Brief Summary of Minutes of Annual Meeting

Bob Hammon gave an overview of western Colorado agriculture. It is primarily irrigated from one of three rivers. Beef cattle are the largest economic product, and alfalfa and grass hay are the largest crops. That portion of the state has substantial acreages of sweet corn and peaches. Tomatoes, which are the crop with the largest curly top losses, are shipped to a four state area. Stephen Peinado gave an overview of curtoviruses in New Mexico and discussed research on the curly top isolates infecting chile in the state. The viral species BSCTV, BMCTV, Pepper yellow dwarf virus, and Pepper curly top virus have been found infecting peppers. New viral species occur through recombination. PCR, quantitative PCR, and ELISA are used to detect virus in peppers in New Mexico. Rebecca Creamer gave an overview of the beet leafhopper in New Mexico and a review of its behavior in the state. A comparison of the feeding preference of the beet leafhopper in California and New Mexico showed that they differed between populations in the two states. Shree Singh presented results from his dry bean breeding program looking at curly top resistance in small, medium, and large seeded beans. While none of the selections showed immunity, moderate to high levels of resistance was found in all three groups of which the small-seeded beans from Central America showed the highest resistance. Beans with resistance to curly top also had resistance to several whitefly-transmitted geminiviruses. Rebecca Creamer presented work on screening for curly top resistance in tomatoes and peppers. Vascular puncture and leafhopper transmission were used in complement with stylet sheath staining to identify tolerance/insect non-preference in two peppers and several tomato varieties. Bob Hammon presented results on management of curly top virus from several years. Losses from curly top were very bad in 2003-2005 in western Colorado on several crops, but Roma tomatoes were particularly hit. Trials compared wall-of-water with opening planting, early with late planting dates, floating row covers with open planting, red with reflective mulch, and use of tolerant varieties. Reflective mulch decreased disease and was economically effective. Jessica Milner presented results of field trials managing curly top in peppers and tomatoes in New Mexico. Sugarbeets planted at the field margin as a trap crop did not reduce curly top in chile. Floating row covers worked better than kaolin spray at decreasing curly top while maintaining good yield of tomatoes. Reports on curly top in western states were given by several individuals. Carl Strausbaugh sent his report on sugarbeets in Idaho. It was a cool wet spring, so there has been only low levels of curly top in southwestern Idaho and in southcentral and southeastern Idaho there is almost no detectable disease. Rod Clark, CDFA, sent an extensive report on the curly top virus control program in California. A dry summer and fall and cool foggy winter, followed by a wet spring produced more grasses and fewer beet leafhoppers I the Central Valley. As foothill weeds dried, aerial insecticide applications were made to 31,00 acres in mid April to 3 counties. Imperial and Palo Verde Valleys had more weeds and required spot treatments to roadside plants on more than 1,100 acres. They collected plant and leafhopper samples which were processed at UC Davis by Dr. Robert Gilbertson's lab. BMCTV was detected in the San Joaquin Valley and BSCTV was detected in Imperial Co. Tomato spotted wilt virus has been an increasing problem and symptoms in tomatoes can easily be confused with those caused by curly top. Questions and comments for curly top research were raised by the attendees. Can functional disease prediction systems be established for western Colorado and southern Idaho? What causes the shifts in curtovirus species or strains? Should disease screening change based on which curtovirus strains are found in an area? What is the mechanism of curtovirus resistance that is found in dry beans? There was a brief discussion as to the 2011 meeting, with ideas for locations. Suggestions were made to hold the meeting in New Mexico, Central Valley of California, or eastern Washington.

A collaborative project for 2011 was established at the meeting between Rebecca Creamer and Shree Singh to study the mechanism of resistance to curly top in dry beans.

Durrin, J. S., Nikolaeva, O.V., Strausbaugh, C. A., and Karasev, A. V. 2010. Immunodetectionof two curtoviruses infecting sugar beet. Plant Disease 94:972-976. Chen, L-F., Brannigan, K., Clark, R., Gilbertson, R. L. 2010. Characterization of curtoviruses associated with curly top disease of tomato in California and monitoring for these viruses in beet leafhoppers. Plant Disease 94:99-108.