Calag Archive

Solid fuel, candle-type heaters have been tested to determine their effectiveness when used, both under trees and in the open, to protect against freezing damage in a citrus orchard. Two heaters under each tree were found effective in increasing fruit temperatures under the tree by about 3°F, and heaters both under the tree and outside the tree more than doubled the temperature rise. Heaters placed outside the tree were less than half as effective as those under the tree in increasing fruit temperature—either for fruit inside the tree or for exposed fruit on the outside of the tree.

Cotton lint yields of Acala 4–42, Deltapine Smooth Leaf, and Strain A decreased as planting was delayed after March 22, but an earlier planting (March 8) did not increase yields in tests at the Imperial Valley Field Station in 1962 and 1963. Gin turnout (expressed as percentage of lint) of Acala 4-42 increased slightly as planting was delayed, but decreased in Strain A and DPL-SL. There seems to be no advantage in planting cotton before March 20 in the southern part of Imperial Valley. The advancement of pink bollworm infestations in Arizona and Bard Valley, California, puts further emphasis on planting dates for help in control of this pest.

Coachella Valley Thompson Seedless grape growers have been applying a gibberellin spray to the fruit soon after bloom to increase berry size. Test plot work in previous years has shown that a variation of timing of this application by as little as a week can produce important effects on berry size, fruit maturity, shape of the berry, and density of the cluster. Better results have been obtained with two applications than were achieved with only one. Such tests in previous years have been made on commercial vineyards where the grower thinned and girdled at the time he thought best. This study was conducted to evaluate the effect of the timing of any one of these operations upon the results obtained from any other.

Certain parameters must be established if citrus harvesting devices are to be designed and used effectively. For this reason the relationships between a citrus tree and a man-positioning device were analyzed in this study in terms of the tree shape, the motions of the machine, and the motions of the operator of the machine. For this discussion, the tree is considered a cylindrical body (when ideally pruned) and the position of any point on its surface or within its boundaries is determined by the "cylindrical curvilinear coordinate system." The coordinates are defined as follows: r = the length of the radius; È = the angular direction of the radial coordinate relative to an arbitrarily selected radial line. The height above ground is the third coordinate, which is designated by Z, and it determines the position of the point relative to the base of the cylinder (fig. 1).

These studies suggest that when trifluralin is applied as a directed spray in commercial cotton fields, care should be exercised to avoid spraying the herbicide on the terminal or lateral buds. In fields where the cotton plants vary in size, it may be advisable to delay directed-spray application to avoid plant injury.

WHETHER IT IS CALLED oak root fungus, shoestring fungus, or mushroom root rot fungus, Armillaria mellea in soils can be destructive in orchards, vineyards, and home gardens. The fungus attacks over 600 species of plants and though it usually attacks woody plants, it may also attack certain herbaceous plants including dahlia, rhubarb, potato, and strawberry. Armillaria is found throughout the world in temperate and mild-temperate zones, and is considered to be native to California where it attacks root systems of many plants, but especially the native oaks. Such plants, though frequently infected, are not often killed by the fungus unless they receive summer irrigation or the soil level around them is changed. Following either of these conditions, they may die, and Armillaria is frequently a contributing factor. Even more important is the fact that, when infected trees are removed and some or all of the root system is left in the soil, the fungus will move rapidly through the dead root systems thus creating a reservoir from which the fungus can later attack nearby plants, or young orchard trees set out at such sites. Such plants are frequently susceptible and may be killed rapidly.

Air transit is greatly reducing the marketing period for much of California's strawberry crop. However, low holding temperatures were still found important for strawberries—even when they are consumed within two or three days of harvest. Constant low holding temperatures provided the greatest protection, and any warming was detrimental to fruit quality. Total deterioration was related to the total length of time fruit was exposed to warm temperatures, regardless of the pattern of exposure. Rewarming of fruit after cooling did not accelerate the rate of deterioration, as compared with fruit held at a constant warm temperature.

Dodder causes sufficient agricultural losses to be considered a noxious weed in many states. Seed certification regulations help to restrict the spread of this prolific seed producer, but it is very difficult to clean out of many small-seeded crops. Once dodder has infested a seed production area, susceptible crops may be limited for several years since many species of dodder may infest more than one host.