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

Abstract

Over the past three decades, highly increased whitefly (Bemisia tabaci) 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 Bemisia tabaci species complex known to infest cassava crops in Africa. This study carried out an in-depth survey to understand the distribution of B. tabaci 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 mitochondrial cytochrome oxidase 1 sequences (651 bp) in the 3′ barcode region used for B. tabaci systematics. Sixteen B. tabaci and five related whitefly putative species were identified based on > 4.0% nucleotide divergence, of which three are proposed as novel B. tabaci putative species and four as novel closely related whitefly species. The most prevalent whiteflies were classified as B. tabaci 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 (Sida acuta and Ocimum gratissimum). 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.

A Review on Transcriptional Responses of Interactions between Insect Vectors and Plant Viruses

“…The geographical distribution of aphids tends to be predominantly in temperate regions, and aphids are major pests of crops such as cereals including wheat and barley [ 21 , 22 ]. Whiteflies are known to be prevalent in sub-tropical and tropical regions and certain members in the cryptic species complex are pests on a variety of vegetable and row crops such as cotton [ 23 , 24 ]. Leaf and planthoppers are pests of host plants such as potato, rice, and soybean in temperate, sub-tropical, and tropical regions of the world [ 25 , 26 ].…”

Lysine provisioning by horizontally acquired genes promotes mutual dependence between whitefly and two intracellular symbionts

“…The whitefly Bemisia tabaci is a complex of more than 40 cryptic species as revealed by phylogenetic analyses and mating experiments [17,18]. B. tabaci MEAM1 is one of the most important and invasive pests of agriculture [19,20].…”

“…The whitefly Bemisia tabaci is a complex of more than 40 cryptic species as revealed by phylogenetic analyses and mating experiments [ 17 , 18 ]. B .…”

Population Genetic Structure of the Bean Leaf Beetle <em>Ootheca mutabilis</em> (Coleoptera: Chrysomelidae) in Uganda

“…Currently, the only reliable morphological identification method is through dissection and examination of the male genitalia [26], a method that excludes the species-level identification of females and other growth stages. Therefore, there is a need to use molecular diagnostic methods, with the use of partial mitochondrial DNA cytochrome c oxidase subunit I (mtCOI) sequences being a favoured method globally and that has been used successfully in our Ugandan laboratories for other agricultural pests (for example, [39,38,36]. The spatial population genetic structure of O. mutabilis has not been determined.…”