|
|
Pierce's disease research yieldsnew information for wine-grape growers Texas A new generation of insecticides could buy vineyard owners time from the ravages of Pierce's disease, an expert recently told a group of researchers, vineyard owners and others involved in the wine industry during a two-day conference. The new insecticides wouldn't be a permanent solution, said Dr. Nick Toscano, University of California at Riverside entomologist, but would serve as a "stop-gap" until more resistant wine-grape varieties are developed and better technology and growing practices are identified. More than 60 people heard from Toscano and numerous other experts during the annual Texas Pierce's Disease Research and Education Program Review and PD Symposium held April 29 and 30 in Driftwood. "This was an opportunity for wine-grape growers and winery owners to learn more about Pierce's disease from the principal investigators conducting trials and how the results may benefit the grower," said Dr. James Supak of Texas AgriLife Research. Supak, who is the agency's coordinator for the Texas Pierce's Disease Research and Education Program, said there has been significant progress toward identifying the sources of the disease and how it is transmitted to susceptible wine grapes. According to the Texas Wine and Grape Growers Association, the disease, which is caused by the xylella fastidiosa bacterium, costs the wine industry millions of dollars each year in lost production. "There are still many unknowns about PD, but enough has been learned for us to develop some practical and beneficial recommendations to help commercial vineyard owners better manage the disease," Supak said. "Insecticides can now provide better protection against the spread of Pierce's disease by the glassy-winged sharpshooter and similar insect vectors," said Toscano during his keynote presentation. Toscano has been instrumental in promoting the use of imidicloprid in citrus groves and vineyards. "The use of neonicotenoid insecticides in managing insect pests of the vineyard is the first line of defense against xylem-feeding insects known to spread Pierce's disease," he said. "But the real long-term solution to this disease will come through the application of genetics and the development of more PD-resistant wine-grape variety types, including those developed from more disease-resistant native grape varieties." Other aspects of Pierce's disease addressed at the two-day event included the geographic spread of the disease, additional insect vectors of disease transmission, the xylella bacterium and bug interface, common weeds the xylella bacterium can infect, and natural enemies of the bacterium. Dr. Mark Black, a plant physiologist with the Texas AgriLife Extension Service, said while many wine-grape growers are still growing European wine-grape varieties, these varieties are all susceptible to the disease. "We're encouraging wine-grape growers in Texas to shift their focus to varieties that are less susceptible to PD," he said. Black and other AgriLife scientists are currently growing, testing and ranking various wine-grape rootstocks for resistance to the disease, as well as combining rootstock with scions in the hopes of slowing disease development and maintaining production. Unique scion-rootstock combinations and improved management practices are some of the ways growers can "fine-tune vigor and fruit load," he said. "To date, we've evaluated 12 commonly used root stocks that are commercially available, which include three native species and nine complex hybrids of native wine-grape root stock with European root stock," Black said. The importance of finding a long-term solution to the disease was further emphasized during the research review when discussion turned to positive testing for the xylella bacterium in West Texas and the state's High Plains regions. The High Plains were previously considered unaffected by Pierce's disease. "We have gotten positive results back from the testing, but the vineyards from which the tests came back positive were those that have gone into decline due to substandard care," said Bobby Cox, a wine-grape grower in the High Plains who presented during the event's research review. "Now we're seeing symptoms of PD in grape-growing areas where it hasn't been seen before," said Jim Kamas, an AgriLife Extension fruit specialist and Pierce's disease expert based in Fredericksburg. "So we're carefully monitoring the situation to determine the extent and degree of the infestation." Kamas noted there is likely a "novel insect vector for the disease" and that more research is needed to determine what potential insect vector or vectors--or other cause--is responsible for the movement of the xylella bacterium into those areas. "Pierce's disease research is important to the present and future of the wine industry in Texas, California and other wine-grape producing states," said Gene Estes, a conference attendee and president-elect for the Texas Wine and Grape Growers Association. "The research that's been done on genetics, insect vectors, environmental influences and other aspects related to PD has already greatly helped the industry," said Estes, owner of Post Oak Vineyards in Burleson. The research being done on Pierce's disease will lead to even better steps which wine-grape growers can take to control the disease, he said. "There's been a lot done in the past three years or more in the area of PD research; a lot more will be done in the future," Estes said. "This research will eventually lead to even better vineyard management practices for the wine-grape grower." For more information on Pierce's disease research conducted by AgriLife Research and AgriLife Extension, go to http://piercesdisease.tamu.edu/. 6/2/08 Date: 5/30/08
Copyright/Privacy
Copyright 1995-2011. High Plains Publishers, Inc. All rights reserved. Any republishing of these pages, including electronic reproduction of the editorial archives or classified advertising, is strictly prohibited. If you have questions or comments you can reach us at High Plains Journal 1500 E. Wyatt Earp Blvd., P.O. Box 760, Dodge City, KS 67801 or call 1-800-452-7171. Email: webmaster@hpj.com |
|
