scholarly journals 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

2021 ◽  
Author(s):  
Habibu Mugerwa ◽  
John Colvin ◽  
Titus Alicai ◽  
Christopher A. Omongo ◽  
Richard Kabaalu ◽  
...  
Keyword(s):  
Plant Species ◽  
Bemisia Tabaci ◽  
Species Complex ◽  
Viral Disease ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
Pest Species ◽  
Sida Acuta ◽  
Putative Species ◽  
Plant Hosts

AbstractOver 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.

scholarly journals The potential geographical distribution and phenology of Bemisia tabaci Middle East/Asia Minor 1, considering irrigation and glasshouse production

2020 ◽  
Vol 110 (5) ◽  
pp. 567-576 ◽  
Author(s):  
D. J. Kriticos ◽  
P. J. De Barro ◽  
T. Yonow ◽  
N. Ota ◽  
R. W. Sutherst
Keyword(s):  
Middle East ◽  
East Asia ◽  
Open Field ◽  
Bemisia Tabaci ◽  
Species Complex ◽  
Potential Distribution ◽  
Invasive Pest ◽  
Asia Minor ◽  
Potential Range ◽  
Pest Species

AbstractThe Bemisia tabaci species complex is one of the most important pests of open field and protected cropping globally. Within this complex, one species (Middle East Asia Minor 1, B. tabaci MEAM1, formerly biotype B) has been especially problematic, invading widely and spreading a large variety of plant pathogens, and developing broad spectrum pesticide resistance. Here, we fit a CLIMEX model to the distribution records of B. tabaci MEAM1, using experimental observations to calibrate its temperature responses. In fitting the model, we consider the effects of irrigation and glasshouses in extending its potential range. The validated niche model estimates its potential distribution as being considerably broader than its present known distribution, especially in the Americas, Africa and Asia. The potential distribution of the fitted model encompasses the known distribution of B. tabaci sensu lato, highlighting the magnitude of the threat posed globally by this invasive pest species complex and the viruses it vectors to open field and protected agriculture.

Reproductive incompatibility among genetic groups of Bemisia tabaci supports the proposition that the whitefly is a cryptic species complex

2010 ◽  
Vol 100 (3) ◽  
pp. 359-366 ◽  
Author(s):  
J. Xu ◽  
P.J. De Barro ◽  
S.S. Liu
Keyword(s):  
Cryptic Species ◽  
Bemisia Tabaci ◽  
Species Complex ◽  
Phylogenetic Analyses ◽  
Strong Support ◽  
Crossing Experiments ◽  
Complex Species ◽  
Putative Species ◽  
Reproductive Incompatibility ◽  
Cryptic Species Complex

AbstractThe worldwide distribution and extensive genetic diversity of the whitefly Bemisia tabaci has long been recognized. However, whether B. tabaci is a complex species or a species complex has been a subject of debate. Recent phylogenetic analyses suggest that B. tabaci is a cryptic species complex composed of at least 24 morphologically indistinguishable species. Here, we conducted crossing experiments and demonstrated reproductive incompatibility among three of the 24 putative species. Our data and those of previously reported crossing experiments among various putative species of B. tabaci were collated to reveal the pattern of reproductive isolation. The combined results provide strong support to the proposition that B. tabaci is a cryptic species complex.

scholarly journals Updated status of whiteflies (Hemiptera: Aleyrodidae) in Jordan with emphasis on the Bemisia tabaci species complex

2021 ◽  
Vol 47 (1) ◽  
pp. 1-9
Author(s):  
Ihab Ghabeish ◽  
Mais Sweiss ◽  
Ghandi Anfoka
Keyword(s):  
Bemisia Tabaci ◽  
Species Complex ◽  
Diagnostic Techniques ◽  
Morphological Identification ◽  
Special Focus ◽  
Plant Pests ◽  
Putative Species ◽  
Geographical Regions ◽  
The Status ◽  
Mtcoi Gene

Whiteflies are economically important plant pests that cause damage to crops worldwide. This study aimed to update the status of whiteflies in Jordan by combining the classical morphological identification and the DNA markers using the mitochondrial cytochrome oxidase I (mtCOI) gene. Over the course of three consecutive years, 111 whiteflies were collected from different geographical regions and different plant hosts in Jordan. The results showed that, in addition to Bemisia tabaci, another nine different whitefly species were identified, including two species that were recorded for the first time in Jordan: Africaleurodes coffeacola, and Tetraleurodes neemani. A special focus has been given to economically important plant pests like the B. tabaci species complex. Three different diagnostic techniques were used to identify B. tabaci putative species based on mtCOI gene. All the collected samples of B. tabaci species complex were identified as Middle East–Asia Minor 1 (MEAM1) putative species.

