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January-March 2008

Cover: California's $45 billion wine industry continues to grow and change. In Sonoma County's Alexander Valley (shown), vineyards continue to expand, as do premium wine-growing areas along the coast. Photo: ©2008 Herb Lingl (aerialarchives.com)

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California Agriculture, January-March 2008

Volume 62, Number 1
Better wines, more vines: California and the world wine revolution

Peer-reviewed Research Articles

California wine industry evolving to compete in 21st century
by Rachael Goodhue, Richard Green, Dale Heien, Philip Martin
pp12-18, doi#10.3733/ca.v062n01p12
Abstract
The California wine industry is growing and changing amidst a global revolution in grape growing, wine production, wine marketing and consumer tastes. California accounted for roughly 90% of the value of U.S. wine production in 2006. U.S. per capita wine consumption and the quality of wine consumed continue to rise. The largest California wineries have long accounted for most California wine shipments and continue to expand with respect to volume and number of labels. While small wineries sell most of their wine directly to end-users, many midsized wineries face challenges in an increasingly crowded marketplace.
Expanded Abstract | HTML w/Links | PDF

Post-emergence herbicides are cost effective for vineyard floor management on the Central Coast
by Laura Tourte, Richard Smith, Larry Bettiga, Tiffany Bensen, Jason Smith, Daryl Salm
pp19-23, doi#10.3733/ca.v062n01p19
Abstract
Central Coast growers are under increasing scrutiny and regulatory pressure to manage herbicide use because of their farmland's proximity to the Monterey Bay and National Marine Sanctuary. Vineyard floor management practices typically consist of a combination of weed control strategies, including herbicide use and cover crops. We evaluated nine combinations of vineyard floor management practices for their impacts on fruit yield, quality and costs. We found that compared to the grower standard, post-emergence herbicide treatments generally used smaller amounts of chemicals and were less costly, with similar yields and quality.
Expanded Abstract | HTML w/Links | PDF

Minimum tillage could benefit California rice farmers
by Bruce Linquist, Albert Fischer, Larry Godfrey, Chris Greer, James Hill, Kaden Koffler, Michael Moeching, Randal Mutters, Chris van Kessel
pp24-29, doi#10.3733/ca.v062n01p24
Abstract
Field research and grower interviews were used to evaluate the potential of minimum tillage for California rice systems. We found that by tilling only in the fall (instead of both the fall and spring), rice farmers can control herbicide-resistant weeds when combined with a stale rice seedbed, which entails spring flooding to germinate weeds followed by a gly-phosate application to kill them. Our results indicated that yield potentials are comparable between water-seeded minimum- and conventional-till systems. We also found that rice growers can reduce fuel costs and plant early. However, minimum tillage may require more nitrogen fertilizer to achieve these yields.
Expanded Abstract | HTML w/Links | PDF

Postharvest survival of navel orangeworm assessed in pistachios
by Joel P. Siegel, L.P.S. (Bas) Kuenen, Bradley S. Higbee, Patricia Noble, Richard Gill, Glen Y. Yokota, Rodrigo Krugner, Kent M. Daane
pp30-35, doi#10.3733/ca.v062n01p30
Abstract
Controlling navel orangeworm, a key pistachio pest, is problematic because the moth overwinters in “mummy” nuts. After harvest, there may be more than 30,000 pistachio nuts (mummies) left behind per acre. To provide better information for winter sanitation decisions, we investigated the number of available mummies and their levels of navel orangeworm infestation from winter through early summer in California pistachio orchards. Navel orangeworm mortality was highest from late December through mid-February, and was also higher on the ground than in trees. Mortality on the ground was highest when mummies were tilled or mowed with the groundcover than when nuts were left on the raised berm. Our data indicates that, in contrast to almonds, it is more productive to focus on clearing pistachios from the ground than on removing them from trees. However, winter sanitation procedures also should be augmented in order to destroy more overwintering navel orangeworm.
Expanded Abstract | HTML w/Links | PDF

