All Issues

Declining root systems comprise one of the most serious problems in southern California in citrus production and fruit size. Therefore, a station-wide citrus rejuvenation project was initiated in 1953.

The use of 2,4-D and related compounds to control weeds competing with grain and rice has resulted in an increased value of those crops to growers; but also it has resulted in damage suits filed by growers of crops susceptible to 2,4-D—cotton, grapes, tomatoes, and others—grown near rice or grain fields.

The value of 2,4-D and related substances for preventing mature citrus fruit drop, for increasing fruit size, and for amending oil spray used for pest control to prevent leaf drop or fruit drop—or both—has been demonstrated.

The effectiveness of all frost protection depends primarily on the temperature inversion—ceiling—but adequate measurements had not been made until an extensive field program was undertaken in northern California in the spring of 1956. Six thermographs equipped with 50' extensions were installed with other spot-climate recording stations in selected deciduous orchards. Several growers contributed to the project by keeping the thermographs in operation.

Field observations—and controlled fumigation experiments—have shown that plants differ in their response to atmospheric contamination by ethylene, herbicides, fluorides, sulfur dioxide, and smog, or oxidized hydrocarbons.

The date palm is a one seed-leaf— monocotyledonous—plant, and stock to be used for orchard plantings is usually obtained as offshoots from the parent palm.

Vines develop abnormal growth if they bud out early following midwinter pruning—in certain vineyards in southern California—apparently because of insufficient boron at time of budding out.

Suspected resistance to DDD and DDT in controlling caterpillars attacking tomatoes—the corn earworm, in particular—was investigated in San Joaquín County during the 1955 season.