Efficiency of cassava brown streak virus transmission by two whitefly species in coastal Kenya

The efficiency of cassava brown streak virus (CBSV) transmission by Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and spiraling whitefly (Aleurodicus dispersus) Russell (Hom, Aleyrodidae) was determined. The transmission utilized field collected adult whitefly populations fed on (allowed 48 h acquisition access feeding period (AAP)) on CBSD (cassava brown streak virus disease) symptomatic leaves before transfer onto clean recipient plants. In subsequent transmission experiments, adult whitefly numbers of each species were varied per plant to determine the effect of whitefly numbers on the rate of CBSV transmission. CBSV was transmitted by B. tabaci allowed 48 h AAP on CBSD infected cassava leaves at a higher rate of 40.7% compared to that of A. dispersus at 25.9%. This work reports for the first time the transmission of CBSV by A. dispersus. A likely biological property of CBSV reported here for the first time is its ability to be transmitted by two whitefly species belonging to two different genera (Bemisia and Aleurodicus). Management of CBSD therefore needs to focus on the control of the two whitefly species to reduce the chances and rates of infection and disease spread.   Key words: Aleurodicus dispersus, Bemisia tabaci, CBSD, spiraling whitefly, transmission efficiency.