All Issues

A small leaf-mining agromyzid fly of omnivorous tastes—Liriomyza langei Frick—caused a 50% loss to fall spinach in the Salinas Valley in 1956. The unofficial allowable tolerance for larvae could not be met in many instances with as many as six weekly applications of combination phosphate and chlorinated hydrocarbon insecticides at a total cost of $60 an acre.

Carnation growers in California—constantly combating spider mites, thrips and aphids, and occasional infestations of carnation bud moth or mealy-bugs—have two new pests to fight.

An increasing number of reports of codling moth resistance to DDT—although none of the cases occurred in California—prompted the testing of several new materials for codling moth control during the 1956 season.

Destructive populations of soft scales—frosted scale, Lecanium pruinosum, Coq.; European fruit lecanium, L. corni Bouché: and the calico scale, L. cera-sorum Ckll.—occurred on walnuts in many locations in northern California during 1956.

Growth of Zutano avocado seedlings was reduced when the plants were exposed to synthetic smog—a mixture of ozone and hexene vapor—in an experiment designed to study the effect of the toxicants on seedling growth.

Deficiencies of many of the minor nutrient elements in most species of fruit trees can be corrected by sprays.

Differences in the surface 6′ of soil—in structure, color, texture, reaction, content of salts or humus, mineralogical composition—usually have agricultural significance and separate soils into different series or identifying units of classification. Nearly 500 soil series have been identified in California.

Soil may be sterilized easily by an electron beam—of sufficient intensity and energy—without destroying the urease-enzyme activity.

Long-time studies of Satsuma mandarin nucellar-seedling lines—derived mainly from a single seed-parent tree—indicate that both genetic change and nucellar embryony may be responsible for earlier fruit coloring, especially in heavy-crop years, and for a consistently higher per cent of soluble solids than in the old parent line.