Calag Archive

Rapida, a new oat variety, features quicker development than any other normally winter-sown feed grain (barley, oats, wheat or rye). Considered more a “new crop” than a new variety, Rapida came from a double hybridization of a cultivated oat variety with the wild oat, Avena fatua L. In the Davis area, it has been planted July 1 and harvested (mature grain) early in September—suggesting the possibility of growing three successive crops in some parts of California.

Whitewash applied to the leaves of Persian walnut trees of the Payne variety showed no injury to the leaf and did not interfere with photosynthesis. There was no significant effect on total yield in the whitewash tests, but the percentage of larger, sound nuts increased. These studies also indicated that temperatures above 90°F were very detrimental to photosynthesis and temperatures of 95°F or above stopped it completely.

Cotton yields have progressively decreased in many fields in Tulare and Kings counties in the San Joaquin Valley since 1960. Losses have been attributed to new races of Verticillium albo-atrum, potassium deficiency, and a change in tolerance to Verticillium wilt in the Acala 4-42 variety (grown exclusively in the San Joaquin Valley since 1954 because of its wilt-resistance).

A saving in both seeding and thinning costs can be obtained from precision planting of tomatoes to be harvested for canning. To make precision planting effective, other cultural practices also must be more precise - including a sufficient amount of surface moisture (to minimize crusting) and an absence of weeds

Pre-emergence herbicides such as simazine and diuron (Karmex) are widely used for annual weed control in commercial apple and pear producing areas outside California. A 1964-65 survey of California orchards showed that very few acres of apples and only about 1000 acres of pears were sprayed for annual-weed control during that winter. Both simazine and diuron have been registered for use in apples and pears by the state of California and USDA. New developments in orchard culture, including hedge-row planting of pears, together with the scarcity of hand labor, have resulted in a recent upsurge of interest on the part of California orchardists.

Powdery mildew can reduce yield and quality of cantaloupes in the arid inland valleys of California. The plants are defoliated, particularly around the crown of the plant. Thus the fruits become sunburned, ripen prematurely, and are lacking in soluble solids, and in general have poor edibility. The ratio of culls to marketable fruit increases tremendously. Powdery mildew is caused by the fungus, Erysiphe cichoracearum.

Very good control of aphids in barley was obtained with commercial-scale airplane applications as low as 5 Ibs of 10% Thimet granules (1/2 Ib actual toxicant) per acre. However, problems with hopper calibration, and the extreme accuracy in flying necessary to apply this low rate of the systemic insecticide, make a 71/2- to 10-lb rate of application more realistic. Chemical control of aphids on barley was found economical only when populations averaged significantly higher than 25 to 30 aphids per tiller. In seven southern California barley fields treated with Thimet granules (at 1 Ib of actual material per acre) the mean yield increase was 434 ± 128 Ibs per acre. Even at the lowest increase (306 Ibs per acre) the value of the extra yield was well above the cost of aphid control. The average aphid population in the check plots rose to 39 per tiller.