Central Coast Region Of California Research Articles

Adolescent immigrant youth: Creating spaces of belonging

Abstract Drawing on 24 months of participant observation and interviews with adolescent arrivals in the central coast region of California, this study examines how recently arrived immigrant teens create spaces of belonging. This immigrant population is simultaneously undergoing two life-changing transitions—adolescence and immigration. These two, life-altering transitions, greatly shape the trajectories of immigrant youth in the host country. Unfamiliar with US customs, the educational system, or the mainstream language, adolescent arrivals constantly struggle to belong in a place they hardly know. I advance the concept of immigrant youth vitality to conceptually analyze how shared experiences based on the age of migration and context of reception shape how immigrant youth create safe spaces for themselves. As recent immigrants and teenage newcomers, adolescent arrivals are experiencing for the first time the wrath of anti-immigrant politics directed at them. This study shows that adolescent arrivals often navigate life in the host country by relying on the familiar and their collective experiences including discrimination and exclusion to create spaces where they feel safe and welcomed. I find that by claiming safe spaces the youth actively engage in redefining what belonging means, looks, and feels like for newcomer teenagers.

Organic farmers face persistent barriers to adopting diversification practices in California’s Central Coast

ABSTRACT In the face of myriad environmental challenges associated with industrial agriculture, some farmers and researchers have looked to diversified farming systems as a promising alternative. Despite well-documented ecological benefits, diversification practices remain rare in many regions of the U.S, even amongst organic farmers. Our study focuses on organic farmers in the Central Coast region of California, an area that has played a crucial role in the rise of organic agriculture over the last several decades. Through 20 interviews with farmers who all grow lettuce and 8 interviews with technical assistance providers, we investigate the persistent barriers that growers in this region face in adopting diversification practices including cover cropping, compost application, crop rotation, insectary strips, and hedgerows. We find that high land rents, the predominance of short-term leases, stringent food safety standards, and other supply chain pressures significantly hamper the adoption of diversification practices. In order to surmount these barriers and increase adoption, solutions must be pursued at three interconnected levels: innovation at the farm level, and policy change at the technical and structural levels. Locally-informed, integrated, and innovative policies across these three levels must be explored to support the creation of a more resilient, sustainable, and equitable food system.

Impact of Lygus hesperus (Hemiptera: Miridae) Feeding and Oviposition on Lettuce

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is an important insect pest of lettuce, Lactuca sativa L. in the central coast region of California. However, little is documented on the injury symptoms relative to levels of L. hesperus infestation on lettuce. Experiments were conducted in which lettuce plants were exposed to 0, 1, 3, 5, and 10 L. hesperus adults for 2 and 7 days. The major injury symptom observed was lesions on the midrib of the leaves, and under low to moderate infestation (e.g., one to five adults per plant) after 2 days of exposure these lesions were not significantly different from the insect-free control. Under heavy infestation (e.g., 10 adults per plant), however, lesions developed rather quickly after 2 days of exposure. The number of lesions was positively associated with numbers of feeding sites and eggs. When heavy infestation lasted for a week, most of the plants died. At low to moderate infestation, more lesions developed compared with the insect-free control. After a weeklong exposure, an increase in number of lesions was negatively associated with plant height. The results emphasize the need for regular scouting to facilitate immediate management decisions and actions to reduce losses from L. hesperus feeding and oviposition injury in lettuce.

