Bemisia tabaci (insect)

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General Impact 600 host plants have been cited in, Oliveira et al. (2001). Bemisia tabaci possibly originated in India (Fishpool & Burban, 1994) and as a result of widespread dispersal, particularly during the last 15 years, is now distributed nearly worldwide. B. tabaci is also a vector of over 100 plant viruses in the genera Begomovirus (Geminiviridae), Crinivirus (Closteroviridae) and Carlavirus or Ipomovirus (Potyviridae) (Jones, 2003). Damage is caused not only by direct feeding, but also through transmission of viruses. Begomoviruses are the most numerous of the B. tabaci transmitted viruses and can cause crop yield losses of between 20% and 100% (Brown & Bird, 1992). The EPPO (2004) states that, "Since the early 1980s, B. tabaci has caused escalating problems to both field and protected agricultural crops and ornamental plants. Heavy infestations of B. tabaci and B. argentifolii may reduce host vigour and growth, cause chlorosis and uneven ripening, and induce physiological disorders. The larvae produce honeydew on which sooty moulds grow, reducing the photosynthetic capabilities of the plant, resulting in defoliation and stunting. B. tabaci is known to be a potentially damaging pest of crops such as cotton, brassicas, cucurbits, okra, solanums in the tropics and subtropics (Goolsby et al. 2004). Ellsworth and Martinez-Carrillo (2001) state that, "B. tabaci’s small size belies its ability to move relatively large distances locally, placing many hosts within communities at risk of infestation. This ability to disperse is made worse by its extensive movement through commerce of plant products around the globe. The small size and rapid reproductive potential are other characteristics that result in explosive population growth. The damage potential of this pest as a direct plant stressor, virus vector, and quality reducer (e.g., by contamination with excreta) is substantial. These attributes, among others, render this species a shared pest within agricultural communities." Cassava mosaic disease (CMD) and cassava mosaic geminiviruses (CMGs) are transmitted by the whitefly (Colvin et al. 2004) destroying cassava crops. Cassava (Manihot esculenta) is one of the most widely grown staple food crops in sub-Saharan Africa. It is particularly important to the poorest farmers because of its role in food security and as a source of income. Agriculture in tropical and subtropical regions are most threatened, with crops such as beans, cucurbits, peppers, cassavas and tomatoes particularly being affected (Brown, 1994). Tomato yellow leaf curl virus (TYLCV) limits tomato production in several geographic regions, including the Middle East and Far East (Zeidan et al. 1998).          Location Specific Impacts: East Africa (Africa)   Agricultural: Colvin et al (2004) states that "Cassava (Manihot esculenta) is one of the most widely grown staple food crops in sub-Saharan Africa. It is particularly important to the poorest farmers because of its role in food security and as a source of income." Unfortunately, in several East African countries cassava mosaic disease (CMD) and cassava mosaic geminiviruses (CMGs) are destroying cassava crops. Both CMD and CMG are transmitted by the whitefly, Bernisia tabaci." Australia   Pathogenic: In Australia, tomato leaf curl virus (TLCV) was first reported in 1970 in the Northern Territory (Behjatnia et al 1996) and has occurred ever since, causing severe, or complete loss, of tomato crops. It is readily transmitted by the Australian indigenous biotype of Bernisia tabaci, which utilizes the tomato as a feeding, but not reproductive host. Guinea   Pathogenic: Bemisia tabaci is a vector for cassava mosaic virus disease (CMD) India   Pathogenic: Cotton leaf curl disease, caused by a geminivirus, has been detected, using viral nucleic acid based hybridisation tests, in infected hosts and weeds. Cotton leaf curl was transmitted by whitefly, Bernisia tabaci to Gossypium hirsutum varieties, which showed typical symptoms of the disease (Sharma et al 2004). Senegal   Pathogenic: Bemisia tabaci is a vector for cassava mosaic virus disease (CMD) Uganda   Pathogenic: Sweet potato virus disease (SPVD), the most damaging disease of sweet potato, Ipomoea batatas, in Uganda, results from dual infections of sweet potato feathery mottle virus (SPFMV), vectored by aphids, and sweet potato chlorotic stunt virus (SPCSV), vectored by whiteflies.