Scion/Rootstock Incompatibility as the Cause of Tree Decline in Fukumoto Navel Craig Kallsen and Neil O'Connell
The objective of this research begun in 2003 is to explore scion/rootstock incompatibility as a possible cause of tree decline in Fukumoto navel. Tree decline in Fukumoto navel has been characterized by poor growth -- especially of the scion -- profuse sucker proliferation at the graft union, and sparse yellow leaf canopies.
( 171 kb)

Petroleum Oils as Navel Orange and Tangelo Fruit Thinning Agents Craig Kallsen
Since the 2001-02 crop year, the major objective of this project has been to determine how a summer application of 10 gallons of a 440-weight narrow-range petroleum oil in a 200-gallon per-acre spray solution affects the alternate bearing, fruit size and yield of Minneola tangelo. Although the original title of this project has been retained for continuity, petroleum oil as used in this study has not yet thinned Minneola tangelo fruit.
( 101 kb)

Registration of 2,4-D for Fruit Size and Yield Increase of Mandarins and Mandarin Hybrids in California C. Thomas Chao
The overall goal of this project is to seek permanent registration of 2,4-D for fruit size increase of mandarins and mandarin hybrids in California.
( 112 kb)

Improving the Efficacy of GA3 to Increase Fruit Set and Yield of Clementine Mandarins in California C. Thomas Chao and Carol J. Lovatt
The overall goals of this research are to identify the proper rate, proper timing, and best frequency of GA3 and/or 1% urea applications to increase fruit set and yield of Nules Clementine mandarin. We will also determine if there is any negative effect on the current and following year's yield due to too high a concentration or too frequent applications of moderate rates of GA3.
( 109 kb)

Production and Management Strategies for New Mandarins in California C. Thomas Chao
The main project objectives in 2004-2005 were to study compatibility and seediness among mandarins.
( 102 kb)

Metabolomic Analysis of Citrus Pat Unkefer
Metabolomics is the study of the entire metabolome within a system, allowing for a more comprehensive look at how that system functions and reacts. The overall objective of this project is to establish metabolomics as a useful tool to analyze the metabolic state of citrus (navel orange).
( 95 kb)

Using Regulated Deficit Irrigation to Optimize Fruit Size in Late Harvest Navels David A. Goldhamer
Grower profits with late harvest navels can be significantly reduced due to both excessively large fruit and granulation. We are evaluating regulated deficit irrigation (RDI) as a technique to produce optimal-sized high-quality fruit with late harvest (Lane Late) navels.
( 438 kb)

Irrigation Stress and Early Navel Fruit Maturity Craig Kallsen
The objective of this experiment is to measure the effects of three levels of water stress initiated approximately August 1 on navel orange fruit size, yield, sugar/acid, color, and juice percentage.
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Etiology and Management of Rind Breakdown of Mandarins J. E. Adaskaveg
Recent reports of preharvest rind decay of mandarins included cases with severe crop losses in some citrus areas of California (Butte, Fresno, Tulare, and Kern). The damage generally occurred shortly after rainfalls and was most severe on Satsuma mandarins.
( 106 kb)

New Field Uses for Four Commercial PGRs Carol J. Lovatt
The goal of this research is to determine the commercial value (cost/benefit) of four PGRs -- CPPU, AVG, Prohexadione-Ca, and 3,5,6TPA -- to solve citrus production problems.
( 126 kb)

Seasonal Variations in N Uptake and Nutrient Concentrations in Mature Field-Grown Citrus Robert R. Krueger
The objectives of this study were to measure seasonal variations in mineral nutrient concentration and mass in vegetative organs and fruit of mature citrus trees, to estimate seasonal variations in nitrogen uptake, and to estimate the amount of nitrogen removed from soil.
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Rootstock Breeding and Evaluation Mikeal L. Roose
The general objectives of this project are to develop, test, and evaluate citrus rootstocks for disease and pest tolerance, and to select stocks which impart to the scion high yield, superior fruit quality, acceptable fruit size, and other essential traits.
( 106 kb)

Citrus Variety Evaluation for Trueness-to-Type and Commercial Potential Tracy L. Kahn
High quality citrus varieties which are adapted to California climates and meet market needs are crucial to the industry to maintain competitiveness in the global and domestic fresh citrus markets... In 2004-2005 we evaluated 54 selected mandarin, blood orange, late season navel orange, lemon, and specialty varieties.
( 160 kb)

