Calag Archive

Insect proofing at the time of construction offers new challenge and opportunity to the building and pest control industries. It provides the opportunity for prevention, which is generally less expensive and always more satisfactory than cure. Some insects such as house flies and mosquitoes are not amenable to control by this method—their control is primarily a community or regional problem. Some other insects such as ants, sowbugs, fleas and clover mites, may gain entry into buildings through areas where they don't have to cross the inorganic powders applied during construction. Nevertheless, insect proofing during construction provides the means by which a high degree of long-term control of certain important structural and household pests can be effected.

CROOKED CALF DISEASE has been a problem in the northeast mountain counties of California for many years. Calves are born with this malady and it is demonstrated by malformations of bones in the animal which have a severe to slight crippling effect. Calves may have twisted backs or necks, twisted or bowed legs, cleft palates or combinations of all of these effects.

With the increasing use of sprinkler irrigation on vegetables and other intensively grown crops, has come a need to evaluate herbicide effects. Herbicidal activity is often stepped up under sprinkler irrigation. The degree of crop selectivity may be increased, or decreased, depending upon the herbicide, the soil, the weed species, and the vegetable crop. Sprinkler irrigation advantages have been demonstrated, particularly in areas with saline soils or drainage problems. However, along with increased stands and vigor generally associated with sprinkling, comes an increase in weed populations. And as the cost of hand weeding rises, chemical herbicides become more desirable to the grower. The early use of sprinklers to help germinate the crop and activate the herbicide, even though furrow irrigation is used subsequently, is another promising approach in growing vegetables and other row crops. These observations of recent field tests and commercial applications of herbicides to control weeds under sprinkler irrigation are not to be considered recommendations for use of the herbicides mentioned. For recommendations, refer to University of California Weed Control Recommendations, 1969, or contact local farm advisors.

Significant variations in levels of nitrate ion concentration can occur in analysis of water samples collected from the same well. Variations seem to be associated with at least two factors: (1) the time lag between sampling and actual analysis and (2) time of continuous pumping prior to sampling. A nearly two-fold increase in the level of nitrate ion in water samples from Well 1 occurred within four hours, during which the pump was not running, and a 3 1/2-fold increase after 24 hours—pointing to a multiple aquifer source of water, one or more aquifers of which may be the source of NO_a concentration in the well water. The change in nitrate ion concentration, with time after sampling, suggests that some undetermined factor is involved that changes nitrates to some other form of nitrogen.

THE TRADITIONAL METHOD of harvesting citrus fruits in California is hand clipping the fruit stem flush with the fruit button. Increasing picking costs and large labor requirements of this operation have focused attention on the development of more economical methods of mechanical or hand removal.

This review of recent research data on application, effects and potential uses for antitranspirants in plant growth shows particular possibilities for conserving irrigation water, aiding plant survival under dry conditions, and protecting foliage against fungus, insects, smog, and salt spray. This information is not to be considered a recommendation of the University of California. Continued research is necessary to determine which materials offer the maximum reduction in transpiration with minimum reduction in photosynthesis, as well as optimum concentrations and application methods. A list of some antitranspirant materials (naming manufacturers and addresses) is available upon request to California Agriculture, Agricultural Publications, University Hall, University of California, Berkeley, California 94720.

Spider mites are the most destructive of the economic pests found on soybean plants in our hot interior valleys. Destructive species are the two-spotted mite, Tetranychus urticae K., and the Pacific mite, T. pacificus McG. High population densities of several hundred to over a thousand per leaflet may build up. The light to moderate white-stippled type of injury intensifies so that leaves turn yellowish, then brown, and drop prematurely. This causes a reduction of pod set and yield of seed. The studies have indicated that mite numbers should be kept at or below 4 to 6 per unit count to obtain any sort of satisfactory seed yield. After pod set commences, it appears necessary to have some type of mite control in or on the soybean plants or serious damage and seed loss will occur. Superior mite control has been obtained by chiseling a granular pesticide, such as Thimet, into the soil at planting time and again as a side-dressing in the seedling stage. Kelthane has afforded the best control of the foliage sprays tested. Trithion was fair but multiple sprays were needed. Pesticides discussed in this article have not been registered for use on soybeans and are not recommended for use at this time.

THE PINK BOLLWORM, Pectinophora gossypiella (Saunders) became a major pest of southern California cotton in 1965 and 1966. Since that time, one of the primary methods of controlling this insect has been the use of insecticide sprays. Spray treatments have usually been applied by aircraft at five- or six-day intervals beginning in late June or early July. Because of the protected habitat of the larvae, treatments have normally been directed against the adult moths.