Brief Summary of Minutes of Annual Meeting

Carl Strausbaugh, host of this years meeting, opened the meeting, made introductions, and explained the purpose of the meeting. Speakers were Rebecca Creamer, Carl Strausbaugh. Phil Miklas, Marty Draper, and Bob Hammon. Carl Strausbaugh gave an overview of curly top in Idaho and discussed research on the curly top isolates infecting sugarbeet in the western US. Curly top virulence increased in the 1960s. The egg stage lasts 43.8 days at 60F, the nymphal stage 75.4 days and 65F, and brood development lasts 1-2 months. The mated females overwinter and there are three generations of leafhoppers with egg laying beginning in March. A survey on curly top in the western US in sugarbeets gave combinations of BSCTV and BMCTV and sometimes BCTV in every state. Tests of single fields showed that mixed infections occurred. Generally the curly top species have not changed significantly since Stengers previous work in 1994-95 except in Idaho. BCTV was found in small numbers in Idaho and Colorado and not in other states. Rebecca Creamer discussed the role of weeds in curly top epidemiology and reported on a survey of weeds as hosts of curly top virus. She also outlined the distribution of curtovirus species among the weeds, with BSCTV, BMCTV, and PeYDV (pepper yellow dwarf virus) the primary species. Distribution of the three species varied among the years. Marty Draper gave a report by conference call on the 2008 Farm Bill. He explained the new organizational system and talked about the components of the Roadmap for Agriculture Research and Extension Education. CREES will be replaced by NIFA (National Institute of Food and Agriculture). The funding will be in the form of Specialty Crops Initiative, funding for organic research, AFRI (Agricultural Food Research Initiative) = former NRI+IFAFS. The IDC cap will increase from 20 to 22%. The split has been delineated at 60% fundamental research, 40% applied. Not less that 30% of the funding will go to research integrated with extension or teaching. Reports on curly top in western states were given by several individuals. Bob Hammon gave his report on Colorado by conference call. He said that over the last three years, the highest incidence he observed was 75% losses in tomatoes. He reported on two field trials. In one he compared the use of Admire Pro applied in drip as a drench under plastic at planting, with Actiguard as a foliar treatment, the combination of Admire Pro + Actiguard, and a control. The untreated control had 20% curly top, Admire Pro treated tomatoes had 11% curly top, Actiguard treatment had 15% disease, while the combined treatment gave 6.7% curly top. He also gave a report on the use of colored mulches. He found a lower level of curly top (2.4%) with the use of reflective silver mulch compared to red mulch (12% disease) with the crop on drip. In past years he tested floating row covers, and while they worked well, they were not practical. The California report was sent via email from Rod Clark, CDFA. He explained that the state Beet Curly Top Virus Control Program in California is in jeopardy of loosing its ability to control beet leafhopper populations in rangeland due to increased exclusions by USFWS within endangered species habitat. The programs permit process was bogged down for over a year, so insecticide treatments could not be made this past spring in rangeland, resulting in heavy curly top infection in tomato fields. Both curly top and TSWV are having significant impacts on processing tomato fields in several areas. Marvin Clary (Border Foods) sent his perspectives on curly top in New Mexico by email. He said that there has been generally low infestations in the 5-10% area but with some hot spots in the 30-40% range. One field near Janos, Mexico had 80% infection on jalapeno transplants. The worst fields were those emerging in late April and early May. Some watermelons are also infected. There is a lot of bacterial leaf spot in peppers. Carl Strausbaugh gave the report for Idaho. It was a particularly cold year, with snow in mid June. Curly top levels were generally low, going from <5% increasing on a gradient across the state. The worst year in recent memory was 2004 where fields had 100% infection, although the sugarbeet had some level of resistance. Phil Miklas gave the report from Washington. He said that while curly top is present every year at some low extent, the worst years were 2000 and 2002. This year was about 1% in commercial fields, although his susceptible check rows had 50% incidence. Ed Curry (Curry Seed) reported from Arizona. He said that the curly top levels were generally low at the 5-10% levels. Carl Strausbaugh spoke about control of controlling BCTV in sugarbeet. In 2008, almost 100% of the sugarbeet in Idaho are transgenic, containing the Round-up Ready technology. He reported that the disease ratings in the field and curly top nursery were highly correlated as were the root yields and nursery ratings. He also found that decreasing the disease rating one step (from 4 to 3) increased yields 3 tons/acre. He tested Poncho Beta (Bayer) and Cruiser (Syngenta) as seed treatments. Both gave increased yields and decreased curly top. Poncho Beta gave approximately 60 day control and also controlled leafminer, root maggot, black bean aphid, and root aphid. Cruiser caused some phytotoxicity resulting in delayed emergence. Control of BCTV in Idaho on sugarbeet is based on the use of resistant hybrids, planting early to allow plants to grow before the leafhopper flights, and the use of systemic insecticides. Phil Miklas reported on the bct gene for resistance to curly top virus in snap beans. The germplasm is from a Moncayo X Primo cross. The SCAR marker for the resistance maps to an area with bean golden yellow mosaic begomovirus resistance, even though the plants are susceptible to BGMV. The Moncayo parent is resistant to bean dwarf begomovirus, while the Primo parent is susceptible. The bct gene explains 77% of the phenotypic variation from reactions to BDMV. This is the first QTL for curly top resistance in bean and is from the Andean bean gene pool. Miklas also identified a line of cranberry beans (G122) that was resistant to curly top, but didnt have the bct gene. G122 is the progeny of a Taylor X Hort cross. This minor QTL may confer resistance to other geminiviruses. Rebecca Creamer reported on current efforts to identify the mode of resistance to curly top in tomatoes. Leafhopper testing suggests that non-preference may play a role in what is likely a form of tolerance. She also reported on efforts to identify tolerance in chile. The best candidate thus far is Tabasco and a novel Nu Mex cayenne. In subsequent discussions Carl suggested that sugarbeet seed treated with Poncho Beta should be tested as a trap crop around chile plantings. Participants toured the Beet Sugar Development Foundation leafhopper rearing facilities, the curly top nurseries, and bean breeding trials for curly top resistance. There was a brief discussion as to the 2009 meeting, with two ideas for locations. One option is for Judy Brown and Ed Curry to host the meeting in Arizona. A second idea is to have the meeting in Washington, perhaps hosted by Phil Miklas and Richard Larsen.

