January-February 1992

Cover: Registered by a satellite sensor 35,000 kilometers above Earth, the red tones of the infrared image on the cover indicate reflectance by green, photosynthesizing plants. Such satellite images can be used to generate maps of vegetative cover, using a Normalized Difference Vegetation Index (NDVI). NDVI images help track and predict the spread of exotic pests. Photo and computer image courtesy of NASA AMes Research Center.

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California Agriculture, January-February 1992

Volume 46, Number 1
Invasion forecast: the exotic pest threat

peer-reviewed research articles

On the California border, exotic pests pose growing problem for California
by Robert V. Dowell , Conrad J. Krass
pp6-12, doi#10.3733/ca.v046n01p6
Abstract
Major pest threats are profiled, as are the CDFA's exclusion and eradication efforts.
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Plant quarantines: domestic strategies yield to international policies
by Dorthea Zadig
pp9-10, doi#10.3733/ca.v046n01p9
Abstract
Since 1875, quarantine laws have been enacted to protect domestic agriculture from foreign pests. Today, thanks to efficient agricultural production and swift commodity transport, California growers have access to widespread international markets. Domestic regulatory policies are no longer adequate and must yield to new and developing international regulatory policies. The General Agreement on Tariffs and Trade (GATT) is considering an initiative to harmonize plant quarantine regulations among nations. In addition, development of the “pest-free” zone concept has benefited both exporters and importers.
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The Mediterranean fruit fly in California: taking stock
by James R. Carey
pp12-17, doi#10.3733/ca.v046n01p12
Abstract
Medflies have been captured in California 11 different years since 1975, and every year since 1986. Ten eradication programs have been mounted against this pest at a cost of over $150 million. While considerable scientific debate still exists on the nature of the medfly problem in the state, most agriculturalists agree that the problem is probably long-term. This paper provides a brief historical background of the medfly in the state, reviews existing control technologies and outlines future research needs and directions.
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How Africanized honey bees will affect California agriculture
by Robert E. Page
pp18-19, doi#10.3733/ca.v046n01p18
Abstract
Africanized honey bees are expected to invade Southern California within the next 3 years. How far they will spread and how they will affect the agriculture of this state are of great concern. This article discusses the origins, current status and expected impact of Africanized bees on California agriculture.
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Ecological research: Long-term studies to gauge effects of invading bees
by Robbin W. Thorp , Gordon W. Frankie , John Barthell , David Gordon , Linda Newstrom , Terry Griswold , Justin Schmidt , Steve Thoenes
pp20-23, doi#10.3733/ca.v046n01p20
Abstract
The expected invasion of the United States by Africanized honey bees has inspired long-term studies documenting the ecological importance of native and introduced bees. Baseline data are being gathered to predict the effects of the invasion. Standardized sampling procedures and tools have been developed to monitor bee communities. The studies will provide information for developing wildland area conservation policies.
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Biological control of ash whitefly: a success in progress
by Tom S. Bellows , Timothy D. Paine , Juli R. Gould , Larry G. Bezark , Joe C. Ball , Walt Bentley , Richard Coviello , Jim Downer , Pam Elam , Don Flaherty , Patty Gouveia , Carl Koehler , Richard Molinar , Neil O'Connell , Ed Perry , Greg Vogel
pp24-28, doi#10.3733/ca.v046n01p24
Abstract
Two natural enemies of ash whitefly (Siphoninus phillyreae), jntroduced into California in 1990, proved effective in Southern California field trials, completely controlling this Dest in release sites within -24 months, Evaluations in release sites in Central and Northern California, Arizona and Nevada look equally promising.
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Sweetpotato whitefly: prospects for biological control
by Michael P. Parrelta , Tom S. Bellows , Raymond J. Gill , Judith K. Brown , Kevin M. Heinz
pp25-26, doi#10.3733/ca.v046n01p25
Abstract
The damage to desert agricultural crops in Southern California and Arizona in fall-winter 1991 by the sweetpotato whitefly, Bemisia tabaci (Gennadius) is unprecedented in the history of the South west. Damage estimates exceed $200 million for California alone with the complete loss of the fall and winter melon crop and major damage to many winter vegetables and other crops. Origins of the problem, and potential biological control agents, are discussed.
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Imported fire ants: potential risk to California
by Vernard R. Lewis , Laura D. Merrill , Thomas H. Atkinson , Joanne S. Wasbauer
pp29-31, doi#10.3733/ca.v046n01p29
Abstract
Since the first general detection surveys for imported fire ants in California in 1987, 758 intercepts among the state's 16 border inspection stations have been recorded. One colony discovered at a nursery in Santa Barbara in 1988 was successfully eradicated. With more traffic expected into California, it is likely that interceptions and localized eradication efforts for imported fire ants will increase.
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Russian wheat aphid: natural enemies, resistant wheat offer potential control
by D. González , Charles G. Summers , Calvin O. Qualset
pp32-34, doi#10.3733/ca.v046n01p32
Abstract
A severe pest of small grains, Russian wheat aphid has been spreading throughout all of California's cereal-growing regions for nearly 4 wears. Coordinated research to develop economically and environmentally acceptable management strategies for this pest is in progress.
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“Organizational classes” explain differences among westside farms
by Mark B. Campbell , Ariel A. Dinar
pp35-39, doi#10.3733/ca.v046n01p35
Abstract
Since the advent of industrialization, social theorists have been analyzing the complex relationships of industrial systems. At the same time, attention to agricultural production systems has waned. The fact that agricultural systems resemble early industrial systems suggests that farms might be studied using the same theories as those applied to industrial organization. That is, farms can be organized according to how they function. Farms which function similarly are said to belong to “organizational classes”. Types or classes of farms perform differently in the ease with which they can adopt to new technology or apply intensive agricultural practices. We used two organizational variables — task specialization and configuration — to distinguish among farm types on the westside of the San Joaquin Valley. Five organization types were defined and found to be significantly different with regard to several production variables including number of full-time and part-time workers, acres farmed and use of computers.
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editorial, news, letters & science briefs

EDITORIAL: Exotic pest research well worth the price
by Kenneth R. Farrell
pp2, doi#10.3733/ca.v046n01p2
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UC develops expanded agenda to combat exotic pests
by James M. Lyons
pp5, doi#10.3733/ca.v046n01p5
Abstract
UC has recently established the Center for Pest Management Research and Extension.
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1991 Index
Editors
pp39-40, doi#10.3733/ca.v046n01p39
Abstract
Following are articles appearing in California Agriculture, Volume 45, Numbers 1 through 6, January through December 1991. Back issues may be purchased, while supplies last, at $2.00 per copy (make checks payable to UC Regents).
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