Impact of crop cycle on movement patterns of pest rodent species between fields and houses in Africa

2011 ◽  
Vol 38 (7) ◽  
pp. 603 ◽  
Author(s):  
Ara Monadjem ◽  
Themb'a A. Mahlaba ◽  
Nomfundo Dlamini ◽  
Seth J. Eiseb ◽  
Steven R. Belmain ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Crop Production ◽  
Radio Telemetry ◽  
Sub Saharan Africa ◽  
Rodent Species ◽  
Eastern Africa ◽  
Pest Species ◽  
Natural Habitats ◽  
Post Harvest ◽  
Field Rodents

Context Rodent pests can have severe impacts on crop production in sub-Saharan Africa. In particular, the multimammate mouse Mastomys natalensis severely damages agricultural crops in southern and eastern Africa, leading to significant losses. Both its population ecology and breeding biology have been studied in agricultural and natural habitats. Population numbers erupt depending on the timing and amount of rainfall and may reach plague proportions, especially in agricultural settings, where it may become a serious pest. However, the ecology of this species, in particular its interactions with other species within the context of human settlement, is poorly understood. It may occasionally enter houses, but the degree to which it does so and the factors influencing this movement are not known. Aims We investigated the relationship between Rattus spp. and M. natalensis entering buildings in an agro-ecological setting. We predicted that M. natalensis would enter houses more readily when food availability was lowest in the surrounding fields, and when the larger Rattus spp. were absent. Methods We followed 40 individuals of M. natalensis in Swaziland and Namibia by radio-telemetry. Mice were captured in maize fields within 50 m of a homestead and fitted with radio-transmitters at three different times corresponding to different stages of crop development: pre-harvest, post-harvest and pre-planting. To corroborate the findings of the telemetry study, a non-toxic marker, rhodamine B, was mixed with standard bait and left at bait stations inside houses in 10 homesteads in Swaziland and Tanzania. Key results Mice remained in the fields during the entire period of study in Swaziland, but entered buildings in Namibia during the post-harvest stage, which may represent a period of food shortage for these mice in the field. Rodents captured after baiting with rhodamine B demonstrated that Rattus spp. predominated within the houses. A small number of rhodamine B-marked M. natalensis were captured outside the houses, the proportion declining with distance away from the houses. Conclusions These results suggest that in a typical rural African setting dominated by subsistence agriculture, Rattus spp. (when present) competitively exclude the smaller M. natalensis from entering houses. Implications Interactions between rodent pest species may be important in determining which rodent species enter houses in rural African landscapes. Consideration of such interactions may play an important role when developing pest management strategies.

scholarly journals Bemisia tabaci Vesicle-Associated Membrane Protein 2 Interacts with Begomoviruses and Plays a Role in Virus Acquisition

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1700
Author(s):  
Yun-Yun Fan ◽  
Yu-Wei Zhong ◽  
Jing Zhao ◽  
Yao Chi ◽  
Sophie Bouvaine ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Bemisia Tabaci ◽  
Species Complex ◽  
Molecular Mechanisms ◽  
Whole Body ◽  
Sri Lankan ◽  
Tomato Production ◽  
Virus Acquisition ◽  
Leaf Curl Virus ◽  
Whitefly Vector

Begomoviruses cause substantial losses to agricultural production, especially in tropical and subtropical regions, and are exclusively transmitted by members of the whitefly Bemisia tabaci species complex. However, the molecular mechanisms underlying the transmission of begomoviruses by their whitefly vector are not clear. In this study, we found that B. tabaci vesicle-associated membrane protein 2 (BtVAMP2) interacts with the coat protein (CP) of tomato yellow leaf curl virus (TYLCV), an emergent begomovirus that seriously impacts tomato production globally. After infection with TYLCV, the transcription of BtVAMP2 was increased. When the BtVAMP2 protein was blocked by feeding with a specific BtVAMP2 antibody, the quantity of TYLCV in B. tabaci whole body was significantly reduced. BtVAMP2 was found to be conserved among the B. tabaci species complex and also interacts with the CP of Sri Lankan cassava mosaic virus (SLCMV). When feeding with BtVAMP2 antibody, the acquisition quantity of SLCMV in whitefly whole body was also decreased significantly. Overall, our results demonstrate that BtVAMP2 interacts with the CP of begomoviruses and promotes their acquisition by whitefly.

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

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 260
Author(s):  
Habibu Mugerwa ◽  
Peter Sseruwagi ◽  
John Colvin ◽  
Susan Seal
Keyword(s):  
Food Security ◽  
Bemisia Tabaci ◽  
Development Time ◽  
Adult Emergence ◽  
Sub Saharan Africa ◽  
Biological Traits ◽  
Population Development ◽  
Species Classification ◽  
First Instar ◽  
Sub Saharan

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.

scholarly journals Within-Season Changes in Land-Use Impact Pest Abundance in Smallholder African Cassava Production Systems

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 269 ◽  
Author(s):  
Andrew Kalyebi ◽  
Sarina Macfadyen ◽  
Andrew Hulthen ◽  
Patrick Ocitti ◽  
Frances Jacomb ◽  
...  
Keyword(s):  
Land Use ◽  
Bemisia Tabaci ◽  
Large Scale ◽  
Production Systems ◽  
Smallholder Farmers ◽  
Negative Relationship ◽  
Central Africa ◽  
Sub Saharan Africa ◽  
Smallholder Farming ◽  
Manihot Esculenta Crantz