Breeding of New Citrus Scion Varieties Mikeal L. Roose
The objectives of this project are to develop new mandarin, orange, lemon, and grapefruit cultivars suitable for California conditions. Developing new varieties is a long-term project that has been funded by the CRB since 1994.
( 354 kb)

Harvest and Evaluation of Strain Trials at Lindcove Research and Extension Center Mary Lu Arpaia
Our progress on the two portions of this study is outlined in this report, plus a near-final summary of the Valencia strain portion of the project which was terminated in 2003.
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Evaluation of Lemon Selections for the Desert Glenn C. Wright, Tracy L. Kahn, and Peggy A. Mauk
This project is designed to evaluate particular lemon selections under desert conditions. The major objectives of this project are to provide the industry with information on the tree growth, yield, packout, and fruit quality characteristics for selected lemon varieties in the California desert.
( 131 kb)

Genetic Engineering of Citrus Henry J. Fisk and Abhaya M. Dandekar
The main goal of this work has been to develop genetic transformation methods for citrus scion cultivars important to the California industry. The cultivars investigated during the 2004-2005 funding cycle included Washington navel and Valencia sweet oranges, Kinnow and Owari Satsuma mandarins, Eureka lemon, and Mexican lime.
( 307 kb)

Physiological and Biochemical Determinants of Sugar and Acid Content in Citrus Fruits and Citrus Fruit Proteomics Eduardo Blumwald
Citrus fruit quality standards have been determined empirically, depending on species and on the particular growing season. In general, the TSS to TA ratio determines whether citrus fruit can be marketed. The TSS/TA ratio in citrus fruits is dominated by two main components: overall vacuolar juice cell acidity and juice cell sugar content. The goal of this research is to characterize the physiological and biochemical components that promote and control the accumulation of TSS and TA in citrus
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Development of Citrus Cultivars with Reduced Juvenility Henry J. Fisk
The overall objective of this project has been to develop technology that will allow for the creation of commercially important citrus species that have reduced juvenility. Since most citrus improvement programs involve the use of seedlings, plants with reduced juvenility will prove invaluable for expediting work that is based in conventional breeding, biotechnology, or a combination of the two due to a shorter time period required for screening, evaluations and/or subsequent crosses.
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Improving Peel Quality of California Citrus Fruit Abhaya M. Dandekar
Our study has two specific objectives: (1) To survey the pattern of genes expressed in peel tissues that determine quality of citrus fruit, and (2) To identify and validate genes associated with the development of fruit quality and peel-related external finish disorders.
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Evaluating and Validating Seedlessness Strategies for Citrus Abhaya M. Dandekar
Seedy citrus fruit are a major quality issue and of significant concern to the citrus industry. Elimination of seed formation would be a valuable trait for many citrus cultivars, especially the mandarin varieties and seedy lemon varieties. In this project we will evaluate the role of ovule-specific regulation of auxin to induce parthenocarpy in citrus.
( 102 kb)

EST Libraries and Bioinformatics for California Citrus Timothy J. Close and Mikeal L. Roose
This project provides foundational information in the area of Genomics. The information is about the genes, proteins and metabolic pathways of citrus. This information facilitates other research and practical applications.
( 126 kb)

Genetic Maps of Sweet Orange and Trifoliate Orange Mikeal L. Roose and Timothy J. Close
Genetic linkage maps are used to improve the efficiency of breeding and to identify genes that, if altered using biotechnology, would confer desired traits on the plant. This is a collaborative project involving the Roose and Close labs at UCR and the Fred Gmitter and Jose Chaparro labs at the University of Florida.
( 101 kb)

Microarrays for Gene Expression and Mapping in Citrus Mikeal L. Roose and Timothy J. Close
This project is a supplement to the CRB projects "EST Libraries and Bioinformatics" and "Genetic Maps of Sweet Orange and Trifoliate Orange".
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Controlling Citrus Tristeza Virus by Rootstock Delivery of a CTV RNA Silencing Signal Bryce W. Falk
We completed the fourth and final year of our CRB-funded effort to develop Citrus Tristeza Virus (CTV) RNA silencing as an approach to confer systemic resistance against CTV.
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Breeding a Red-Fleshed Mandarin (Candidate Gene Analysis) Jose X. Chaparro and Andrew Breksa
The primary objective of the project is to gain an understanding of the genetic control of color development in citrus fruit. Peel and flesh color is an important quality trait in citrus. External appearance is the most important factor affecting consumer choice in an impulse purchase of fruit.
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Mandarin Trial for the California Desert Peggy A. Mauk and Tracy L. Kahn
The major objectives of our project were to provide the industry with information on the tree growth, fruit quality characteristics and timing of legal maturity for selected mandarin varieties in the California desert.
( 175 kb)

