Resources

Websites

• APSnet
• Global Invasive Species Database
• Tropical Whitefly IPM Project
• IPM Images

For further reading:

• Whitefly-transmitted sweet potato viruses
• Breeding for resistance to whitefly-transmitted geminiviruses
• Control strategies for sweet potato virus diseases in Africa
• Adaptation of Bemisia tabaci to cassava
• Cultural practices for managing Bemisia tabaci and associated viral diseases
• AVRDC Fact Sheet Pepper Diseases
• AVRDC Fact Sheet Tomato Yellow Leaf Curl Virus
• Whitefly and Whitefly-Borne Viruses in the Tropics: Building a Knowledge Base for Global Action

Whitefly-Transmitted Diseases

Whiteflies damage crops in a number of ways. First, direct damage is caused by the feeding of nymphs and adults which results in removal of plant sap, the breakdown of stem and leaf tissue, and physiological damage such as stunting and chlorosis. The whiteflies then secrete a substance known as 'honeydew', which accumulates on the plant and nourishes the growth of molds such as black sooty mold. Lastly, whiteflies transmit several serious plant pathogens.

Bemisia tabaci is known to transmit more than 100 plant diseases. Approximately 90% are geminiviruses of the genus Begomovirus and include:

• bean golden mosaic virus
• cassava mosaic virus
• tomato yellow leaf curl virus
• cowpea golden mosaic virus
• cotton leaf curl virus
• pepper golden mosaic virus
• tobacco leaf curl virus

Begomoviruses can cause crop losses of 20% to 100%. Common symptoms are yellow mosaics, leaf curl, plant stunting, yellow veining, and vein thickening.

Whiteflies also transmit criniviruses, such as cucurbit yellow stunting disorder virus and sweet potato chlorotic stunt virus; ipomoviruses, such as cassava brown streak virus and sweet potato mild mottle virus; and carlaviruses, such as cowpea mild mottle virus.

In tropical and subtropical regions, crops particularly affected by whitefly-transmitted diseases include cassava, beans, cucurbits, peppers, and tomatoes.

Sources:

AVRDC. 2001. 'Tomato Leaf Curl Virus (ToLCV)'
http://www.avrdc.org/LC/tomato/tylcv03.html

Global Invasive Species Database. 2005. 'Bemisia tabaci (insect) Impacts.'
http://www.issg.org/database/species/impact_info.asp?si=106&fr=1&sts=

Jones, D. 2003. 'Plant viruses transmitted by whiteflies.'
European Journal of Plant Pathology 109:195-219.

McAuslane, H. 1997. Featured Creatures. University of Florida.
http://creatures.ifas.ufl.edu/veg/leaf/silverleaf_whitefly.htm

Morales, F. 2001. 'Breeding for resistance to whitefly-transmitted geminiviruses.'
http://www.oardc.ohio-state.edu/tomato/morales.pdf

© 2009 Lisa Moore, Entomology Dept., Virginia Polytechnic Institute and State University.