Bait formulations and longevity of navel orangeworm egg traps tested
by L.P.S. (Bas) Kuenen, Walt Bentley, Heather C. Rowe, Brian Ribeiro
pp36-39, doi#10.3733/ca.v062n01p36
Abstract
Standardization of pest monitoring practices and materials to maximize sensitivity to pest populations in the field is a foundation of effective integrated pest management (IPM). In response to changes in the availability of commercial bait material for navel orangeworm (NOW) egg traps, we evaluated potential alternative bait materials for use in monitoring this key pest of almonds, pistachios, walnuts and figs. Navel orangeworm egg traps baited with uninfested nutmeats were as effective as almond meal plus 10% crude almond oil, whereas traps baited with freeze-killed, navel orangeworm-infested nutmeats were less effective. The use of nut mummies (culled during winter orchard sanitation) as trap bait may not produce consistent results since the level of navel orangeworm infestation of these nuts is typically unknown. Three seasons of field tests showed that egg traps baited with almond meal plus 3% or 10% crude almond oil received similar numbers of navel orangeworm eggs, and these traps were equally effective for at least 10 weeks.
Expanded Abstract | HTML w/Links | PDF

Public work projects cultivate youth in workforce development programs
by David Campbell, Jean Lamming, Cathy Lemp, Ann Brosnahan, Carole Paterson, John Pusey
pp40-46, doi#10.3733/ca.v062n01p40
Abstract
Using comparative case studies, we evaluated youth workforce development programs in California that are funded by the Workforce Investment Act (WIA) and implemented by local Youth Councils and Workforce Investment Boards. First, we identified a promising practice: skill- and pride-generating public work projects. Next, we identified three characteristics of these successful youth public work initiatives: (1) combining employment preparation with social services and personal support; (2) grouping youth in cohorts that work and learn together; and (3) providing caring adult supervision that combines discipline and support. Proactive investments in high-quality programs with these characteristics can reduce the growing number of out-of-school, out-of-work youth in California, save future public costs for the criminal justice and social service systems, and provide youth with meaningful employment opportunities.
Expanded Abstract | HTML w/Links | PDF

Editorial, News, Letters and Science briefs

EDITORIAL: UC know-how can boost California wine economy
by Andrew L. Waterhouse, Neal Van Alfen
pp2, doi#10.3733/ca.v062n01p2
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Letters
From our readers
pp5-6, doi#10.3733/ca.v062n01p5
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EDITORIAL: Laue leads Cal Ag into digital future
Editors
pp6, doi#10.3733/ca.v062n01p6a
HTML w/Links | PDF

Service grants allow 4H-ers to build healthier communities
by Hazel White
pp6-7, doi#10.3733/ca.v062n01p6b
HTML w/Links | PDF

Oiled birds cleaned up and sent home; research studies launched
by Robin Meadows
pp7-8, doi#10.3733/ca.v062n01p7
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UC Cooperative Extension helps people cope with Southern California wildfires
by Robin Meadows
pp8-9, doi#10.3733/ca.v062n01p8
HTML w/Links | PDF

Trained ovines chomp on weeds, avoid vines
by Robin Meadows
pp10, doi#10.3733/ca.v062n01p10
HTML w/Links | PDF

Mapping shows continued vineyard expansion in premium wine-growing areas
Editors
pp11, doi#10.3733/ca.v062n01p11
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Ecology and Management of Mindarus kinseyi Voegtlin (Aphidoidea: Mindaridae) on White-Fir Seedlings at a California Forest Nursery