Cassava (Manihot esculenta Crantz), an important commercial and food security crop in East and Central Africa, continues to be adversely affected by the whitefly Bemisia tabaci. In Uganda, changes in smallholder farming landscapes due to crop rotations can impact pest populations but how these changes affect pest outbreak risk is unknown. We investigated how seasonal changes in land-use have affected B. tabaci population dynamics and its parasitoids. We used a large-scale field experiment to standardize the focal field in terms of cassava age and cultivar, then measured how Bemisia populations responded to surrounding land-use change. Bemisia tabaci Sub-Saharan Africa 1 (SSA1) was identified using molecular diagnostics as the most prevalent species and the same species was also found on surrounding soybean, groundnut, and sesame crops. We found that an increase in the area of cassava in the 3–7-month age range in the landscape resulted in an increase in the abundance of the B. tabaci SSA1 on cassava. There was a negative relationship between the extent of non-crop vegetation in the landscape and parasitism of nymphs suggesting that these parasitoids do not rely on resources in the non-crop patches. The highest abundance of B. tabaci SSA1 nymphs in cassava fields occurred at times when landscapes had large areas of weeds, low to moderate areas of maize, and low areas of banana. Our results can guide the development of land-use strategies that smallholder farmers can employ to manage these pests.

scholarly journals Assortments of Digestive Enzymes Induced in First Instar Larvae of Busseola fusca Feeding on Different Plants

2019 ◽  
Vol 11 ◽  
pp. 117954331984352 ◽  
Author(s):  
Gérald Juma ◽  
Bruno Le Ru ◽  
Paul-André Calatayud
Keyword(s):  
Plant Species ◽  
Digestive Enzymes ◽  
Host Plants ◽  
Feeding Habits ◽  
Busseola Fusca ◽  
Stem Borer ◽  
Sub Saharan Africa ◽  
Host Acceptance ◽  
First Instar ◽  
Sub Saharan

The stem borer Busseola fusca (Fuller) (Lepidoptera: Noctuidae) is an important pest of maize and sorghum in sub-Saharan Africa. This insect has oligophagous feeding habits, feeding mostly on maize and sorghum with a narrow range of wild Poaceous plant species. We hypothesised that first instar B. fusca larvae, the critical stage for successful establishment on a host plant, can establish and then grow on a particular plant as a result of induction of a complement of digestive enzymes that mediates host acceptance at first instars. A fast semi-quantitative analysis of potentially digestive enzymatic activities present in the first larvae previously fed for 4 days on leaves of host and non-host plants was performed using the API-ZYM kit system able to detect a multiplex of enzyme activities. Regardless of the plant species, the larvae exhibited higher activities of the carbohydrate metabolising enzymes than of aminopeptidases and proteases. In addition, highest activities of carbohydrates degrading enzymes were exhibited by larvae that consumed leaves of the most preferred plant species of B. fusca. Conversely, esterases were only detected in neonate larvae that consumed leaves of the less preferred and non-host plants. No alkaline phosphatase and lipase activities were detected. The significance of these results was discussed in terms of food requirements of first instar larvae when settling on a plant.

Responses of insect pests, pathogens, and invasive plant species to climate change in the forests of northeastern North America: What can we predict?This article is one of a selection of papers from NE Forests 2100: A Synthesis of Climate Change Impacts on Forests of the Northeastern US and Eastern Canada.

2009 ◽  
Vol 39 (2) ◽  
pp. 231-248 ◽  
Author(s):  
Jeffrey S. Dukes ◽  
Jennifer Pontius ◽  
David Orwig ◽  
Jeffrey R. Garnas ◽  
Vikki L. Rodgers ◽  
...  
Keyword(s):  
Climate Change ◽  
Plant Species ◽  
Invasive Plant ◽  
Insect Pests ◽  
Adelges Tsugae ◽  
Pest Species ◽  
Invasive Plant Species ◽  
Eastern Canada ◽  
Wide Range ◽  
Nuisance Species

Climate models project that by 2100, the northeastern US and eastern Canada will warm by approximately 3–5 °C, with increased winter precipitation. These changes will affect trees directly and also indirectly through effects on “nuisance” species, such as insect pests, pathogens, and invasive plants. We review how basic ecological principles can be used to predict nuisance species’ responses to climate change and how this is likely to impact northeastern forests. We then examine in detail the potential responses of two pest species (hemlock woolly adelgid ( Adelges tsugae Annand) and forest tent caterpillar ( Malacosoma disstria Hubner)), two pathogens (armillaria root rot ( Armillaria spp.) and beech bark disease ( Cryptococcus fagisuga Lind. + Neonectria spp.)), and two invasive plant species (glossy buckthorn ( Frangula alnus Mill.) and oriental bittersweet ( Celastrus orbiculatus Thunb.)). Several of these species are likely to have stronger or more widespread effects on forest composition and structure under the projected climate. However, uncertainty pervades our predictions because we lack adequate data on the species and because some species depend on complex, incompletely understood, unstable relationships. While targeted research will increase our confidence in making predictions, some uncertainty will always persist. Therefore, we encourage policies that allow for this uncertainty by considering a wide range of possible scenarios.

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