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January-February 1990

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California Agriculture, January-February 1990

Volume 44, Number 1

Peer-reviewed Research and Review Articles

Biological control sought for ash whitefly
by Tom S. Bellows, Timothy D. Paine, Ken Y. Arakawa, Carol Meisenbacher, Paula Leddy, John Kabashima
Ash whitefly has spread over a large portion of California since the initial infestation was discovered in Los Angeles County in 1988. Populations have grown to high densities on a wide range of host plants, including ash, pear, apple, citrus, and other landscape and fruit trees. The best hope for control appears to be natural enemies: a parasitic wasp and a predatory beetle have been introduced and are being evaluated.
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Harvesting eucalyptus for fuel chips
by Bruce R. Hartsough, Gary Nakamura
Six-year-old eucalyptus trees were harvested, chipped, and delivered to an electric power plant. Costs exceeded the value of the chips. Expenses could be reduced if bigger trees were harvested, more acres were cut, and the stand were closer to the power plant.
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Distribution of peach twig borer damage in peaches
by Craig V. Weakley, Philipp Kirsch, Frank G. Zalorn
Damage to fruit by the peach twig borer was greatest late in the season and in the tops of trees at the orchard edges. Monitoring for damage should begin at least 4 weeks before harvest.
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Walnut dehydrators vary in performance
by Joseph A. Grant, James F. Thompson
Samples from 11 walnut dehydrators in San Joaquin County showed substantial over drying. Using grain moisture meters helps, but more accurate, faster methods are needed to test moisture of nuts throughout the bin.
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Sweet sorghum cuItivars for alcohol production
by F.J. Hills, R. T. Lewellen, I.O. Skoyen
Sweet sorghum does well in much of California. Cultivars were tested that showed a potential for producing from 475 to 575 gallons of ethanol per acre.
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Clogging of buried drip irrigation systems
by Larry J. Schwankl, Terry L. Prichard
Lime precipitate clogging of buried drip irrigation systems is difficult to detect and can cause problems where water quality is poor. Injecting a phosphonate was as effective as acid against clogging in two field trials, and may cost less.
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Treatment timing defined for Egyptian alfalfa weevil in the high desert
by Vernon M. Stern, Steve B. Orloff
Profits were highest in Mojave Desert alfalfa when treatment for Egyptian alfalfa weevil was applied soon after winter plant regrowth began and leaf damage was present on new stems.
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Parasitoid helps control fruit worm in Sacramento Valley processing tomatoes
by Michael P. Hoffmann, Lloyd T. Wilson, Frank G. Zalom, Richard J. Hilton, Craig V. Weakley
Naturally occurring populations of the parasitic wasp Trichogramma help control the tomato fruit worm in processing tomatoes grown in the Sacramento Valley. Incorporating this factor into the pest management decision-making process should reduce insecticide applications needed to control the pest.
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Immigration reform and California agriculture a year later
by Philip L. Martin, J. Edward Taylor
A February 1989 survey indicated the 1986 law had not yet affected crop production, wages, or employment.
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Stable fly and house fly breeding sites on dairies
by Jeffery A. Meyer, Thomas A. Shultz
Variations in management practices on dairies in central and southern California have resulted in some differences in fly breeding sites. Sanitation will have to be a focus of fly control efforts in the future on all dairies.
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Cultural management of bluetongue virus vectors
by Bradley A. Mullens, John L. Rodriguez
Surveys and experiments in dairy wastewater ponds showed that pond design and management affect populations of blood-feeding gnats that spread bluetongue virus. A voiding shallow evaporation beds, changing water levels weekly, and keeping manure pollution below 300 to 400 milligrams COD per liter will help control gnats.
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Editorial, News, Letters and Science Briefs

EDITORIAL: Meeting challenges of the 1990s in agriculture and natural resources
by Kenneth R. Farrell
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