by L. E. Ehler, M. G. Kinsey
pp1-62, doi#10.3733/hilg.v62n01p006
Abstract
In recent years, an aphid identified as balsam twig aphid, Mindarus abietinus Koch, was observed on seedlings of white fir (Abies concolor [Gord. & Glend.] Lindl.) at the USDA—Forest Service Nursery near Placerville, California. Both first- and second-year seedlings were infested and aphid-induced stunting of seedlings was observed. Investigations during 1989–92 revealed that the aphid had a life cycle that differed from that reported for M. abietinus. The following stages were detected: egg, fundatrix, vivipara (apterous and alate), sexupara (apterous and alate), and sexualis (male and ovipara). Third and subsequent generations of apterous viviparae were observed; these, plus the alate viviparae and the apterous sexuparae, have not been recorded for other Mindarus species. Aphid populations first appeared in spring, but persisted throughout the summer, fall, and well into winter. The aphid was recently described as Mindarus kinseyi Voegtlin. Ecological studies of M. kinseyi revealed that initial infestation of first-year seedlings was coincident with the discrete flight period of alate viviparae. Alates presumably originated in nearby plantings of second-year seedlings, or in white fir growing at other nearby sites. Alate colonization generally led to an aphid population that was distributed in patches in first-year seedlings. Mean aphid density peaked at replacecodegt25 per seedling (replacecodegt100 per infested seedling), and up to 21% of the first-year seedlings were infested. Initial infestation of second-year seedlings was due to either overwintering eggs (deposited on first-year seedlings), alate viviparae, or both. Early infestations were also patchily distributed, and in some cases, over 50% of the seedlings were eventually infested. Aphid eggs were also present on about 20% of the harvested seedlings destined for outplanting. Naturally occurring predators and parasites were not able to maintain aphid populations at low levels. The aphid's major enemies at the nursery were aphidophagous predators, primarily larvae of syrphid flies. Survival of marked seedlings from emergence to harvest was very high (97.3%). However, cull-rate at harvest was independent of previous aphid infestation. Mean height, stem diameter, and dry weight of marked seedlings at harvest were not significantly reduced by aphid infestation. However, for marked seedlings infested early during the first season, both final height and dry weight were significantly reduced. Thus, aphid infestations can have a significant impact on growth of seedlings, but this does not necessarily lead to an increase in cull-rate at harvest. However, aphid caused mortality of first-year seedlings must also be considered. Additional seedlings were monitored at outplantings in the Eldorado and Stanislaus National Forests during 1991 and 1992. Seedlings were infested with aphids during the first year; however, seedling mortality was independent of aphid infestation during the season. A management program for M. kinseyi was developed and evaluated at the nursery. The program was based on careful monitoring, particularly during the aphid flight season, and spot treatment with compatible suppressive measures. The use of reflective lath fencing (placed horizontally over first-year seedlings) was not effective in reducing alate colonization. Larvae of the lacewings Chrysoperla carnea (Stephens) and C. rufilabris (Burmeister) were released in infested patches and provided good aphid suppression in most cases. Safer® insecticidal soap was also successfully employed as a spot treatment. In a management demonstration, about 10% of the first-year seedlings in the control group (without treatment) were infested by the end of the season compared to only about 1% in the management plot; all infestations in the latter were treated with either larvae of C. rufilabris, Safer® soap, or both. During the second season, all infested patches in the management plot were treated with Safer® soap; by the end of the season, about 20% of the seedlings in the control showed aphid damage compared to approximately 3% in the management plot. At harvest, the cull rate for both plots was relatively high, but independent of aphid infestation. The management program was evaluated again in 1992 with similar results. The pest status of M. kinseyi should be evaluated on a case-by-case basis and the management program implemented as needed. The primary aphid-suppression tactics (soap sprays, lacewing larvae) that were effective in a nursery setting could also be employed against M. kinseyi at Christmas-tree farms.
PDF

