Collection of test plant material.
The bark and stem of fresh mature Grevillea robusta were collected from Luanda Sub-county of Vihiga County. The stem was dried at 60°C in a shade for 72 h. The resulting dried sample was ground using a mill (Jehmlich, Germany) and placed in bags and transported to the National museums of Kenya for further experiments. The same procedure was repeated for Eucalyptus Sugarcane, Maize, Bamboo, and Cypress.