Exploring farmers markets as a temporary cluster to improve local food economy

PurposeThe purpose of this paper is to explore how to improve the contribution of farmers markets (FMs) to the local food economy and improve their management through a new temporary clustering management approach.Design/methodology/approachThe research encompasses 78 structured interviews with farmers’ market vendors in the central coast region of California. A descriptive statistical and exploratory analysis to capture and evaluate the extent of various clustering activities currently existing in FMs is presented.FindingsAnalysis suggested an existing clustering behavior in FMs with different degrees that would enhance the role of these markets in local food economy. The improved social capital and financial performance of these markets shown in this study outperformed other cluster metrics monitored. Furthermore, there were some positive relationships between knowledge sharing (as a cluster activity) and both integration and financial activities among FMs vendors, highlighting interesting dynamics generated by the temporary nature of these clusters.Research limitations/implicationsThe study was based on an exploratory research design, investigating a selected number of vendors in the central coast region of California. The research does not claim to provide a comprehensive survey of all FMs.Practical implicationsThe analysis resulted in recommendations to improve efficiency of FMs’ practices at both the management level and the strategic level. These recommendations will enhance the contribution of these markets to the local food economy. The results also expand the practical knowledge bodies of regional and local food business development. Finally, the study highlights the social role of FMs through showing social capital as one of the main clustering drivers.Originality/valueThis study contributes to theoretical knowledge concerning the impact of clusters on operation performance by exploring a new temporary proximity that can be added to the existing geographical and digital proximity enriching the clustering approaches debate. Furthermore, the analysis provides specific novel insights into potential operational improvements for current farmers’ market management to enhance their economic and social roles.

Repellent Effects of Essential Oils on AdultBagrada hilarisby Using an Olfactometer

Abstract. Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) is a serious invasive stink bug species in the central coast region of California. Although B. hilaris can be effectively managed using synthetic insecticides, organic growers have limited effective tools to manage this pest. Little is known about repellent effects of essential oils on adult B. hilaris; thus, repellent effect of citronellal, lemongrass oil, geraniol, peppermint oil, thyme oil, rosemary oil, pine needle oil, and vetiver acetate was examined using olfactormeter. In the choice assay, most of the essential oils did not elicit repellency to both female and male adult B. hilaris except geraniol because significantly more B. hilaris chose the empty arm of the olfactometer than the arm with geraniol. Implications of essential oils on B. hilaris management are discussed.

Determination of Fungicide Resistance in Botrytis cinerea from Strawberry in the Central Coast Region of California

Grey mold, caused by Botryis cinerea, is one of the most important diseases of strawberry in California. Management of grey mold typically relies on repeated fungicide applications. The occurrence of fungicide resistance in B. cinerea was examined in the Central Coast strawberry production region of California. In mid-May 2013, 59 samples consisting of a single diseased fruit or plant part with gray mold symptoms were collected from six different strawberry fields. Single hyphal tip cultures were then used for mycelial growth assays to compare sensitivities to four different fungicides—boscalid, fenhexamid, iprodione, and pyraclostrobin. Each isolate was tested against discriminatory doses of each of the fungicides. In addition, representative highly sensitive and highly resistant isolates were tested against a range of fungicide concentrations to determine EC50 values. Although all of the 59 isolates were sensitive to iprodione, 37%, 31%, and 29% of the isolates were resistant to pyraclostrobin, fenhexamid, and boscalid, respectively. In some instances the isolates were dual and triple-resistant to these fungicides. EC50 values were often higher than 100 mg/liter, which was the highest concentration used. Therefore, appropriate fungicide resistance management measures should be employed in strawberry growing areas of the Central Coast region of California. Accepted for publication 19 February 2016. Published 2 March 2016.

Characterization of Lygus hesperus (Hemiptera: Miridae) Feeding and Oviposition Injury on Celery Seedlings

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), can be a serious pest of celery, Apium graveolens dulce (Mill.) Pers. in the Central Coast region of California. Little is known about injury symptoms caused by L. hesperus adults on celery. When celery seedlings were exposed to L. hesperus adults, their crown area was found destroyed with necrotic dead tissue. Destroyed crowns of dead seedlings were observed when seedlings were exposed to five or more L. hesperus adults for ≥24 h but was not observed on seedlings exposed ≤12 h. In addition, elongated lesions were noticed on the celery petiole and were significantly greater when exposed to five or more L. hesperus adults for as little as 4 h. Number of elongated lesion injuries and number of eggs recovered from elongated lesions was correlated (r = 0.66; P < 0.001). Data provide key diagnostic symptoms of L. hesperus feeding and ovipositional injury on celery seedlings. Also, this study expands our understandings on the effects of L. hesperus adult density and duration of exposure which reinforces the need for regular scouting, and immediate management decisions and action to reduce losses from L. hesperus injury in both celery seedlings and mature plants in greenhouse and field settings, respectively Accepted for publication 27 April 2016. Published 4 May 2016.