Biological Characterization of Naturally Occurring Citrus Tristeza Virus Strains in California Citrus and Maintenance of the Isolate Collection MaryLou Polek
This project is not a typical research project; rather, it is one that largely supports the research of several laboratories. Objectives include: (1) Biologically characterize a wide range of CTV isolates occurring naturally in citrus groves throughout California and experimental isolates in support of other research projects; (2) Classify the collected isolates as to severity or potential for causing economic loss either in production or fruit quality; (3) Maintain these characterized isolates
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Biology and Management of Septoria Spot of Citrus J. E. Adaskaveg
Septoria spot of citrus is found in many citrus-producing countries around the world; it is a sporadic disease in California... First reported in the 1940s, recent outbreaks (2003-04 and 2004-05 seasons) have caused trade restrictions for California oranges in the Korean market.
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Etiology, Epidemiology, and Management of Hyphoderma Gummosis J. E. Adaskaveg
Hyphoderma gummosis was first observed in Tulare County in 2000. The disease was subsequently found in numerous lemon orchards in Ventura, Tulare, Riverside and San Luis Obispo Counties.
( 177 kb)

Development and Management of a Genomics Database for Microarray-based Detection Systems for Citrus Pathogens Edwin Civerolo
The specific objective is to develop and manage a database of genomics information related to citrus pathogens and infection and to citrus pathogen-host interactions.
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Development of a Rapid System for Detection of Stubborn Disease in the Field Robert R. Krueger
As reported previously, we have developed a PCR-based test that is reliable and faster than the traditional culture method. Our method utilizes commercial kits for some steps in the process, thus simplifying the procedure.
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San Joaquin Valley Insecticide Efficacy Trials for Citrus Pests Beth Grafton-Cardwell
The purpose of this research program is to determine how insecticides can be used most effectively, with as little disruption of natural enemies as possible, as part of the citrus IPM program. Information derived from this project is used to update the UC IPM Pest Management Guidelines, produce Arthropod Management Test articles, and help support registration of insecticides.
( 143 kb)

Long-term Effects of Chloronicotinyls on Citrus IPM Beth Grafton-Cardwell
Our goal is to assess the impact of Assail on citrus IPM when applied in April-May as a glassy-winged sharpshooter (GWSS) treatment, June as a red scale treatment, or August as a citricola scale treatment. We are also evaluating Admire in April or May as a GWSS treatment.
( 133 kb)

Monitoring for Pesticide Resistance in California Red Scale Beth Grafton-Cardwell
The purpose of our project is to determine if organophosphate insecticide-resistant populations of California red scale have lost any of their resistance to organophosphates (Lorsban or Supracide) and to see if any populations have developed resistance to Esteem.
( 160 kb)

Evaluation of the Effects of Micromite (diflubenzuron) on Forktailed Katydids Beth Grafton-Cardwell
Katydids have become a serious pest of San Joaquin Valley citrus since growers switched from using broad spectrum organophosphate and carbamate insecticides to soft pesticides such as Success for citrus thrips and Esteem for California red scale... Micromite is a recently registered insect growth regulator that appears to have good activity on katydid nymphs and is relatively safe for natural enemies.
( 154 kb)

Infrastructure for Armored Scale Research Robert F. Luck
California red scale remains a primary pest of citrus in the San Joaquin Valley. As new pests enter California citrus, red scale research must develop efficacious control tactics that can integrate into new pest management practices. This ongoing project seeks to foster research by UC Riverside and industry scientists by providing CRS, their associated parasitoids, and assistance in experimental design to achieve this goal.
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Integrating Chloronicotinyl Pesticides with Red Scale Biological Control Joseph G. Morse and Robert F. Luck
This project investigates the impact of a glassy-winged sharpshooter (GWSS) treatment of Admire and a Citricola scale treatment of Assail on the natural enemies suppressing California red scale in the San Joaquin Valley. This project interfaces with Grafton-Cardwell's CRB project, "Long-term Effects of Chloronicotinyls on Citrus IPM."
( 216 kb)