Ecology and Management of Mindarus kinseyi Voegtlin (Aphidoidea: Mindaridae) on White-Fir Seedlings at a California Forest Nursery

by L. E. Ehler, M. G. Kinsey
pp1-62, doi#10.3733/hilg.v62n01p006
Abstract
In recent years, an aphid identified as balsam twig aphid, Mindarus abietinus Koch, was observed on seedlings of white fir (Abies concolor [Gord. & Glend.] Lindl.) at the USDA—Forest Service Nursery near Placerville, California. Both first- and second-year seedlings were infested and aphid-induced stunting of seedlings was observed. Investigations during 1989–92 revealed that the aphid had a life cycle that differed from that reported for M. abietinus. The following stages were detected: egg, fundatrix, vivipara (apterous and alate), sexupara (apterous and alate), and sexualis (male and ovipara). Third and subsequent generations of apterous viviparae were observed; these, plus the alate viviparae and the apterous sexuparae, have not been recorded for other Mindarus species. Aphid populations first appeared in spring, but persisted throughout the summer, fall, and well into winter. The aphid was recently described as Mindarus kinseyi Voegtlin. Ecological studies of M. kinseyi revealed that initial infestation of first-year seedlings was coincident with the discrete flight period of alate viviparae. Alates presumably originated in nearby plantings of second-year seedlings, or in white fir growing at other nearby sites. Alate colonization generally led to an aphid population that was distributed in patches in first-year seedlings. Mean aphid density peaked at replacecodegt25 per seedling (replacecodegt100 per infested seedling), and up to 21% of the first-year seedlings were infested. Initial infestation of second-year seedlings was due to either overwintering eggs (deposited on first-year seedlings), alate viviparae, or both. Early infestations were also patchily distributed, and in some cases, over 50% of the seedlings were eventually infested. Aphid eggs were also present on about 20% of the harvested seedlings destined for outplanting. Naturally occurring predators and parasites were not able to maintain aphid populations at low levels. The aphid's major enemies at the nursery were aphidophagous predators, primarily larvae of syrphid flies. Survival of marked seedlings from emergence to harvest was very high (97.3%). However, cull-rate at harvest was independent of previous aphid infestation. Mean height, stem diameter, and dry weight of marked seedlings at harvest were not significantly reduced by aphid infestation. However, for marked seedlings infested early during the first season, both final height and dry weight were significantly reduced. Thus, aphid infestations can have a significant impact on growth of seedlings, but this does not necessarily lead to an increase in cull-rate at harvest. However, aphid caused mortality of first-year seedlings must also be considered. Additional seedlings were monitored at outplantings in the Eldorado and Stanislaus National Forests during 1991 and 1992. Seedlings were infested with aphids during the first year; however, seedling mortality was independent of aphid infestation during the season. A management program for M. kinseyi was developed and evaluated at the nursery. The program was based on careful monitoring, particularly during the aphid flight season, and spot treatment with compatible suppressive measures. The use of reflective lath fencing (placed horizontally over first-year seedlings) was not effective in reducing alate colonization. Larvae of the lacewings Chrysoperla carnea (Stephens) and C. rufilabris (Burmeister) were released in infested patches and provided good aphid suppression in most cases. Safer® insecticidal soap was also successfully employed as a spot treatment. In a management demonstration, about 10% of the first-year seedlings in the control group (without treatment) were infested by the end of the season compared to only about 1% in the management plot; all infestations in the latter were treated with either larvae of C. rufilabris, Safer® soap, or both. During the second season, all infested patches in the management plot were treated with Safer® soap; by the end of the season, about 20% of the seedlings in the control showed aphid damage compared to approximately 3% in the management plot. At harvest, the cull rate for both plots was relatively high, but independent of aphid infestation. The management program was evaluated again in 1992 with similar results. The pest status of M. kinseyi should be evaluated on a case-by-case basis and the management program implemented as needed. The primary aphid-suppression tactics (soap sprays, lacewing larvae) that were effective in a nursery setting could also be employed against M. kinseyi at Christmas-tree farms.
PDF