Crop and Soil Nitrogen Dynamics in Annual Strawberry Production in California

The impact of strawberry production on nitrate contamination of groundwater is of major concern in the central coast region of California. Nitrogen (N) fertilization and irrigation management practices were monitored in a total of 26 fall-planted annual strawberry (Fragaria ×ananassa Duch.) fields in 2010 and 2011. Soil mineral N (SMN, top 30 cm depth) was determined monthly. Irrigation applied was monitored, and crop evapotranspiration (ETc) was estimated. Growers were surveyed regarding their N fertilization practices. Aboveground biomass N accumulation was estimated by monthly plant sampling in seven fields. The effect of preplant controlled-release fertilizer (CRF) rate on fruit yield was investigated in three fields. The growers’ CRF application rate (121 or 86 kg·ha−1 N as 18N–3.5P–10.8K, 7- to 9-month release rating) was compared with a half rate (all fields) and no CRF in one field. The rate of N release from this CRF product was evaluated using a buried bag technique. Median CRF N and total seasonal N application (CRF + in-season fertigation through drip irrigation) were 101 and 260 kg·ha−1, respectively, with total seasonal N application varying among fields from 141 to 485 kg·ha−1. Biomass N accumulation was slow through March (less than 25 kg·ha−1) and then increased by ≈1.1 kg·ha−1·d−1 from April through mid-September. Mean seasonal biomass N accumulation was estimated at 225 kg·ha−1 by 15 Sept. Approximately 70% of CRF N was released before 1 Apr. Biomass N accumulation between planting and April was much lower than the combined amount of CRF N release and SMN decline over that period, suggesting substantial winter N loss. Conversely, N loss during the summer harvest season (May through August) appeared limited in most fields. Median SMN was maintained below 10 mg·kg−1, and median irrigation was 113% of estimated ETc during this period. Reduction in CRF rate did not affect marketable fruit yield in two of three trials; an 8% yield reduction was observed in the remaining trial when the CRF rate was reduced, but the decline may have been affected by spring irrigation and fertigation practices.

Effectiveness of a Text Message Pilot Program Targeting Low-Income Latinos' Dietary Behaviors

