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The mass of silage stored in bunker silos should not be considered homogeneous. The variation between layers of silage may be caused by climatic variations during filling and storage, variations in mechanical packing intensity during filling, variations in the maturity of corn silage brought to the silo, and the lack of an effective airtight, moisture-proof cover. Rain falling during the winter months of 1967 on an uncovered bunker silo in Glenn County greatly increased the moisture content of the upper 4 ft of silage and leached soluble nutrients into the lower layers and possibly out of the silage mass. The TDN content of the upper 2 ft was significantly reduced. Dry matter losses, representing loss in weight of silage, were severe in the upper 4 ft of the silage mass, with greatest losses occurring in the upper foot. Dry matter loss was less severe in the entire silage mass, but averaged 18.8 per cent of the dry weight of the original samples placed throughout the silo. The percentage of crude protein, crude fiber and ash apparently increases while the nitrogen-free extract component decreases in the upper layers of the silo, possibly due to leaching. However, in reality, the most severe loss in nutrients, and dry matter, in the entire silage mass resulted from surface spoilage through continued exposure to air, involving fermentation, and respiration by spoilage microorganisms. Covering a bunker silo with plastic did reduce losses of dry matter to less than 10 per cent in the 1965 and 1966 studies.

SUCCESSFUL HARVESTING with mechanical shakers requires a tree with an open-spreading branch structure. A vase-like arrangement of three primary scaffold branches arising from the main trunk at a height of from 24 to 30 inches is ideal. The low, open-centered, spreading canopy thus formed allows fruit to fall to a catching frame with less chance of striking interfering branches.

The walnut aphid, Chromaphis juglandicola Kaltenbach, is an Old World species which apparently invaded California at about the turn of the present century. Although attacked by native lady beetles, green lacewings, and other natural enemies, the aphid frequently becomes extremely abundant. Consequently, walnut growers in many areas routinely treat their groves with insecticides to control it. For years, nicotine sulfate was the most widely used aphicide, but since the middle 1940's it has been supplanted by a variety of synthetic organophosphates and chlorinated hydrocarbons.

A number OF new chemical sprays were tested for frost protection of young citrus during the winter of 1969-70. Fifteen commercial compounds were sprayed on container-grown grapefruit nursery trees and young lemon trees in the field. Most of the compounds were antitranspirants (film-forming, stomata closing, and reflecting types). Growth inhibitors used were maleic hydrazide (MH), potassium salt of 6-hydroxy-3-(2H)-pyridacinone (KMH), and ethyl hydrogen 1-prophylphosphonate (NIA-10637). Freezing the grapefruit nursery trees in a cold chamber resulted in no significant differences in the amount of cold protection given by any of the sprays. Temperatures in the field where the young lemon trial was located never reached freezing, but there were significant differences in growth response to the different sprays.

THE NEAT ROWS OF WHITE AND PINK blooming trees in the San Joaquin and Sacramento valleys will have a new look this spring. Strips of brown soil bordered by green interspaces may be seen down many of the tree rows. These weed-free strips will probably be the result of herbicides applied before the rainy season and prior to weed emergence.

ONE OF THE SERIOUS PROBLEMS in the production of pot-grown lilies for the Easter season involves root and bulb rots. Fungi which have been associated with this problem include Cylindrocarpon radicicola, Fusarium oxyspofum f. lilii, Pythium splendens and Rhizoctonia solani. Because of the different fungi involved, fungicide mixtures have been recommended for control, the most common ones mixtures of pentachloronitrobenzene (PCNB) and ferbam or PCNB and Dexon. Disease control was not always good, or consistent, so new materials have been tested as they became available.