Browsing by Author "Macfadyen, Sarina"

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    Influence of Cassava Morphological Traits and Environmental Conditions on Field Populations of Bemisia tabaci
    (Insects, 2021) Katono, Kasifa; Macfadyen, Sarina; Omongo, Christopher Abu; Lapaka Odong, Thomas; Colvin, John; Karungi, Jeninah; Otim, Michael Hilary
    High populations of species in the whitefly complex Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) were reported to cause severe damage to cassava in East and Central Africa. However, reasons for B. tabaci population increases are not well understood. We investigated the effect of cassava morphological traits, temperature, rainfall and relative humidity (RH) on the abundance of B. tabaci. Five cassava genotypes with varying levels of resistance to cassava mosaic disease, cassava brown streak disease, and B. tabaci infestation were planted in three Ugandan agro-ecological zones. The experiment was conducted in 2016 and 2017 in a randomized complete block design. Across all locations, the tallest genotype Alado alado supported the lowest number of B. tabaci adults. In areas with high B. tabaci prevalence, leaf area, leaf lobe width, and leaf lobe number exhibited significant positive effects (p < 0.001) on B. tabaci adult count. Positive effects of relative humidity and negative effects of temperature and rainfall on B. tabaci adult and nymph counts were observed in 2016 and 2017, resulting in low populations in Lira. Evidently, temperatures of 28–30 C, rainfall of 30–150 mm and RH of 55–70%, and deployment of cassava genotypes of low plant height, large leaf area, and lobe width significantly enhanced B. tabaci population growth.
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    Review and guide to a future naming system of African Bemisia tabaci species
    (Systematic Entomology, 2018) Boykin, Laura M .; Kinene, Tonny; Wainaina, James M.; Derssavill, A. N.; Seal, Susan; Mugerwa, Habibu; Macfadyen, Sarina; Tek Tay, Wee; De Barro, Paul; Kubatko, Laura; Alicai, Titus; Omongo, Christopher A .; Tairo, Fred; Ndunguru, Joseph; Sseruwagi, Peter
    Once a pest has been correctly identified, its genus and species name can provide a link to valuable indications of its ecology, biology and life history that are critical for developing control strategies. Importantly, this link should exist even when the pest was known under other names (synonyms), or was not considered a pest at all (National Research Council, 1968). Many examples have shown that incorrect identification or classification of a pest has led to fruitless searches for biocontrol agents in the native range, incorrect assignments as disease vectors, and costly, yet misdirected, suppression measures. As new approaches for delimiting species based on molecular information become more widely used, the process of correctly identifying a species has become even more complex. Fortunately, we have good systematic frameworks and nomenclatural systems that are able to cope with these challenges. Here we review challenges associated with classification and identificationwithin the Bemisia tabaci (Gennadius) species complex.