California Agriculture, September-October 1983
Volume 37, Number 9
peer-reviewed research articles
Smog damage to cotton in the San Joaquin Valley
by Patrick J. Temple, O. Clifton Taylor, Larry A. Benoit, Chris A. Reagan, Robert W. Lennox
Not available – first paragraph follows: Photochemical air pollution (smog) is harmful to California agriculture, as has been widely recognized since the 1940s, when growers in the Los Angeles Basin reported silvering, bronzing, and other discolorations on leafy crops such as lettuce, spinach, and Swiss chard. Severe smog injury on these crops rendered the produce unmarketable or greatly reduced its value.
Evaluating the profitability of brush management and oak tree thinning for range improvement
by Kent D. Olson, Theodore E. Adams, Alfred H. Murphy
Not available – first paragraph follows: Clearing rangeland of dense brush thickets or stands of oak trees produces obvious benefits on the better soils: more and better feed for domestic and wild animals; improved water yield in the watershed; and reduced fire hazard. But there are also costs, which need to be weighed against potential returns before the decision is made to improve the land.
Sampling for California oakworm on landscape oaks
by W. Jan. A. Volney, Carlton S. Koehler, Lloyd E. Browne, Leslie W. Barclay, James E. Milstead, Vernard R. Lewis
A simple device to collect larval droppings indicates oakworm activity.
Growth control of Chinese elm with inhibitor sprays
by Henry Hield, Stuart Hemstreet
Not available – first paragraph follows: Spray applications of growth inhibitors to the foliage of ornamental plants have been known for many years to be effective. Sprays have been used to some extent, but possible hazards from spray drift to nontarget ornamental plants have led to the development of trunk banding and injection application techniques. However, foliar sprays, when safely used, are still the least expensive means of chemical growth reduction.
Pests in the home garden
by Carlton S. Koehler, Leslie W. Barclay, Thomas M. Kretchun
Many of the home remedies used to control garden pests may have merit but have not been scientifically tested. UC urban entomologists evaluated some of them under controlled conditions, with mixed results.
by Koehler, Barclay, Kretchun
They repel pests, but may also reduce garden crop yields.
by Koehler, Barclay
All except one barrier tested worked well.
Field bindweed in CaliforniaExtent and cost of infestation
by Sara S. Rosenthal
Not available – first paragraph follows: Field bindweed, or wild morning glory, probably originated in western Asia or the Mediterranean region and was accidentally transported along with agricultural crops wherever people migrated. It is now considered the world's 12th most important weed.
Field bindweed in CaliforniaThe outlook for biological control
by Sara S. Rosenthal, Lloyd A. Andres, Carl B. Huffaker
Not available – first paragraph follows: Biological control is seldom attempted against weeds on cultivated lands, because herbicides generally provide economical, efficient control, and farming practices may interfere with the biological agents. Field bindweed, however, reproduces from seeds that may remain alive in the soil for more than 40 years and from an extensive perennial root system. Control by cultivation or chemicals is difficult, at best. A search for biological control agents therefore seemed warranted. Even if such agents were effective only on field bindweed growing along roadsides and in other uncultivated areas, they would reduce the weed's potential for further invasion of cultivated land. A cooperative U.S. Department of Agriculture and University of California project was begun in 1970 to find biological agents for control of field bindweed.
Cultural control of navel orangeworm in almond orchards
by Curtis E. Engle, Martin M. Barnes
Not available – first paragraph follows: The navel orangeworm overwinters primarily in the larval stage in mummy almonds that remain in the trees or on the ground after harvest. In the spring, moths emerge and lay eggs on the mummy nuts in the trees, and these nuts provide the principal food source of the first-generation larvae. Moths of this generation emerge to infest the current year's almond crop during the hullsplit period. Infestations may reach as high as 30 to 50 percent.
Eucalyptus out-perform other species in salty, flooded soils
by Dean R. Donaldson, Janine K. Hasey, William B. Davis
Not available – first paragraph follows: Landscape plants are often needed for difficult sites. To find plants that would grow in saline, frequently flooded soils, we evaluated 106 species on a nonirri-gated floodplain underlain with salt water along the Napa River in northern California. The site was one of many established throughout the state for landscape tree evaluation.
Converting chaparral to grassland increases soil fertility
by Milton B. Jones, Robert L. Koenigs, Charles E. Vaughn, Alfred H. Murphy
Not available – first paragraph follows: Before Europeans arrived, the native Americans burned chaparral brush-lands to drive out wildlife in hunting, and to increase accessibility to the land. Now chaparral is often converted to grassland to help control wildfire, increase feed for livestock and wildlife, and increase water yield, as well as to improve accessibility. Reduced sheet erosion is often another benefit.
editorial, news, letters & science briefs
Agricultural research planning: A dilemma
by J. B. Kendrick