Genetic Diversity of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Colonizing Sweet Potato and Cassava in South Sudan

Misaka, Beatrice C; Wosula, Everlyne N.; Marchelo-d’Ragga, Philip W.; Hvoslef-Eide, Trine; Legg, J.P.

doi:10.3390/insects11010058

Cited by 20 publications

(19 citation statements)

References 89 publications

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“…pumpkin (55/70 pumpkin whiteflies), sweet potato (38/79) and tomato (14/51) but not at all to cassava (0/98). The strong association with sweet potato in the field has been noted previously (Sseruwagi et al 2006;Misaka et al 2019), and recent studies have verified that sweet potato is a preferred host for MED-ASL under laboratory as well as field conditions (Vyskočilová et al 2019;Macfadyen et al 2020). These data support the proposal of Vyskočilová et al (2018Vyskočilová et al ( , 2019 to classify MED-ASL as a distinct species from MED-Q1, due to these populations failing to interbreed, showing a distinct mtCO1 phylogenetic placement, as well as marked differences in their preferred host ranges.…”

Section: Abundance and Host Range Of Whitefly Speciessupporting

confidence: 75%

“…4). MacFadyen et al (2020) also found SSA2 to be present in only a few regions of central to northern Uganda, and in neighbouring South Sudan, SSA2 was reported recently as the most prevalent (Misaka et al 2019) adding weight to the prevalence and locality of SSA2 being linked to agroecology and landscape factors rather than a chance event caused by the timing of our survey. SSA1(-SG1) is prevalent across the rest of Uganda and this is considered linked to its ability to feed on and colonise multiple host plants including cassava (Sseruwagi et al 2006;Milenovic et al 2019).…”

Section: Geographical Distribution Of Prevalent Whitefly Speciessupporting

confidence: 52%

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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

et al. 2021

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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.

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Section: Abundance and Host Range Of Whitefly Speciessupporting

confidence: 75%

Section: Geographical Distribution Of Prevalent Whitefly Speciessupporting

confidence: 52%

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

et al. 2021

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“…2). Some studies suggest that B. tabaci IO does not use cassava as a host plant (Misaka et al 2020), however nymphs of this species were recorded on cassava and other plants throughout our study. B. tabaci SSA1 was also recorded on other crop and non-crop plants (e.g., wild groundnut, sweet potato), but often not in the frequency with which it was recorded on cassava (Fig.…”

Section: What Are the Common Species Of Whitefly Found On Cassava And On Nearby Crops And Non-crop Host Plants?contrasting

confidence: 67%

“…In Tanzania, the B. tabaci IO species was also relatively common in some cassava fields, on cassava plants. Misaka et al (2020) did not record B. tabaci IO on cassava in a survey conducted in South Sudan, however, their study focussed on collecting adults and sequenced low numbers of individuals from cassava. In our study, B. tabaci SSA2 was found relatively frequently but in low density on other crop plants and non-crop plants in cassava production landscapes (Fig.…”

Section: Discussionmentioning

confidence: 99%

Landscape factors and how they influence whitefly pests in cassava fields across East Africa

et al. 2020

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Context African production landscapes are diverse, with multiple cassava cultivars grown in small patches amongst a diversity of other crops. Studies on how diverse smallholder landscapes impact herbivore pest outbreak risk have not been carried out in sub-Saharan Africa. Objectives Bemisia tabaci is a cryptic pest species complex that cause damage to cassava through feeding and vectoring plant-virus diseases and are known to reach very high densities in certain contexts. However, the factors driving this phenomenon are unclear. Methods Bemisia density data in cassava across a large number of sites representing a geographic gradient across Uganda, Tanzania and Malawi were collected. We tested whether in-field or landscape factors associated with land-use patterns underpinned Bemisia density variability and parasitism. Results We found the B. tabaci SSA1 species dominated our study sites, although other species were also common in some cassava fields. Factors associated with the surrounding landscape were unimportant for explaining variability in adult density, but the in-field variables of cassava age and cultivar were very important. The density of nymphs and the parasitism of nymphs was heavily influenced by a diversity of landscape factors surrounding the field, including the size of focal cassava field, and area of cassava in the landscape. However, unlike the trend from many other studies on drivers of natural enemy populations, this pattern was not solely related to the amount of non-crop vegetation, or the diversity of crops grown in the landscape. Conclusions Our findings provide management options to reduce whitefly abundance, including describing the characteristics of landscapes with high parasitism. The choice of cassava cultivar by the farmer is critical to reduce whitefly outbreak risk at the landscape-scale.

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“…SSA2 B. tabaci whitefly possessed similar biological traits with SSA1-SG1 B. tabaci whitefly in the insectary, which corroborates field reports of high whitefly abundance associated with the two species in East Africa [ 4 , 19 , 22 , 23 ]. A few studies reported SSA2 whiteflies as the highly abundant whitefly species on cassava in Uganda (between 1997 to 1999) [ 11 ], in some areas of northern Uganda [ 22 , 23 ] and in Juba, South Sudan [ 49 ]. The study indicated SSA2 B. tabaci whitefly to have a slightly higher proportion of emerged female adults.…”

Section: Discussionmentioning

confidence: 99%

Is High Whitefly Abundance on Cassava in Sub-Saharan Africa Driven by Biological Traits of a Specific, Cryptic Bemisia tabaci Species?

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Sseruwagi

Colvin

et al. 2021

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In East Africa, the prevalent Bemisia tabaci whiteflies on the food security crop cassava are classified as sub-Saharan Africa (SSA) species. Economically damaging cassava whitefly populations were associated with the SSA2 species in the 1990s, but more recently, it has been to SSA1 species. To investigate whether biological traits (number of first instar nymphs, emerged adults, proportion of females in progeny and development time) of the cassava whitefly species are significant drivers of the observed field abundance, our study determined the development of SSA1 sub-group (SG) 1 (5 populations), SG2 (5 populations), SG3 (1 population) and SSA2 (1 population) on cassava and eggplant under laboratory conditions. SSA1-(SG1-SG2) and SSA2 populations’ development traits were similar. Regardless of the host plant, SSA1-SG2 populations had the highest number of first instar nymphs (60.6 ± 3.4) and emerged adults (50.9 ± 3.6), followed by SSA1-SG1 (55.5 ± 3.2 and 44.6 ± 3.3), SSA2 (45.8 ± 5.7 and 32.6 ± 5.1) and the lowest were SSA1-SG3 (34.2 ± 6.1 and 32.0 ± 7.1) populations. SSA1-SG3 population had the shortest egg–adult emergence development time (26.7 days), followed by SSA1-SG1 (29.1 days), SSA1-SG2 (29.6 days) and SSA2 (32.2 days). Regardless of the whitefly population, development time was significantly shorter on eggplant (25.1 ± 0.9 days) than cassava (34.6 ± 1.0 days). These results support that SSA1-(SG1-SG2) and SSA2 B. tabaci can become highly abundant on cassava, with their species classification alone not correlating with observed abundance and prevalence.

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Genetic Diversity of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Colonizing Sweet Potato and Cassava in South Sudan

Cited by 20 publications

References 89 publications

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

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

Landscape factors and how they influence whitefly pests in cassava fields across East Africa

Is High Whitefly Abundance on Cassava in Sub-Saharan Africa Driven by Biological Traits of a Specific, Cryptic Bemisia tabaci Species?

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