Survey for Soft Scale Parasitoids in Interior Southern California Joseph G. Morse and Robert F. Luck
This project seeks to improve the biological control of black scale in southern California and of citricola scale in the San Joaquin Valley. To do so, we need to better understand which parasitoids attack black scale during the year in southern California and which species in the complex are responsible for the near elimination of citricola scale in this region.
( 174 kb)

Management of Citrus Thrips Joseph Morse
Our citrus thrips research has three current objectives: (1) Continue laboratory and field citrus pesticide efficacy trials in order to evaluate possible new control materials; continue the search for new and effective products with different chemistries; (2) Evaluate citrus thrips resistance to currently used products; and (3) Evaluate biological control agents potentially useful against citrus thrips.
( 111 kb)

Management of Bean Thrips Joseph Morse
Bean thrips are an economic problem for California citrus growers only because adults will overwinter in the navel of navel oranges and may be detected in Australia where they are considered a quarantine pest resulting in the entire load being fumigated with methyl bromide.
( 139 kb)

Development of Novel Repellents for the Honeybee Spiros D. Dimitratos and Daniel F. Woods
This project's goal has been to develop a novel repellent for the honeybee. Our approach to insect control involves nontoxic solutions that manipulate the insect's chemosensory system -- specifically the olfactory and gustatory systems. Since insects use tastes, colors, and other chemical cues from the environment to control important behaviors, products that manipulate the way the insect responds to these cues can alter insect behavior without negatively affecting existing integrated pest man
( 98 kb)

Survey for Woolly Whitefly in Kern County David Haviland
Woolly whitefly has recently been introduced into the southern San Joaquin Valley in residential areas in northeast Bakersfield, Kern County. It appears, however, to have become introduced without the parasitic wasps known to control it in other portions of the state.
( 136 kb)

Development of Pheromone Traps for Monitoring Citrus Leafminer Jocelyn Millar
We report here the identification, synthesis, and testing of a powerful sex pheromone blend for California populations of citrus leafminer, which will greatly increase the speed, simplicity, and effectiveness of detection and monitoring of this pest.
( 140 kb)

Reducing the Negative Impact of Bacterial Infections in Aphytis melinus Richard Stouthamer and Robert F. Luck
About 70% of all insect species are infected with Wolbachia, a bacterium. Aphytis is no exception. Some Wolbachia infections can be beneficial such as those causing their hosts to produce female offspring exclusively, while others can be negative such as those that affect the efficacy of biological control.
( 197 kb)

Glassy-winged Sharpshooter Impact on Orange Yield, Fruit Size, and Quality Raymond Hix, Mary Lu Arpaia, Carol Lovatt, and Beth Grafton-Cardwell
Prior to this study, it was unknown what impact the glassy-winged sharpshooter had on orange yield, size, and quality as well as tree vigor. The goals of this project were to determine the usefulness of management of GWSS to prevent yield loss, fruit size reduction, and degraded fruit quality.
( 182 kb)

Field Management Plan and Biocontrol Rearing System for Citrus Peelminer David Headrick and Beth Grafton-Cardwell
This project has several objectives: 1) Development of a pheromone-based monitoring system, 2) Development of a degree-day model, 3) Biological control introduction and augmentation, and 4) Development of ArcIMS as a tool to map peelminer infestations.
( 240 kb)

Improving Efficacy of Sterile Insect Technique for Mexican Fruit Fly and Mediterranean Fruit Fly Peter E. A. Teal
During 2004-2005, our research focused on several areas. The first was testing a new gel-based diet developed to take the place of the agar sugar block diet used to feel adult Tephritid flies prior to SIT releases. The second objective was to assess the efficacy of hormone therapy in field cage studies using the Mexican fruit flies. Another area was to determine the effect of incorporation of hormone on male flies held in mass rearing conditions. Finally, we have conducted studies using two
( 108 kb)

Evaluation of Fipronil in Male Annihilation and Ground Treatments for Control of Mediterranean Fruit Fly, Oriental Fruit Fly, and Melon Fly Roger I. Vargas
As part of efforts to register new insecticides for fruit fly control, we tested fipronil in male annihilation treatments for melon fly and oriental fruit fly. We also tested fipronil and several other non-OP insecticides in soil treatments for Mediterranean fruit fly, oriental fruit fly, and melon fly.
( 117 kb)

