Curly Top Virus Biology, Transmission, Ecology, and Management

WERA-1007: The group’s collaborative research has provided necessary background information on curly top virus and tools to help with its management, and has kept the disease’s profile high so that growers and industry representatives plan for potential disease management and request more information about disease potential in advance of the planting season, instead of waiting to respond after the disease problem is prevalent in the field.

Beet curly top virus (BCTV) infects a variety of vegetable crops including tomatoes, beans, potatoes, spinach, and beets–pictured here showing symptoms of infection. Photo courtesy of Colorado State University.

Issue

Beet curly top virus (BCTV) is the most widespread geminivirus (DNA virus that infects plants) in the United States. It is endemic in the West, causing economic damage to a wide variety of crops. Transmitted by the beet leafhopper, Circulifer tenellus, the virus infects a broad host range from many plant families. The leafhopper vector also feeds and breeds on an extensive range of plant hosts and can migrate considerable distances. Management of this viral pathogen and its leafhopper vector has proven difficult, and a sustainable management program is needed. Only when many individuals work together across state lines will significant progress in management of BCTV be possible. WERA-1007 meets to discuss, assess, and prioritize required research on BCTV genetics, vector biology and genetics, weed ecology, and disease management and to coordinate interdisciplinary research at a regional level. In addition to this needed coordination, another expected outcome is that the agricultural industry will know about new research on BCTV as it is being done, instead of after publication, and will be able to influence the direction of the research.

What has the project done so far?

Several funded collaborative projects on curly top were undertaken among working group members. One looked at transmission of curly top by the beet leafhopper to resistant tomato varieties. A second collaborative project was a screening for resistance to curly top in chile peppers, and a third compared viral infection in insects with plant infection. A collaborative project for 2011 was established to study the mechanism of resistance to curly top in dry beans.

Floating row covers used to protect newly transplanted tomato plants from beet leafhopper, the vector of curly top virus. Photo courtesy of New Mexico State University.

Impact Statements

The group has made an impact on curly top in the western United States. It has substantially improved communication and collaboration among researchers (including USDA researchers) and Extension personnel. It has helped keep the profile of the disease high so that growers and industry representatives plan for potential disease management and request more information about disease potential in advance of the planting season, instead of waiting to respond after the disease problem is prevalent in the field. Resistance to curly top in several hosts was reported. The use of management strategies, such as reflective mulch and row covers, was tested and reported. A better understanding of insect vector migration, feeding preferences, and vector activity was reported. Several reports were made on disease incidence in different locations in the West. Information on viral recombination was presented. These types of research and subsequent papers provided necessary background information on the nature and extent of curly top disease and the potential for predicting disease occurrence in future years. This research also helped predict the types of plant disease resistance screening that needs to occur to better assess potential new plant varieties.

Research Needs for Future Impacts

The primary research needs are to 1) understand the reasons for rapid development of new strains of curtoviruses (viruses that cause curly top disease), 2) develop additional plant varieties resistant to curtoviruses, 3) better predict leafhopper population movement, and 4) develop more cost-effective, practical methods for disease management.

Contact Information

Steven Loring, sloring@nmsu.edu