April 1975

Cover: Moth introduced for biological control of Russian thistle: (top) adult Coleophora parthenica, 12x; (lower left) egg of moth, 30x; (lower right) larva in stem of thistle, lox.

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California Agriculture, April 1975

Volume 29, Number 4

research articles

Biological control of russian thistle
by R. B. Hawkes , R. D. Goeden , A. Mayfield , D. W. Ricker
pp3-4, doi#10.3733/ca.v029n04p3
Abstract
Abstract Not Available – First paragraph follows: Russian thistle (Salsolu iberica Sennen and Pau), a plant native to Eurasia, has become a widespread weed in California and other western states. In these areas it serves as a favored alternate host plant for the beet leafhopper, Circlulifer tenellus (Baker), vector of the destructive “curly top” virus of such crops as sugar beets, tomatoes, and melons. The plant also harbors a variety of other insect pests such as lygus and stink bugs. These large, bushy “tumbleweeds” are common sights on neglected or abandoned croplands, vacant residential and industrial lands, and highway and railroad right of ways. The plants fracture at the base at maturity and scatter seeds as they are blown about by the wind. Tumbleweeds fill irrigation and drainage canals, pile up against fence and buildings, fill backyards and swimming pools, and startle motorists who encounter them while driving. Unsightly accumulations of the dead, dry plants are not only difficult to remove, but also create fire hazards and traps for other windblown debris.
Expanded Abstract | PDF

Food system coordination
by Leon Garoyan
pp4-6, doi#10.3733/ca.v029n04p4
Abstract
Abstract Not Available – First paragraph follows: Investments in the U.S. food and fiber system from production through final sales are so large that few of the individuals and firms comprising it can afford to leave their destiny to chance or individual whims. Large-scale retailers and food service firms require consistent supplies at predictably uniform prices, as do the food manufacturing firms that supply them. Moreover, individual farmers with large capital investments cannot gamble on future market outlets.
Expanded Abstract | PDF

Urbanization and streamflow in the Berkeley hills
by Joe R. McBride
pp6-7, doi#10.3733/ca.v029n04p6
Abstract
Land use around the larger cities in California has changed as agriculture has given way to urbanization. From 1950 to 1970 this change was especially rapid in the Berkeley hills, which lie to the east of San Francisco Bay. Streamflow characteristics in the hills have changed significantly as a result. Since knowledge of these changes is important for responsible water planning and aquatic wildlife management, this report summarizes the results of a preliminary study of the impact of urbanization on periodicity of streamflow.
Expanded Abstract | PDF

Effect of additive on corn and oat silage preservation
by W. B. Hight , D. L. Bath , W. R. Sheesley , Darrel Miller
pp8-9, doi#10.3733/ca.v029n04p8
Abstract
Trials conducted in Madera County with corn silage and oat and vetch silage indicated that treatment with a popular silage additive resulted in no discernable differences between treated and untreated silages. The silages were analyzed for pH (acidity) and percentage of dry matter, crude protein, crude fiber, ether extract and ash. In addition, observation of the treated and untreated silages revealed no differences in color, odor, amount of seepage, and cow acceptance.
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Sealing bunker silos: Effect on silage losses
by W. B. Hight , D. L. Bath , Darrel Miller
pp10-12, doi#10.3733/ca.v029n04p10
Abstract
Trials were conducted in Madera County to test the effect of covering and sealing bunker silos filled with either corn or oat silages. Lower temperatures within the silage mass and a considerable increase in preserved silage resulted from covering and sealing the silos with 6 mil black polyethylene.
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Wax and meal changes in jojoba seed development
by Demetrios M. Yermanos
pp12-13, doi#10.3733/ca.v029n04p12
Abstract
Wax content of jojoba seed increased rapidly from the first to the fourth week. Protein content of jojoba meal increased at a slow, steady rate during the entire period. Seed harvested 20 days prior to full maturity had essentially the same wax and protein content as mature seed, but it had lower dry seed weightand excessively high moisture content.
Expanded Abstract | PDF

Lesion nematode control in apples
by R. Rackham , J. D. Radewald , C. L. Hemstreet , F. Shibuya
pp14-15, doi#10.3733/ca.v029n04p14
Abstract
Abstract Not Available – First paragraph follows: Lesion nematodes (Pratylenchus sp.) are recognized as pathogens of apples in the eastern part of the United States, and various preplant control measures have been demonstrated beneficial in re-establishing orchards. During the early ′60s two small-scale preplant fumigation trials were conducted in replanted orchards in the Oak Glen area of San Bernardino County, California. Many tree replants or interplants in established orchards in this area were dying or demonstrating lack of vigor at that time. Soil and root analysis showed that high populations of Pratylenchus sp. were present in the orchards and were believed to be a major contributing factor to tree failure in these orchards. The results of these two early trials showed that preplant measures for nematode control were beneficial.
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Root-knot nematode control in cantaloupe
by J. D. Radewald , D. G. Kontaxis , F. Shibuya
pp15-16, doi#10.3733/ca.v029n04p15
Abstract
Abstract Not Available – First paragraph follows: Cantaloupe is grown on a wide variety of irrigated soils in southern California. Of the root-knot nematodes, Meloidogyne incognita, is the most common species which attacks this crop. This nematode, as well as other species of the genus, is generally a problem on coarsertextured soils in the southern valleys. When M. incognita is present at planting time it stunts the young plants soon after emergence and causes severe galling of the roots (photo). Plants infected in the very early stages of growth remain stunted and unproductive and seldom bear marketable melons (photo). Localized infestations in a field range in size from a few square yards up to several acres. Sometimes entire fields are uniformly infested with the nematode and, if proper preplant control measures are not taken, the entire field may be unproductive.
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Surface runoff in dairies
by A. C. Chang , K. Aref , D. C. Baier
pp16-17, doi#10.3733/ca.v029n04p16
Abstract
Hydrologic analysis indicated that surface runoff from manure accumulated in dairy areas would not occur very frequently in southern California. This was verified by a field test using simulated rainfall. Hydrologic data collected in this experiment were used to establish the runoff-rainfall relationship for the Chino-Corona dairy preserve. Though the amount of runoff may not be large, the high mineral and organic carbon contents of manured runoff is detrimental to the water quality of receiving streams. The high salinity and low nutrient content would make its possible beneficial use on cropland seem doubtful. In wet years, the disposal of salt-laden wastewater could become a problem. Holding ponds and retention structures for surface runoff merely prevent it temporarily from entering the receiving water.
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Sunburn protection for newly-grafted Payne walnuts
by G. S. Sibbett , M. Bailey
pp18, doi#10.3733/ca.v029n04p18
Abstract
Abstract Not Available – First paragraph follows: Because scions and rootstocks are sensitive to heat, they sunburn readily following grafting. When walnut rootstock is grafted, either the year planted or the following year, ordinary whitewash or a 50% solution of interior latex paint and water have commonly been applied for sunburn protection. In orchards where these sunburn treatments have been applied, erratic growth and poor grafting frequently occur, suggesting the whitewash treatment might be responsible. The experiment reported here was conducted to determine the influence of a sunburn protection treatment on growth of newly grafted trees.
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editorial, news, letters & science briefs

EDITORIAL: Is the cow a white elephant?
by J. B. Kendrick
pp2, doi#10.3733/ca.v029n04p2
PDF