March-April 1995

Cover: Lady beetle preys on aphids on potted plants. Photo by Jack Kelly Clark

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California Agriculture, March-April 1995

Volume 49, Number 2
Lady bugs suppress aphids on potted plants

peer-reviewed research articles

Lady beetle release controls aphids on potted plants
by Mary Louise Flint , Steve H. Dreistadt , Jill Rentner , Michael P. Parrella
pp5-8, doi#10.3733/ca.v049n02p5
Abstract
Releases of convergent lady beetles collected in mountain aggregations significantly reduced aphid numbers on chrysanthemum and rose plants in pots. Preflying the beetles before release, or rearing them in a laboratory, did not clearly reduce dispersal. Because of their sensitivity to insecticides, care must be taken when releasing lady beetles into treated environments.
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How California agricultural producers manage risk
by Steven C. Blank , Jeffrey McDonald
pp9-12, doi#10.3733/ca.v049n02p9
Abstract
In a statewide survey, California agricultural producers ranked output price and input cost highest among their production and financial risks. Due to poor availability of hedging, forward contracting and crop insurance, less than 25% of the respondents used these tools to reduce risk. Diversification of production or income sources was their most common strategy for managing risk. Until risk tools are better tailored to the needs of California producers, and until producers become better informed about managing income risk, the state's agricultural sector will face unnecessarily high levels of financial stress.
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Vertical drainage may improve soil salinity and moisture
by Abdul Karim Yusufzai , Mark E. Grismer
pp12-15, doi#10.3733/ca.v049n02p12
Abstract
Existing drainage systems in many clay fields of the Imperial Valley have failed to improve soil salinity and to provide moisture conditions favorable to crop growth. In some fields, these problems are exacerbated by saline artesian water from a shallow sand aquifer. This pilot-scale field study in the Imperial Valley indicates that vertical drainage is more effective than traditional tile systems in reducing artesian water levels and the overlying clay soil moisture, and should over time also reduce the salinity of these soils. The cost of a widely spaced drainage well system appears comparable to “splitting” existing drainlines.
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Octenol fails to lure stable fly to insecticide
by Bradley A. Mullens , Nyles Peterson , Coralie E. Dada , Robert K. Velten
pp16-18, doi#10.3733/ca.v049n02p16
Abstract
A study was designed to determine whether blue targets were attractive to stable flies, whether octenol, a natural component of cow breath, enhanced attraction, and whether treating these targets with insecticide might enhance stable fly control. Blue cylindrical cloth targets treated with insecticides attracted resting stable flies in Southern California dairies. Octenol did not increase this attraction to the targets. Targets did not result in fewer flies in treated dairies, possibly due to insecticide resistance in these flies and the relatively small proportion of flies attracted.
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Vacuums provide limited Lygus control in strawberries
by Carolyn Pickel , Frank G. Zalom , Douglas B. Walsh , Norman C. Welch
pp19-22, doi#10.3733/ca.v049n02p19
Abstract
Lygus bug (Lygus hesperus) feeding causes small strawberry size and weight, but the most serious damage is a deformation of the fruit called “cat-facing.” Over two growing seasons, three grower-designed vacuum machines were evaluated for season-long control of Lygus bugs in production strawberry (var. ‘Selva’) fields on the coast. The Lygus bug control in fields vacuumed weekly and twice-weekly was compared to that in fields treated with malathion insecticide or an unregistered pesticide, bifenthrin. All vacuum machines significantly reduced Lygus bug damage when compared to the untreated control. However, the damage in plots treated only with the vacuum machines was high enough to be considered economically unacceptable.
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Integrated citrus thrips control reduces secondary pests
by Beth Grafton-Cardwell , Ashley Eller , Neil O'Connell
pp23-28, doi#10.3733/ca.v049n02p23
Abstract
Citrus growers are very concerned about scarring of the rind caused by early-season pests such as citrus thrips, katydid and various Lepidopterous larvae because heavily scarred fruit is downgraded in the packing house. Citrus growers who use a broad-spectrum pesticide program for early-season pests experience problems with pest resurgence and pesticide resistance, but generally have low levels of fruit scarring. Growers who use both selective pesticides and natural enemies have fewer secondary pest outbreaks of citrus red mite, but don't always effectively control citrus thrips scarring.
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Preschool children learn about ‘happy teeth’: Nutrition program boosts dental health of Orange County migrant families
by Anne Cotter , Margarita Cordovés , Joan Wright
pp28-32, doi#10.3733/ca.v049n02p28
Abstract
With dental disease one of the top health concerns of California's migrant families, it is imperative to provide these families with information promoting good dental health. In this pilot project, migrant children and parents attended a 7-week series of lessons to examine the effect of nutrition education on dental health-related behaviors. By the program's end, at least 30% of participating families had decreased consumption of foods considered harmful to children's teeth and had increased consumption of healthy foods, such as vegetables.
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Poor diet reflected in height, weight of low-income Hispanics
by Lorrene D. Ritchie , Doris H. Calloway , Suzanne P. Murphy , Olivier Receveur , Cathi L. Lamp , Joanne P. Ikeda
pp33-35, doi#10.3733/ca.v049n02p33
Abstract
A study of low-income Hispanic women and children in California revealed a high prevalence of individuals who were short in stature and overweight. Children in San Jose tended to be shorter than their Tulare County counterparts. Even after adjusting for socioeconomic variables and hereditary differences, the difference in size remained significant. These findings indicate that low-income Hispanics might benefit from nutrition and health interventions.
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Cultural practices improve color, size of ‘Crimson Seedless’
by Nick Dokoozlian , Don Luvisi , Mike Moriyama , Peggy Schrader
pp36-40, doi#10.3733/ca.v049n02p36
Abstract
‘Crimson Seedless’ is a lateseason table grape recently developed by scientists at the USDA-Agriculture Research Service. The cultivar holds significant promise for commercial producers due to its late maturity and seedless, crisp berries. Poor color and small berry size are the primary fruit quality problems associated with the cultivar. This study shows that trunk girdles applied at fruit set, combined with applications of the plant growth regulator ethephon, significantly improve the berry size, color and packable yield of this cultivar.
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editorial, news, letters & science briefs

EDITORIAL: Responding to the Challenges
by Kenneth R. Farrell
pp2, doi#10.3733/ca.v049n02p2
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Science Briefs
Editors
pp4, doi#10.3733/ca.v049n02p4
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