Managing whitefly development to control cassava brown streak virus coinfections

Abstract

Mixed infections of Cassava brown streak virus (CBSV) and its Ugandan variant (UCBSV) in cassava hosts are increasingly threatening food security in East and Central Africa. The possibility of these viruses spreading to cassava producing countries in West Africa is of great concern. Most epidemiological models developed to address this challenge do not include the possibility of coinfection and whitefly lifecycle in managing these viruses. The question is: how does the inclusion of whitefly lifecycle and temperature variability influence disease outbreak and spread? We develop a host-vector-virus coinfection model that incorporates the whitefly life cycle and temperature variability as drivers of an epidemic. Using a combination of analytical and numerical simulations, we identify the key factors that drive disease outbreaks in cassava plantations. We also demonstrate that management of the whitefly's immature development stage can reduce disease prevalence and crop losses associated with these outbreaks. These results suggest that biological control agents using natural enemies should be given higher priority than the use of insecticides in management strategies.