New lab techniques should help speed development of guayule, a desert shrub, as a source of high-quality hypoallergenic latex. The techniques are for extracting natural latex from guayule samples and measuring the amounts yielded. Soon, gloves and other medical, industrial and home products made from natural latex of guayule, Parthenium argentatum, may provide a safe alternative for the estimated 20 million Americans allergic to latex from the most common source—rubber from the Brazilian rubber tree Hevea brasiliensis. Before now there were no reliable, standardized lab procedures for quickly and easily extracting and measuring the latex yield from guayule branches. The procedures that ARS scientists in Arizona and California developed are patterned after those likely to be used in large-scale commercial production. The techniques obtain at least 90 percent of the latex from samples ground twice at 1 minute per grind, and at least 99 percent from four grinds. Breeders can use the techniques to screen for the highest-yielding guayule plants. And tomorrow's guayule growers can use them to determine the best methods for growing and storing the shrubs so they'll yield the largest amounts of high-quality latex.

U.S. Water Conservation Laboratory, Phoenix, AZ
Francis S. Nakayama, (602) 379-4356, ext. 255, fnakayama@uswcl.ars.ag.gov
Western Regional Research Center, Albany, CA
Katrina Cornish, (510) 559-5950, kcornish@pw.usda.gov

An artificial diet for rearing Colorado potato beetles should expedite laboratory research to develop new chemical or biological controls against the crop pest. The beetle’s grublike larvae eat the leaves and stems of potato, tomato and eggplant crops, costing an estimated $150 million annually in losses and chemical controls. The artificial diet, designed by ARS researchers, comes at a time of growing concern that the beetle may soon resist standard insecticides like Admire. To find a suitable replacement or test a biological alternative like parasitic wasps, scientists need large numbers of the beetles. This means rearing them in the lab on a steady supply of potato plants. But growing the plants is costly and time-consuming—hence the need for an artificial diet. Originally, the beetle diet included potato leaf powder, as well as oats and other ingredients. However, the scientists have since replaced most of the leaf powder with lettuce. Not only is lettuce cheaper, it is easier to obtain since it is widely available at grocery stores. In tests, about 90 percent of the beetles ate the diet. About 6 generations have been reared on it so far. Scientists are now comparing each generation’s average weight, growth, egg production and other characteristics. Once perfected, the artificial diet should allow for relatively inexpensive, year-round research on the beetle.

Insect Biocontrol Laboratory, Beltsville, MD
Dale Gelman, (301) 504-8909, gelman@asrr.arsusda.gov

A new lure may help improve detection and control of the Malaysian fruit fly, a housefly-sized pest of crops, including peppers, tomatoes, eggplant, cucumbers and gourds. ARS scientists in Hilo, HI, and Albany, CA, developed the lure in tests with approximately 1 million lab-reared Malaysian fruit flies, known as Bactrocera latifrons. The researchers designed the lure for use in standard insect traps. Pest control workers in states such as California monitor traps year-round to detect outbreaks of other insects—such as the infamous Mediterranean fruit fly—before they build up. The Malaysian fruit fly, a medfly relative, is now established on all major islands in Hawaii. If undetected in contraband produce, it could hitchhike to the continental United States and pose a considerable threat to agriculture. The lure combines a colorless chemical called alpha-ionol and cade oil, a dark brown liquid from prickly juniper, Juniperus oxycedrus. Easy to make, the lure doesn’t require solvents or additives. Earlier, ARS scientists in Hawaii and Maryland patented alpha-ionol as a Malaysian fruit fly lure. Later experiments in Hawaii showed adding cade oil to alpha-ionol makes the lure more effective. The researchers are seeking a patent for the invention. (PATENT APPLICATION NO. 09/120,521)

U.S. Pacific Basin Agricultural Research Center, Hilo, HI
Grant T. McQuate, (808) 959-4300, mcquate@aloha.net

Hawaiian-grown bananas, shipped to mainland and overseas markets under guidelines that ARS helped develop, should not harbor oriental or Mediterranean fruit flies. ARS scientists used thousands of freshly harvested bananas from more than a dozen plantations throughout the Hawaiian islands to demonstrate conditions for safely shipping the island-grown fruit without chemical or other treatments to thwart the pesky fruit flies. That's a boon for growers and consumers alike, because disinfestation treatments may add to costs and hasten spoilage. Fresh fruit leaving Hawaii for the U.S. mainland or other markets must be free of any hitchhiking medflies or oriental fruit flies. The pests are a constant threat to mainland agriculture; they can attack more than 200 fruits and vegetables. At least four kinds of commercial bananas won't carry these insects, the scientists determined, if the fruit is shipped full-size, green skinned, and without cuts or punctures. As a result, USDA's Animal and Plant Health Inspection Service late last year approved new, workable regulations for shipping the bananas without disinfestation treatments. The lab and outdoor experiments were conducted by ARS scientists and colleagues from the University of Hawaii Cooperative State Research, Education and Extension Service and the Hawaii Banana Industry Association. Hawaii growers produced about 21 million pounds of bananas, worth about $7 million, in 1998. Bananas are a good source of potassium, fiber and vitamin C.

U.S. Pacific Basin Agricultural Research Center, Hilo, HI
John W. Armstrong, (808) 959-4336, jwa@aloha