ObjectiveTo assess the effectiveness of an innovative texting program on fruit and vegetable (FV) and sugar-sweetened beverage (SSB) consumption among low-income Latinos in California.Target audienceLow-income Latinos (n=579) in the Central Coast region of California.Theory, Prior Research, RationaleRecent studies have shown text messages are a viable means to reach Latinos with healthcare-related information. Seventy percent of English-speaking Latinos report frequent text messaging, versus just over 50% of non-Hispanic Whites.DescriptionFor up to 16 weeks, participants received 2 weekly text messages addressing FV and SSB consumption. Messages included nutrition facts, links to useful websites, and recipes. Participants chose to receive messages in Spanish (n=451) or English (n=128). Messages were tailored based on the existence of children in the home. Participants were recruited passively through posters and flyers and actively by lay health educators and could opt out at any time.EvaluationPre-post test questions were included in the text messages at the beginning and end of the program, respectively. There was a 17% increase in frequency of filling half their plates with FV (p=0.006). Seventy percent of participants reported meeting or exceeding their SSB goals. Unprompted, some participants replied to text messages indicating they had lost weight and their children had stopped drinking SSBs as a result of the program.Conclusions and ImplicationsStudy findings support the effectiveness of texting programs at improving dietary behaviors. The Network for a Healthy California would like to continue to support and expand this program. With the groundwork laid and effective messages already developed, this pilot project could be rolled out statewide.FundingSupplemental Nutrition Assistance Program - Education. ObjectiveTo assess the effectiveness of an innovative texting program on fruit and vegetable (FV) and sugar-sweetened beverage (SSB) consumption among low-income Latinos in California. To assess the effectiveness of an innovative texting program on fruit and vegetable (FV) and sugar-sweetened beverage (SSB) consumption among low-income Latinos in California. Target audienceLow-income Latinos (n=579) in the Central Coast region of California. Low-income Latinos (n=579) in the Central Coast region of California. Theory, Prior Research, RationaleRecent studies have shown text messages are a viable means to reach Latinos with healthcare-related information. Seventy percent of English-speaking Latinos report frequent text messaging, versus just over 50% of non-Hispanic Whites. Recent studies have shown text messages are a viable means to reach Latinos with healthcare-related information. Seventy percent of English-speaking Latinos report frequent text messaging, versus just over 50% of non-Hispanic Whites. DescriptionFor up to 16 weeks, participants received 2 weekly text messages addressing FV and SSB consumption. Messages included nutrition facts, links to useful websites, and recipes. Participants chose to receive messages in Spanish (n=451) or English (n=128). Messages were tailored based on the existence of children in the home. Participants were recruited passively through posters and flyers and actively by lay health educators and could opt out at any time. For up to 16 weeks, participants received 2 weekly text messages addressing FV and SSB consumption. Messages included nutrition facts, links to useful websites, and recipes. Participants chose to receive messages in Spanish (n=451) or English (n=128). Messages were tailored based on the existence of children in the home. Participants were recruited passively through posters and flyers and actively by lay health educators and could opt out at any time. EvaluationPre-post test questions were included in the text messages at the beginning and end of the program, respectively. There was a 17% increase in frequency of filling half their plates with FV (p=0.006). Seventy percent of participants reported meeting or exceeding their SSB goals. Unprompted, some participants replied to text messages indicating they had lost weight and their children had stopped drinking SSBs as a result of the program. Pre-post test questions were included in the text messages at the beginning and end of the program, respectively. There was a 17% increase in frequency of filling half their plates with FV (p=0.006). Seventy percent of participants reported meeting or exceeding their SSB goals. Unprompted, some participants replied to text messages indicating they had lost weight and their children had stopped drinking SSBs as a result of the program. Conclusions and ImplicationsStudy findings support the effectiveness of texting programs at improving dietary behaviors. The Network for a Healthy California would like to continue to support and expand this program. With the groundwork laid and effective messages already developed, this pilot project could be rolled out statewide. Study findings support the effectiveness of texting programs at improving dietary behaviors. The Network for a Healthy California would like to continue to support and expand this program. With the groundwork laid and effective messages already developed, this pilot project could be rolled out statewide.

Coastal Ecosystems and Agricultural Land Use: New Challenges on California's Central Coast

This article uses the Central Coast region of California as a case study to examine the challenges of protecting coastal ecosystems near areas of intensive agricultural production. Coastal water quality and biodiversity are greatly impacted by regional land use. Agricultural land use can have significant impacts on water quality through erosion and the runoff of agricultural chemicals. While the Central Coast region of California is a center for intensive agricultural production, it is also home to the largest marine sanctuary in the United States. This combination has resulted in intensive efforts from government agencies and conservation organizations to reduce pollution associated with agriculture. Efforts have focused on education and incentives, but are recently facing increasing challenges stemming from new standards created by the produce industry in response to food safety concerns. Personal interviews with crop growers were used to explore these challenges and to better understand the range of possible environmental impacts resulting from new food safety standards. Results indicate that substantial management changes are taking place that are likely to impact regional water quality and wildlife. This case study also explores the role of policy networks in shaping management decisions and illustrates how certain approaches to addressing agricultural pollution may be vulnerable to external policy changes.