A collaborative project for 2009 was established at the meeting between Rebecca Creamer, Ed Curry, and Stephanie Walker.

Strausbaugh, C. A., Rearick, E., and Camp, S. 2008. Influence of curly top and Poncho Beta on storability of sugarbeet. J. Sugar Beet Res. 45:31-47. Strausbaugh, C. A., Gillen, A. M., Camp, S., Shock, C. C., Eldredge, E. P., and Gallian, J. J. 2007. Relationship of beet curly top foliar ratings to sugar beet yield. Plant Dis. 91:1459-1463. Singh, S., Terán, H., Lema, M., Webster, D., Strausbaugh, C. A., Miklas, P. M., Schwartz, H. F., and Brick, M. A. 2007. Seventy-five years of breeding dry bean of the Western USA. Crop Sci. 47:981-989. Strausbaugh, C. A., Gillen, A. M., Gallian, J. J., Camp, S., and Stander, J. R. 2006. Influence of host resistance and insecticide seed treatments on curly top in sugar beets. Plant Dis. 90:1539-1544. Valasquez-Valle, R, Creamer, R., Medina-Aquillar, MM. 2008. First report of beet mild curly top virus infection in chile pepper in North Central Mexico. Plant Disease 92:650. Wintermantel, WM. 2007. Mapping of curly top incidence and determination of genetic variation among viruses responsible for curly top in California. Journal of Sugarbeet Research 44:163-164. Wintermantel, WM. 2007. Development of novel sources of resistance to beet curly top virus through virus-induced gene silencing. Journal of Sugarbeet Research 44:136-137.