coffee growing agro-ecosystems, farmers are encouraged to use organic manure. This will benefit the management of coffee thrips and other insect pests as well as the conservation of environment.