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A European weed, London rocket (Sisymbrium irio), which is distributed from coastal and interior southern California to Modoc County in northern California, has been found to harbor Spiroplasma citri. We have succeeded in demonstrating transmission to London rocket by leafhoppers, Scaphytopius nitridus and Circulifer tenellus, and from these field plants to periwinkle (Vinca rosea) by C. tenellus.

Fusarium wilt of watermelon, caused by Fusarium oxysporum f. niveum, can be a limiting factor in California watermelon production. Warm weather, which favors watermelon production, also favor the disease. The fungus lives in t he soil for many years, and therefore rotation, although helpful, is not the answer to the problem. Studies were initiated in 1971 to test various watermelon cultivers for resistance to the Fusarium wilt fungus.

Before 1974, most of the 160,000 pounds of wet solid waste produced annually in San Joaquin County fruit and vegetable processing plants was disposed of in cut-and-fill dump sites. As this means of disposal became less desirable, incorporation of cannery waste into soil used for forage production was considered. Since cannery wastes are high in nitrogen content, it was necessary to determine whether such forage plants would accumulate levels of nitrate-nitrogen toxic to livestock.

Currently, typical California apple orchards have large trees that usually require three operations per year from tall ladders. If ladders could be eliminated or their size reduced, orchard safety could be improved; time could be saved climbing and moving ladders; and a broader spectrum of labor (women, teenagers, and older persons) might be available for orchard operations, Smaller, more closely spaced trees could also produce better colored fruit, allow easier and improved pest control, increase early production, and provide quicker return on investment.

Much of the new land being developed in Glenn County is comprised of Tehama and Kimball series soils, which, because of their structure and other profile characteristics, are often considered problem soils. Alfalfa hay yields on these soils range from less than 4 tons to 8½ tons per acre, depending on management. The alfalfa is generally rooted in less than 2 feet of soil; in summer, primary feeder roots are in a zone usually below 2 inches and above 12 inches.

The development of triticale, a cross of wheat and rye, has spanned many years. Recently, however, the effort have been widely publicized, creating interest among agricultural scientists and arousing the curiosity of growers and consumers. In the past 10 years triticale has shown some promise of becoming a crop for California.

Planting of lettuce and other vegetable crops to a stand in California is often hampered by soil crusting. Materials used to deal with this problem include petroleum mulch, stabilized vermiculite, and phosphoric acid, but, because of cost, application difficulties, and other reasons, they are not always acceptable. Numerous materials and techniques have been tested to solve the problems associated with soil crusting, but none has proved entirely satisfactory. One that shows promise is steer manure, but it must be properly prepared for use. Several experiments have been completed in which specific numbers of lettuce seeds were planted, covered with steer manure, and evaluated for percentage and velocity of emergence and seedling growth rate.

Concern over deteriorating quality of groundwater in Riverside and San Bemardino counties has led to dairy waste disposal regulations in California's largest Grade A milk-producing region, the Santa Ana River Basin (SARB). A study has been conducted to determine the effect of these regulations on the SARB dairy industry and to examine possible alternatives for dairies. The study concludes that milk production may be maintained in the near future if sufficient credit is available to dairymen; otherwise, the dairy industry may eventually leave the SARB unless new waste disposal technology can be implemented.