Black Bear Population Genetics in California: Signatures of Population Structure, Competitive Release, and Historical Translocation

The contemporary genetic structure of animal populations is sculpted by past events, including demographic bottlenecks and expansions and movement of animals by humans. In an analysis of microsatellite DNA of black bears (Ursus americanus; n 5 540) across California, we discovered distinct population structure and genetic evidence of 2 historic colonization events. First, genotypes of bears sampled in southern California are most related to those from the Yosemite National Park region and not with spatially intervening populations. Historical records recount the translocation of 28 black bears from the Yosemite National Park area of the central Sierra Nevada to the San Bernardino Mountains in southern California in the 1930s. Second, before colonization of California by Europeans, the Central Coast region was inhabited by the now extinct California grizzly bear (Ursus arctos californiensis), but not black bears. Following an apparent competitive release and range expansion during the past century, black bears now inhabit the Central Coast region of California. Black bears in California’s Central Coast display lower genetic diversity (founder effect) and a genetic signature most closely allied with black bears from the southern Sierra Nevada. In both these cases, molecular genetic techniques allowed historical reconstruction of anthropogenic events leading to changes in animal distributions.

New Zealand exports: Pseudosphaeroma Chilton, 1909 (Isopoda: Sphaeromatidae), a Southern Hemisphere genus introduced to the Pacific coast of North America

Collections made along the coast of California have revealed the presence of a species of Pseudosphaeroma Chilton, 1909, a genus common in New Zealand coastal waters. The genus is entirely Southern Hemisphere in distribution, and this record reports the introduction of a species of Pseudosphaeroma into the San Francisco and Central Coast region of California, the first reported occurrence of the genus as an invasive taxon, and the first record of the genus from the Northern Hemisphere. The genus is also recorded for the first time from the Galapagos and Argentina.

The Density of Retail Food Outlets in the Central Coast Region of California: Associations with Income and Latino Ethnic Composition

ABSTRACT Research in the United States has found more limited retail food access in low-income and minority areas. This study analyzed retail food density in census blocks of Santa Cruz, Monterey, and San Benito Counties in California (n = 6308), using GIS and multilevel regression models. The results indicate that the density of retail food outlets was lower in census blocks with a majority of Latino residents. However, retail density increased with declining median household income in census block groups (n = 396). Suitable locations for establishing new fruit and vegetable markets in the region were also identified, as a potential means of reducing current inequalities.

Development and Commercialization of a Complete Vineyard Mechanization System

A major research thrust of the University of Arkansas Enology and Viticulture Program for the past 37 years has been the development of a total vineyard mechanization system. This new system allows the mechanization of almost all practices in vineyard operations, including dormant and summer pruning, leaf removal, shoot and fruit thinning, canopy management, and harvesting while fruit quality is maintained or enhanced. Research efforts aimed to accomplish these tasks on the 12 major trellising systems used throughout the industry and to derive plans for the sequencing and timing of operations on each of the trellis systems. In 2002, the University of Arkansas patented the Morris-Oldridge Vineyard Mechanization System (M-O System). OXBO International Corp., Clear Lake, WI, purchased the patent and market M-O System components under the name Korvan™ Vineyard System. The objective of this study was to evaluate the effectiveness of mechanized (machine-farmed) pruning, shoot thinning, and fruit thinning using the M-O System vs. traditional methods of canopy management using hand labor (hand-farmed) in a commercial Vitis vinifera vineyard in the central coast region of California. V. vinifera cultivars evaluated included Chardonnay, Sauvignon blanc, and Syrah trellised on a lyre system and Merlot, Zinfandel, and Sangiovese trellised on a vertical shoot-positioned (VSP) system. Yield, fruit growth, fruit composition, wine quality, wine sensory attributes, and economics of mechanization were evaluated on machine- and hand-farmed grapes. Mechanized studies were initiated at French Camp Vineyards, Santa Margarita, CA, in 2002. French Camp Vineyards used a balanced cropping concept which incorporated three operations: 1) machine dormant pruning, 2) machine shoot thinning, and 3) machine fruit thinning. Results of research from 2002 to 2005 showed that yield and quality characteristics of machine-farmed grapes were not statistically different from those of hand-farmed grapes for the V. vinifera cultivars in this study. Wines from each cultivar and treatment were produced at a commercial winery and after appropriate aging, were sensory-evaluated by a professional wine analysis service. Few sensory differences were found between wines from the two farming systems. Further objective analyses of the wine components showed no commercially practical differences. In 2006, cost estimates were derived for the three vineyard activities necessary to achieve balanced cropping. Use of machine farming for balanced cropping operations resulted in savings over hand farming of 45% on the lyre trellis, 49% on the VSP system, and 62% on the quadrilateral trellis for the operations studied. Studies of mechanization of vineyard activities using the M-O System to achieve balanced cropping have shown that grapes and their wines were equivalent to those obtained using hand labor for these operations with the added benefit of cost savings for the operations evaluated.

