All Issues

A report of progress in the development of alfalfa resistant to the spotted alfalfa aphid conducted in cooperation with the Entomology Research Branch, Agricultural Research Service, U.S.D.A.

The false spicier mite—Brevipalpus lewisi McGregor—first became a potential pest of walnut in the 1955 season although it has been known in California since 1944.

A system of orchard appraisal mapping successfully used in an extensive survey of California orange orchards records in detail the specific causes of poor tree health and production.

Symptoms of plant damage in the field can often be identified as the effect of one or more air pollutants. However, the exact mechanisms whereby the plant is damaged and the various manifestations of damage—after fumigation with air toxicants—are not so well known.

Natural causes—starvation, accidents, internal parasites, diseases, and predation—accounted for 47% of the losses observed in a population of Columbian black-tailed deer, studied on the Hopland Field Station of the University of California.

Radioactive tracers were used in a test at Davis—involving four animal barns— to determine the feasibility of identifying a source of a fly nuisance by means of radioisotopes.

Loss of leaves in olive trees decreases the number of perfect flowers and therefore may lower production since imperfect flowers cannot set fruit.

Califlay, a new variety of spinach that is completely immune from downy mildew—blue mold—has been planted in most of the spinach-growing areas of the state during the past two years and growth appears to be satisfactory in all areas.