Genetic diversity of whitefly ( spp.) on crop and uncultivated plants in Uganda: implications for the control of this devastating pest species complex in Africa.

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Over the past three decades, highly increased whitefly () populations have been observed on the staple food crop cassava in eastern Africa and associated with ensuing viral disease pandemics and food insecurity. Increased whitefly numbers have also been observed in other key agricultural crops and weeds. Factors behind the population surges on different crops and their interrelationships are unclear, although in cassava they have been associated with specific populations within the species complex known to infest cassava crops in Africa. This study carried out an in-depth survey to understand the distribution of populations infesting crops and uncultivated plant hosts in Uganda, a centre of origin for this pest complex. Whitefly samples were collected from 59 identified plant species and 25 unidentified weeds in a countrywide survey. Identities of 870 individual adult whiteflies were determined through sequences (651 bp) in the 3' barcode region used for systematics. Sixteen and five related whitefly putative species were identified based on > 4.0% nucleotide divergence, of which three are proposed as novel putative species and four as novel closely related whitefly species. The most prevalent whiteflies were classified as MED-ASL (30.5% of samples), sub-Saharan Africa 1 (SSA1, 22.7%) and Bemisia Uganda1 (12.1%). These species were also indicated to be the most polyphagous occurring on 33, 40 and 25 identified plant species, respectively. Multiple (≥ 3) whitefly species occurred on specific crops (bean, eggplant, pumpkin and tomato) and weeds ( and ). These plants may have increased potential to act as reservoirs for mixed infections of whitefly-vectored viruses. Management of whitefly pest populations in eastern Africa will require an integration of approaches that consider their degree of polyphagy and a climate that enables the continuous presence of crop and uncultivated plant hosts.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10340-021-01355-6.