All Issues

Tree fruits are usually propagated by budding or grafting on seedling root-stocks but such seedlings tend to show more or less variability in many characteristics, including resistance to nematodes and diseases.

Spraying drained rice fields for weed control is a recent development although the spraying of flooded rice by airplane is an established and steadily increasing practice.

Laboratory rice drying studies conducted during the fall of 1956 investigated the effect of drying-air temperature and relative humidity on the quality of the milled rice. At the same time, a study was made of the possibility of drying with a one-pass column-drier using high relative humidities.

Ammonium-form fertilizers have special significance in the production of the California rice crop because ammonium nitrogen is the only inorganic form that can be maintained in continuously flooded soils. However, the maintenance of ammonium nitrogen is dependent upon proper fertilizer placement. When ammonium nitrogen is placed at a depth of 2″-4″ in a rice seedbed prior to flooding, its maximum utilization for increased rice yields is realized. Nitrogen which is converted to nitrate nitrogen before or after flooding will be denitrified and lost from the soil as nitrogen gas.

The artichoke plume moth—Platyptilia carduidactyla (Riley)—caused crop losses as high as 90% during 1956 and is the most important restricting factor in the production of artichokes.

Producing artichokes in the Half Moon Bay area during the 1956-57 season cost $513.36 per acre—$2.20 per 22-pound box—according to information obtained in a recent survey.

Three imported wasp species—parasites of the spotted alfalfa aphid—have survived their first winter in southern California alfalfa fields and have become abundant in several localities.

Summer walnuts infested with the codling moth furnish breeding locations for the navel orangeworm and—as a result—a population of moths is present in the orchard when the husks begin to crack as the harvest period approaches. The caterpillars of the navel orangeworm are unable to penetrate the green husks of sound walnuts so they are not subject to infestation until maturity is reached and the husks split. After this stage of nut development is reached, the crop is open to attack until it is harvested. As a result the amount of infestation tends to increase as harvest is delayed.

To determine the effects—if any—on the juice quality and fruit yield of pest control oil spray applied to lemon trees in any of the months from August through January, experimental blocks were established in two widely separated orchards.