Beyond organic: consumer interest in new labelling schemes in the Central Coast of California

AbstractProducers are interested in developing labelling schemes that go ‘beyond organic’ to address ethical criteria not included the US Department of Agriculture organic standards. However, consumer interests in labels that are not as widely available as organic in the market are poorly understood. This study reports results of focus‐group research and a survey of 1000 households in the Central Coast region of California to determine which standards consumers are most interested in supporting through their purchases. The results indicate that standards for the humane treatment of animals have the highest level of support, followed by a standard for local origin, and for a living wage for workers involved in producing food. Logistic regression analysis suggests that humane is more likely to be chosen by women, European‐Americans, younger people and frequent organic purchasers. Locally grown was preferred by older people and households with children. A living wage for workers involved in food production was selected more often by Latinos. Although a characterization of trends is not possible due to a cross‐sectional design, the results suggest some potential directions for producers in this region who are willing to supply unmet consumer demands for ethical criteria. There are three basic directions that new and emerging labels may take with respect to US national organic standards: (1) separate from organic; (2) institutionally separate, but tightly integrated with organic; and (3) intended to supplant organic. The success of each of these strategies will depend on how much trust consumers continue to place in government oversight of organic food. The study results also suggest that the movement for a more sustainable food system would benefit from devoting more attention to issues of animal rights and social justice.

Jasmonic Acid: A Vaccine Against Leafminers (Diptera: Agromyzidae) in Celery

Plant resistance to herbivores can be induced by application of elicitors such as jasmonic acid, which is a signal molecule that increases naturally in plants that have been damaged. The use of elicitors to induce resistance of crop plants against herbivores has been successful in small scale experiments but has not been developed in commercial agriculture. We tested jasmonic acid sprays as elicitors of resistance against leafminers and other pests on commercial celery fields in the central coast region of California. In two of three trials, significantly fewer leafminer adults emerged from the plants sprayed with jasmonic acid than the plants that were left untreated. In these two trials, aphid control was erratic, and thrips were not significantly reduced on the treated plants although thrips were not common during the trials. Leafminer parasitoid population densities tracked the number of available leafminer hosts regardless of treatment. The only effect found in the third trial was that conventionally grown celery had more leafminer oviposition stings than either the plants treated with jasmonic acid or untreated control plants. Treatment of plants with jasmonic acid seems to hold promise as an alternative pest management tool.

Jasmonic Acid: A Vaccine Against Leafminers (Diptera: Agromyzidae) in Celery

Plant resistance to herbivores can be induced by application of elicitors such as jasmonic acid, which is a signal molecule that increases naturally in plants that have been damaged. The use of elicitors to induce resistance of crop plants against herbivores has been successful in small scale experiments but has not been developed in commercial agriculture. We tested jasmonic acid sprays as elicitors of resistance against leafminers and other pests on commercial celery fields in the central coast region of California. In two of three trials, significantly fewer leafminer adults emerged from the plants sprayed with jasmonic acid than the plants that were left untreated. In these two trials, aphid control was erratic, and thrips were not significantly reduced on the treated plants although thrips were not common during the trials. Leafminer parasitoid population densities tracked the number of available leafminer hosts regardless of treatment. The only effect found in the third trial was that conventionally grown celery had more leafminer oviposition stings than either the plants treated with jasmonic acid or untreated control plants. Treatment of plants with jasmonic acid seems to hold promise as an alternative pest management tool.

