Why hasn’t anyone thought of this before?
It turns out that a fence may protect vineyards and nursery
stock from the menacing glassy-winged sharpshooter, a pest capable
of destroying the grape industry.
Why hasn’t anyone thought of this before?
It turns out that a fence may protect vineyards and nursery stock from the menacing glassy-winged sharpshooter, a pest capable of destroying the grape industry.
“In retrospect, it does seem like a no-brainer,” said Matthew Blua, a researcher at the University of California, Riverside. “This is a particularly expensive tactic. Thus, it is useful only for high-value crops, including nursery stock and in some cases, vineyards.”
Blua said his research, conducted with his associate Rick Redak, and David Morgan of the California Department of Food and Agriculture, was informed by farmers in Israel who use a similar tactic to keep white flies away from tomatoes.
The fence’s key defense is its height of about 16.4 feet, a loftiness that even the most athletically gifted sharpshooters can’t reach. But at about $18 a linear foot, Blua isn’t talking about just any fence. It needs to be constructed with a special ultraviolet-protective cloth pulled against wire posts, tight enough to keep sharpshooters out yet not so tight that it catches too much wind.
Fortunately for South Valley vintners, most of who have family-run operations, their colleagues in southern California will probably pick up most of the tab. The sharpshooter is much more prevalent in the south and migrates north in nursery stocks. Jay Van Rein, spokesman for the CDFA, which sponsored the research, said that most nursery owners will see the fence as a worthwhile investment.
“In some industries such as retail nurseries, the value of the plants and the high rates of sales they have in a year might make something like this feasible,” Van Rein said. “The prevalence of sharpshooters is much higher down there than where the grapes are grown. It’s always better to keep it out of nursery stocks.”
The Sharpshooter was discovered in California in 1999. The insect preys on a variety of crops but carries a plague, Pierce’s Disease, that is particularly lethal to grapevines. The disease essentially clogs the plumbing in a vine, making it impossible for the fruit to receive water and nutrients.
The state’s grape growers pay an assessment each year to combat the disease. This year, the final year of the levy, the assessment is $2 for every $1,000 in wine grape sales, which Van Rein said will raise as much as $5 million to fight Pierce’s Disease. Growers are currently voting in a referendum via mail to extend the assessment.
To be successful, the measure must receive a majority of the votes cast by the growers who currently pay 65 percent of the total assessment, or 65 percent of the vote cast by the growers who pay at least half of the assessment. Voting closes July 14. Results will be announced in early August.