Ecology and Management of Mindarus kinseyi Voegtlin (Aphidoidea: Mindaridae) on White-Fir Seedlings at a California Forest Nursery

by L. E. Ehler, M. G. Kinsey
pp1-62, doi#10.3733/hilg.v62n01p006
Abstract
In recent years, an aphid identified as balsam twig aphid, Mindarus abietinus Koch, was observed on seedlings of white fir (Abies concolor [Gord. & Glend.] Lindl.) at the USDA—Forest Service Nursery near Placerville, California. Both first- and second-year seedlings were infested and aphid-induced stunting of seedlings was observed. Investigations during 1989–92 revealed that the aphid had a life cycle that differed from that reported for M. abietinus. The following stages were detected: egg, fundatrix, vivipara (apterous and alate), sexupara (apterous and alate), and sexualis (male and ovipara). Third and subsequent generations of apterous viviparae were observed; these, plus the alate viviparae and the apterous sexuparae, have not been recorded for other Mindarus species. Aphid populations first appeared in spring, but persisted throughout the summer, fall, and well into winter. The aphid was recently described as Mindarus kinseyi Voegtlin. Ecological studies of M. kinseyi revealed that initial infestation of first-year seedlings was coincident with the discrete flight period of alate viviparae. Alates presumably originated in nearby plantings of second-year seedlings, or in white fir growing at other nearby sites. Alate colonization generally led to an aphid population that was distributed in patches in first-year seedlings. Mean aphid density peaked at replacecodegt25 per seedling (replacecodegt100 per infested seedling), and up to 21% of the first-year seedlings were infested. Initial infestation of second-year seedlings was due to either overwintering eggs (deposited on first-year seedlings), alate viviparae, or both. Early infestations were also patchily distributed, and in some cases, over 50% of the seedlings were eventually infested. Aphid eggs were also present on about 20% of the harvested seedlings destined for outplanting. Naturally occurring predators and parasites were not able to maintain aphid populations at low levels. The aphid's major enemies at the nursery were aphidophagous predators, primarily larvae of syrphid flies. Survival of marked seedlings from emergence to harvest was very high (97.3%). However, cull-rate at harvest was independent of previous aphid infestation. Mean height, stem diameter, and dry weight of marked seedlings at harvest were not significantly reduced by aphid infestation. However, for marked seedlings infested early during the first season, both final height and dry weight were significantly reduced. Thus, aphid infestations can have a significant impact on growth of seedlings, but this does not necessarily lead to an increase in cull-rate at harvest. However, aphid caused mortality of first-year seedlings must also be considered. Additional seedlings were monitored at outplantings in the Eldorado and Stanislaus National Forests during 1991 and 1992. Seedlings were infested with aphids during the first year; however, seedling mortality was independent of aphid infestation during the season. A management program for M. kinseyi was developed and evaluated at the nursery. The program was based on careful monitoring, particularly during the aphid flight season, and spot treatment with compatible suppressive measures. The use of reflective lath fencing (placed horizontally over first-year seedlings) was not effective in reducing alate colonization. Larvae of the lacewings Chrysoperla carnea (Stephens) and C. rufilabris (Burmeister) were released in infested patches and provided good aphid suppression in most cases. Safer® insecticidal soap was also successfully employed as a spot treatment. In a management demonstration, about 10% of the first-year seedlings in the control group (without treatment) were infested by the end of the season compared to only about 1% in the management plot; all infestations in the latter were treated with either larvae of C. rufilabris, Safer® soap, or both. During the second season, all infested patches in the management plot were treated with Safer® soap; by the end of the season, about 20% of the seedlings in the control showed aphid damage compared to approximately 3% in the management plot. At harvest, the cull rate for both plots was relatively high, but independent of aphid infestation. The management program was evaluated again in 1992 with similar results. The pest status of M. kinseyi should be evaluated on a case-by-case basis and the management program implemented as needed. The primary aphid-suppression tactics (soap sprays, lacewing larvae) that were effective in a nursery setting could also be employed against M. kinseyi at Christmas-tree farms.
PDF