Presidedress Soil Nitrate Testing Reduces Nitrogen Fertilizer Use and Nitrate Leaching Hazard in Lettuce Production

Trials were conducted in 15 commercial fields in the central coast region of California in 1999 and 2000 to evaluate the use of presidedress soil nitrate testing (PSNT) to determine sidedress N requirements for production of iceberg and romaine lettuce (Lactuca sativa L.). In each field a large plot (0.2-1.2 ha) was established in which sidedress N application was based on presidedress soil NO3-N concentration. Prior to each sidedress N application scheduled by the cooperating growers, a composite soil sample (top 30 cm) was collected and analyzed for NO3-N. No fertilizer was applied in the PSNT plot at that sidedressing if NO3-N was >20 mg·kg-1; if NO3-N was lower than that threshold, only enough N was applied to increase soil available N to ≈20 mg·kg-1. The productivity and N status of PSNT plots were compared to adjacent plots receiving the growers' standard N fertilization. Cooperating growers applied a seasonal average of 257 kg·ha-1 N, including one to three sidedressings containing 194 kg·ha-1 N. Sidedressing based on PSNT decreased total seasonal and sidedress N application by an average of 43% and 57%, respectively. The majority of the N savings achieved with PSNT occurred at the first sidedressing. There was no significant difference between PSNT and grower N management across fields in lettuce yield or postharvest quality, and only small differences in crop N uptake. At harvest, PSNT plots had on average 8 mg·kg-1 lower residual NO3-N in the top 90 cm of soil than the grower fertilization rate plots, indicating a substantial reduction in subsequent NO3-N leaching hazard. We conclude that PSNT is a reliable management tool that can substantially reduce unnecessary N fertilization in lettuce production.

First Report of Powdery Mildew Caused by Erysiphe heraclei on Celery in North America.

Since 1994, a fungal disease has been affecting celery (Apium graveolens) grown for seed in the central coast region of California. White, ectophytic mycelia and conidia, characteristic of a powdery mildew, were present on compound umbels, including the involucre, rays, raylets, flowers, and fruits. Celery with powdery mildew had twisted flower petals, and the disease possibly contributed to premature senescence and drying of the fruits. Powdery mildew was not observed on leaves. Mycelial growth was effused and amphigenous and had lobed appressoria. Conidiophores were straight, and cylindrical foot cells were followed by a longer cell and one or two shorter cells. Conidia were produced singly and were 36 to 44 × 11 to 16 μm. Fibrosin bodies were not observed. Germ tubes were located at the ends of conidia and formed lobed appressoria. Cleistothecia were not present. Based on these characteristics, the fungus was identified as Erysiphe heraclei (1). In California, parsley (Petroselinum crispum) is a host of E. heraclei (4), and parsley is grown in the same region as celery seed crops. To determine if parsley was an alternative host of the celery powdery mildew, infected celery umbels were gently pressed onto adaxial surfaces of leaves on 2-month-old greenhouse grown parsley cvs. Italian Plain and Triple Curled. Inoculated plants were incubated 48 h in a moist chamber at 22°C, then transferrred to a greenhouse at 22 ± 2°C / 16 ± 2°C day/night temperatures, 75% relative humidity, and natural light. After 12 to 14 days, powdery mildew was observed on both parsley cultivars. Uninoculated control plants did not develop the disease. This is the first report of powdery mildew on celery in North America. Previous reports list E. heraclei on celery in Chile, the former Czechoslovakia, France, Iraq, Italy, and the former USSR (Georgia region). In the U.S., E. heraclei is reported on carrot (Daucus carota) (2), parsley (4), meadow parsnip (Zizia aptera and Z. aurea) (3), and now celery.

Studies on the Distribution of the Pit Scale Asterolecanium minus on Oak Trees

Samples of branches were taken from various parts of valley oak (Quercus lobata Nee) trees in the central coast region of California during the dormant and growing seasons in 1962 for determination of numbers of Aster olecanium minus Lindinger (Homoptera: Asterolecaniidae). Scale density was found to decrease in a linear manner as height in the tree increased and as age of wood increased from 1 to 7 years. Densities were consistently lower, however, on terminal twigs than on the growth made 1 year earlier. On both upward- and on downward-growing terminal twigs, scales tended to orient the body with the anterior end directed toward the base of the twig. An attempt was made to provide an explanation for each of the relationships described.