Calag Archive

Surface disturbance in arid regions — whether it results from abandoned agriculture, overgrazing or recreational activities — often sets the stage for windblown fugitive dust. Revegetation provides the most sustainable soil stabilization but is difficult to achieve in any given year. Widely varying environmental conditions and soil factors make direct seeding unreliable, and transplanting of nursery-grown shrubs does not assure plant establishment, even with supplemental irrigation. In occasional years plants can be successfully established, particularly Atriplex canescens, in the western Mojave Desert. Once vegetation becomes established, it successfully stabilizes the soil surface and reduces blowing dust. However, because successful establishment is infrequent, reliable mitigation of fugitive dust requires that other techniques be used as well.

Wind-blown fugitive dust is a widespread problem in the arid west resulting from land disturbance or abandonment and increasingly limited water supplies. Soil-derived particles obstruct visibility, cause property damage and contribute to violations of health-based air quality standards for fine particles (PM-10). These dry lands are often difficult to revegetate, yet they may require immediate stabilization. We evaluated the effectiveness of three types of mechanical wind barriers, which can be Installed more rapidly and more reliably than revegetation, in suppressing dust emissions. Wind fences, furrows and scattered roughness elements, such as plastic cones, are shown to reduce fugitive dust emissions in areas of the Mojave Desert that resisted revegetation.

Sporadic but increasing incidence of two new diseases, which we have named “black-foot disease” and “Phaeoacremonium grapevine decline,” are taking a toll in California's table and wine grape vineyards (Scheck et al 1998a, 1998b). Although the full scope of the problem is not yet measured, grape growers throughout major production regions in California have reported economic losses from replanting costs. Symptoms of these diseases are almost indistinguishable from each other; the diseases are in fact the same that have occurred in grapevines in other places in the world and in older grapevines here. Our research reveals that black-foot is caused by Cylindrocarpon obtusisporum, and grapevine decline is caused by Phaeoacremonium species (P. aleophilum, P. chlamydosporum, or P. inflatipes).

Verticillium albo-atrum, the cause of Verticillium wilt of alfalfa, was detected consistently in 1989 and 1990 in alfalfa stems collected from a farm in the Mojave Desert at air temperatures (up to 104°F) above the maximum (86°F) for its growth and sporulation. According to research in other areas of the United States and in Canada, infected alfalfa hay is a prime source of inoculum. Resistance to Verticillium wilt in nondormant germplasms was readily developed by selection in six germplasms that have been released.

Computer software has been widely adopted in the tomato processing industry for maintaining pest management records. Although computers have not reduced the time necessary to complete record-keeping requirements, they have shifted some of the burden from growers to pest control advisers (PCAs). Most records kept are pesticide use records required by law or by processors, and the legally required written recommendation. There is little evidence that computer software is being used to maintain or analyze field scouting data.

Identifying the health concerns and barriers to change of diverse audiences is essential to successful nutrition interventions that reduce the risk of chronic disease. This article reports some of the current activities that the Expanded Food and Nutrition Education Program (EFNEP) is undertaking in California to assess the needs of Latino clients and to develop culturally appropriate tools to evaluate changes in food-related behaviors. Latinos in Fresno County reported a number of improvements in food-related behaviors after attending EFNEP nutrition classes, particularly in the areas of reducing fat intake, using a wider variety of fruits and vegetables, shopping wisely and thawing meat safely. Nutrition educators working with Latinos need to find new ways to reach more family members, possibly including classes that involve spouses, newsletters and Spanish radio programs.

A previously undiagnosed problem, called celery petiole lesion (CPL), caused significant damage to coastal celery for several years. A 2-year study found CPL to be associated with applications of the insecticide Dibrom. The product is no longer labeled for use on celery. CPL can be mistaken for two fungal diseases, highlighting the importance of accurate diagnosis of plant problems to reduce unnecessary applications of pesticides.