Calag Archive

Profitable citrus growing in the San Joaquin Valley involves successful risk analysis and the offsetting of perils resulting from overproduction, competition, frost, diseases and insect pests. Marketing difficulties are usually resolved through cooperative effort. Overcoming production risks requires problem-solving procedures applied to each orchard and crop.

Photos show methods used to determine cotton variety impact on lygus bugs: top left, whole plant; lower left, terminal sleeve; top right, leaf bouquet cages used to determine egg laying preferences; lower right, detached squares and fruit jar cage used to determine cotton variety impact on bug growth.

This report describes the establishment of a long-term, field-scale nitrogen tracing experiment for fertilizer-nitrogen at the Kearney Field Station, Parlier. The isotopic 14-nitrogen (obtained from Los Alamos through the cooperation of the U. S. Atomic Energy Commission) has been found to be an effective, practical fertilizer-nitrogen tracer—and is expected to be of particular value in future experiments toward understanding the cycling of nitrogen through the environment.

Weather conditions following bait treatments for the control of the European brown garden snail in citrus groves substantially influenced the ultimate effectiveness of carbamate molluscicides. Baits containing Mesurol were more effective under unfavorable conditions than the other carbamates used in the tests. Under optimum treatment conditions, all of the carbamate baits were effective, particularly those with metaldehyde inclusions.

The citrus stubborn disease organism, Spiroplasma citri, has been cultured from beet leafhoppers collected from citrus near Riverside. This leafhopper is commonly a vector of curly top virus of sugar beets and other plants and is periodically abundant in hot, dry areas where sugar beets, citrus, and many other hosts are grown. This is the first report of a natural insect carrier of the citrus stubborn organism and is believed to be the first recorded instance of culturing a naturally acquired mycoplasma-like organism from an insect carrier.