Seventy nurseries, retailers and landscapers in Sonoma County, already at work to repel the glassy-winged sharpshooter through an inspection program, have launched an education effort to draw the public into the effort.

John Westoby, county agricultural commissioner, says those businesses are inspecting incoming plants, reporting any signs of the pest, and disposing of infected plant material.

In addition to grapes, the insect goes to roses azaleas, many other ornamental plants, oak trees, almond trees, and alfalfa.

Public efforts, Westoby said, are invaluable in preventing the spread of the sharpshooter and the diseases it transmits. The public can play an important role in efforts to combat the pest, and many of the sightings of it in the state were made after residents looked in their back yards.

With funding from Sonoma County grape growers and wineries, Westoby's office is providing training materials, including posters, pamphlets, and videos, in English and Spanish, for employees of participating firms.

Participants also receive certificates of compliance from the ag commissioner, along with a seal to be used in advertising to notify the public they sell only inspected plants.

The pest, said Westoby, “and the diseases it transmit threaten the economic and ecological base of Sonoma County and hamper the ability of all residents and visitors to enjoy the beauty and enormous bounty of the region.”

The public has been responsive, according to Santa Rosa nurseryman Mick Prickett, who noted that the California Association of Nurserymen is cooperating in the effort.

“Best of all,” he said, “customers seem to really appreciate our commitment to providing plants free of the sharpshooter. The program creates loyal customers and a lot of goodwill. We hope everyone in Sonoma County will work together with us and the new education program that's being put together.

“If we can all tell our friends and families about the importance of prevention and early detection, hopefully we can prevent an infestation here.”

Bacterial leaf spot, a lettuce disease that under certain conditions of temperature and moisture can cause significant damage, showed up again this spring in Monterey and Santa Barbara counties. It's been around since the 1960s but with more frequency since the late 1990s.

Steve Koike, Monterey County farm advisor, sent out the following five-point guideline for managing the disease, also known as Xcv:

  1. Use seed that has been tested negatively for Xcv, keeping in mind, however, that standard seed testing procedures are not yet firmly established.

  2. Avoid re-planting in fields with a history of the disease for at least seven months.

  3. Avoid practices that create high humidity and free moisture on foliage (that is, sprinklers).

  4. Where the disease has developed, hasten decomposition of remaining postharvest debris by timely disking and plowing.

  5. Practice good weed management in and around fields to reduce buildup of bacterial populations on weeds.

Initial symptoms of the disease include one-quarter-inch or smaller water-soaked lesions on mature, fully expanded leaves.

These can develop into first a black color and later larger necrotic areas that cause the leaf to fall off. With continued moisture and development, lesions can spread to inner leaves.

If diseased lettuce heads are packed, the lesions may attract secondary decay organisms, causing postharvest disease problems.

e-mail: dan_bryant@intertec.com