Unusual Pests Re-Visit San Joaquin Valley Farms

A white, fluffy area on citrus trees once sent a shiver through growers' spines. It may look like a fungus, but it signals the presence of Cottonycushion Scale, an insect that was the major citrus pest at the turn of the century. The pest is making a comeback, but farmers and backyard citrus growers need not worry. The Vedalia beetle, imported from Australia to combat the pest, is still active in the Valley. Left to its own devices, it will control the problem. "A lot of people spray for Cottonycushion Scale after the Vedalia beetle has already gone in and cleaned it up," said Craig Kallsen, the citrus farm advisor for Kern County UC Cooperative Extension. Another pest making a re-invasion is Forest Tent Caterpillar, found in almonds. Despite its name, the pest does not make a tent, but does produce a lot of silk, according to Kern County Farm Advisor James Brazzle. While not considered a serious pest in almonds, the caterpillar can eat a good deal of leaves, exposing the tree to sunburn and reducing leaf surface available for photosynthesis. "We recommend farmers treat early with a soft product, like Bt (Bacillus thuringiensis)," Brazzle said. For more information contact Craig Kallsen or James Brazzle at (805) 868-6200, cekern@uckac.edu.

Using Municipal Waste Water to Irrigate Pastures May Spread Disease

Although cattle are sometimes blamed for infecting human drinking water with microbes, scientists are now looking at whether humans are spreading organisms to cattle when pastures are irrigated with municipal waste water. UC Cooperative Extension Livestock Advisor Franz Rulofson compared calves raised on pastures that had been irrigated with waste water with those raised on dryland or freshwater-irrigated pastures. "There were significantly more calves with both Giardia and Cryptosporidium parvum from the pastures irrigated with waste water, although factors other than the wastewater may have influenced those numbers," Rulofson said. "This study tells us we need to be concerned about how we treat water and what the final uses are." Studies have shown calves are much more likely to be shedding pathogens than full-grown cattle. Animals that shed the microorganisms rarely show signs of ill health. "The bottom line is, we know we have it, we need to control where those animals go until they're about four months old. Then they appear to become immune to it and quit shedding," he said. "We're helping ranchers develop plans to manage it." For more information, contact Franz Rulofson at (209) 533-5695, fcrulofson@ucdavis.edu.

Residents of Mendota are Living Healthier

Mendota is an isolated, rural community that suffers from high poverty rates, but residents now have at least one reason to feel better. The city was selected for a state-funded UC Cooperative Extension model program designed to promote a healthful lifestyle. Focusing primarily on the schools, UCCE has enlisted 21 high school student "advocates" to take a message of eating right and staying active to younger students and to adults. A first victory was proving the palatability of low fat 1% milk, which after a series of taste tests is now the only milk served in the Mendota Unified School District. Diet and physical activity information are taught to all 9th- and 10th-grade students as part of their mandatory PE program. "We're hoping the children will take the healthy living message home and share it with their parents," said Patty Minami, the program representative for UCCE. In case some adults aren't getting the message, the high school advocates set up milk tasting stations at a supermarket in town. And in September, a 24-hour relay provides the centerpoint of a healthy living festival for the entire community. For more information, contact Patty Minami, (209) 456-7285, plminami@ucdavis.edu.

Diet Supplements for Insects? A Predator Power Bar, Maybe?

Scientists are spraying a tempting smorgasbord of flavors onto fields in an effort to lure beneficial insects onto farms and give them an incentive to stay there, reducing the need for pesticides. UC Davis Entomology Professor Les Ehler is experimenting with food sprays, which mimic nectar, pollen and honeydew in fields, giving insects something to tide them over when pests are not yet in abundance or the beneficial insect is in a developmental stage that prefers such goodies. Sugar beets, for example, a biennial grown as an annual in California, offers no nectar or pollen for insects. Honeydew is often non-existent because aphids are controlled. Ehler tried spraying with a mixture of yeast, sugar, molasses and water. He also mixed the concoction with vermiculite and let it dry to form a "power bar" to be distributed in chunks in the field. In his backyard he found some bugs "just love it." But, alas, something is still missing, since it didn't bring predators to sugar beet fields in numbers significant enough to control pests. "The problem is not the nutrients, it's the formulation," Ehler says, adding that perhaps the addition of a fictional "Essence of Sugar Beet" would attract more bugs. To illustrate his point Ehler holds up a bag of dry cat food. "Can you imagine a carnivore eating this?" he asks. "And they fight for it. It's the formulation." For more information, contact Les Ehler at (530) 752-0484, leehler@ucdavis.edu.

Jeannette Warnert
Public Information Representative
UC Regional Office
550 E. Shaw Avenue
Fresno, CA 93710