Calag Archive

Not available – first paragraph follows: Between 1950 and 1980, the average number of farmworkers employed in California agriculture increased 3 percent, from 218,000 to 224,000, while the average employment of farmers and family workers declined 52 percent, from 132,000 to 64,000. Statewide statistics are not always reliable indicators of what has happened to the farm labor market in specific commodities, and the apparent stability of average farmworker employment obscures the dramatic changes that have occurred in particular commodities.

Not available – first paragraph follows: Growers occasionally wish to prune grapevines before the leaves have shed naturally. This is most likely to happen in the Coachella Valley of southern California where frost does not kill the leaves.

Not available – first paragraph follows: Warm-season forages, highly productive in the world's tropical and subtropical regions, have been grown in the southeastern United States, but only bermudagrass (Cynodon daclylon (L.) Pers.), sudangrass (Sorghum sudanense (Piper) Stapf.), and dallisgrass (Paspalum dilalatum) have been grown extensively in California. However, rhodesgrass (Chloris gayana Kunth). and kikuyugrass (Pennisetum clandestihum Hochst. ex Chiov.) have been rusted in California. Since 1950 many improved tropical forages have been developed, but until 1980 no effort had been made lo screen a wide selection of these forages to assess their adaptability lo California climates.

Not available – first paragraph follows: Development of insecticide resistance of the leafminer, Liriomyza trifolii (Burgess), in chrysanthemum and gerbera greenhouses throughout California has resulted in serious damage. It has been estimated, for example, that California's chrysanthemum industry lost $17 million in 1981. With eventual registration of new insecticides, this “leaf-miner crisis” should be considerably reduced, but the new materials cannot be viewed as long-term solutions to the problem. Growers must strive to maximize the effective field life of these new compounds by using them only when they are needed. In addition, until these new insecticides gain registration, growers must maximize the efficacy of existing compounds.

Not available – first paragraph follows: Spider mites and predatory mites can live all year on deciduous trees and vines. During the growing season they colonize the foliage, and during winter they overwinter under bark and in crevices in a state of dormancy (diapause). Spider mites and predatory mites can move from plant to plant by walking or they can be accidentally transferred by other organisms. Spider mites are also known to disperse aerially, and clusters of spider mite females can sometimes be seen on the tips of branches before their dispersal. Some spider mite species drop from leaves on thin silk strands and are picked up by the wind.

Not available – first paragraph follows: Chemical defoliation is a standard practice on all 1.31 million acres of cotton grown in California (10-year average acreage). In many cases, a second treatment is required to prepare plants for harvest. Irrigation and nitrogen management have a large effect on the amount of vegetative growth produced. Cultural practices that stimulate growth reduce the effectiveness of chemicals.

Not available – first paragraph follows: In sampling for spider mites on cotton, time limitations are important, especially when Tetranychus cinnabarinus (Boisduval) populations can reach levels exceeding tens of thousands per plant. Counting all Tetranychus spp. on a single cotton leaf often requires an hour or more. Consequently, few researchers or pest control advisors take the time for careful sampling.

Not available – first paragraph follows: The citrus red mite, Panonychus citri, is the most important mite pest of citrus in California. It attacks leaves and fruit of lemon, orange, and grapefruit. Heavy infestations during times of plant water stress can cause leaf and fruit drop, twig dieback, and even death of large branches. In 1977, the last year for which data are available, estimated loss statewide due to the citrus red mite totaled $15.9 million.