Ecology and Management of Mindarus kinseyi Voegtlin (Aphidoidea: Mindaridae) on White-Fir Seedlings at a California Forest Nursery

by L. E. Ehler, M. G. Kinsey
pp1-62, doi#10.3733/hilg.v62n01p006
Abstract
In recent years, an aphid identified as balsam twig aphid, Mindarus abietinus Koch, was observed on seedlings of white fir (Abies concolor [Gord. & Glend.] Lindl.) at the USDA—Forest Service Nursery near Placerville, California. Both first- and second-year seedlings were infested and aphid-induced stunting of seedlings was observed. Investigations during 1989–92 revealed that the aphid had a life cycle that differed from that reported for M. abietinus. The following stages were detected: egg, fundatrix, vivipara (apterous and alate), sexupara (apterous and alate), and sexualis (male and ovipara). Third and subsequent generations of apterous viviparae were observed; these, plus the alate viviparae and the apterous sexuparae, have not been recorded for other Mindarus species. Aphid populations first appeared in spring, but persisted throughout the summer, fall, and well into winter. The aphid was recently described as Mindarus kinseyi Voegtlin. Ecological studies of M. kinseyi revealed that initial infestation of first-year seedlings was coincident with the discrete flight period of alate viviparae. Alates presumably originated in nearby plantings of second-year seedlings, or in white fir growing at other nearby sites. Alate colonization generally led to an aphid population that was distributed in patches in first-year seedlings. Mean aphid density peaked at replacecodegt25 per seedling (replacecodegt100 per infested seedling), and up to 21% of the first-year seedlings were infested. Initial infestation of second-year seedlings was due to either overwintering eggs (deposited on first-year seedlings), alate viviparae, or both. Early infestations were also patchily distributed, and in some cases, over 50% of the seedlings were eventually infested. Aphid eggs were also present on about 20% of the harvested seedlings destined for outplanting. Naturally occurring predators and parasites were not able to maintain aphid populations at low levels. The aphid's major enemies at the nursery were aphidophagous predators, primarily larvae of syrphid flies. Survival of marked seedlings from emergence to harvest was very high (97.3%). However, cull-rate at harvest was independent of previous aphid infestation. Mean height, stem diameter, and dry weight of marked seedlings at harvest were not significantly reduced by aphid infestation. However, for marked seedlings infested early during the first season, both final height and dry weight were significantly reduced. Thus, aphid infestations can have a significant impact on growth of seedlings, but this does not necessarily lead to an increase in cull-rate at harvest. However, aphid caused mortality of first-year seedlings must also be considered. Additional seedlings were monitored at outplantings in the Eldorado and Stanislaus National Forests during 1991 and 1992. Seedlings were infested with aphids during the first year; however, seedling mortality was independent of aphid infestation during the season. A management program for M. kinseyi was developed and evaluated at the nursery. The program was based on careful monitoring, particularly during the aphid flight season, and spot treatment with compatible suppressive measures. The use of reflective lath fencing (placed horizontally over first-year seedlings) was not effective in reducing alate colonization. Larvae of the lacewings Chrysoperla carnea (Stephens) and C. rufilabris (Burmeister) were released in infested patches and provided good aphid suppression in most cases. Safer® insecticidal soap was also successfully employed as a spot treatment. In a management demonstration, about 10% of the first-year seedlings in the control group (without treatment) were infested by the end of the season compared to only about 1% in the management plot; all infestations in the latter were treated with either larvae of C. rufilabris, Safer® soap, or both. During the second season, all infested patches in the management plot were treated with Safer® soap; by the end of the season, about 20% of the seedlings in the control showed aphid damage compared to approximately 3% in the management plot. At harvest, the cull rate for both plots was relatively high, but independent of aphid infestation. The management program was evaluated again in 1992 with similar results. The pest status of M. kinseyi should be evaluated on a case-by-case basis and the management program implemented as needed. The primary aphid-suppression tactics (soap sprays, lacewing larvae) that were effective in a nursery setting could also be employed against M. kinseyi at Christmas-tree farms.
PDF