Evaluation of New Postharvest Treatments to Reduce Postharvest Decays and Improve Fruit Quality in Citrus Packinghouse Operations J. E. Adaskaveg
In the summer of 2005, fludioxonil and pyrimethanil were registered in California following the federal registration in the fall of 2004 for postharvest use on citrus. In September 2005 we successfully placed propiconazole into the federal IR-4 program to establish a residue tolerance for postharvest use, and these studies are planned for 2006.
( 108 kb)

New Methods to Control Postharvest Decay of Citrus Joseph L. Smilanick
The purpose of this project is to develop new methods to control postharvest decay of citrus for use in California packinghouses.
( 156 kb)

Survey of Sensing Methods for Detection of Freeze Damage in Oranges James F. Thompson and David Slaughter
The goal of this project is to develop and test a field method for using an ethanol sensor to measure whether a sample of oranges contains a threshold level of freeze-damaged fruit. The citrus industry is seeking an objective alternative to the manual inspection method used by CDFA inspectors to determine freeze damage in navel oranges.
( 157 kb)

Efficacy of Ozone Combination Treatment to Control Bean Thrips in Navel Oranges James G. Leesch
This research investigates the efficacy of ozone combined with carbon dioxide and vacuum to control bean thrips in navel oranges. A focus of this work in 2004-2005 was effects of wax type and cultivar to mitigate phytotoxic damage.
( 506 kb)

Relationship Between SSC/TA Ratio and Acceptability of Navel Orange Mary Lu Arpaia
This project uses the sensory panel volunteers at the UC Kearney Ag Center to evaluate early season navel oranges with the intent to develop a database of the relationship between SSC/TA ratio, volatiles, and acceptabilty of navel orange fruit. Additionally, during this year we explored the relationship between fruit handling practices, waxes and fruit acceptability following storage.
( 150 kb)

Robotic Mechanical Harvester for Fresh Market Citrus Bret Wallach
The goal of the robot harvester project's second phase, FY2004-2005, was to begin to validate Vision Robotics' concept for mapping orange trees using the scout robot.
( 190 kb)

Improving Postharvest Quality of Stored Lemons Mary Lu Arpaia and Carol J. Lovatt
The goal of this research was to reduce economic losses to the lemon industry due to postharvest decay and to increase postharvest quality and storage life of lemons using the inexpensive naturally-occurring compounds spermidine, spermine and salicylic acid applied as a dip or drench after washing or in the storage wax.
( 194 kb)

Development of Magnetic Resonance for Detection of Freeze Damage in Oranges Michael J. McCarthy
Magnetic Resonance Imaging (MRI) has proven to be a valuable medical diagnostic tool for investigating damage in humans. This tool is useful in medicine since it provides information on "soft tissues" in the body such as muscles and tendons. Our project was focused on developing magnetic resonance for use in detecting damage to "soft tissues" in oranges.
( 134 kb)

Potential Human Perchlorate Exposures from Citrus Irrigated with Contaminated Water Robert I. Krieger and Charles A. Sanchez
Citrus produced in the southwestern United States is often irrigated with perchlorate-contaminated water. Irrigation water may include Colorado River water and ground water from wells in Riverside and San Bernardino counties. Uptake and distribution of perchlorate in citrus irrigated with contaminated water were used to examine potential human exposures from lemon, grapefruit and orange.
( 108 kb)

2004-2005 Assessment Rate, Income and Expenses
An assessment rate of 28 mills (2.80 cents) per standard field box (55 lb. equivalent) was recommended by the Citrus Research Board to the Department of Food and Agriculture for the State of California in order to provide the funds to support 2004-2005 research projects...
( 124 kb)

Citrus Clonal Protection Program Georgios Vidalakis
The California Citrus Clonal Protection Program (CCPP) is a part of the University of California, Riverside, Department of Plant Pathology. The CCPP is a cooperative program with the California Department of Food and Agriculture (CDFA), the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (USDA-APHIS), and the citrus growers of the state of California represented by the Citrus Research Board.
( 138 kb)

California Citrus Quality Council (CCQC) Quality Assurance Program Hugh W. Ewart
As specifically provided for in the California Citrus Improvement Program marketing order, this ongoing Quality Assurance Program is conducted by the California Citrus Quality Council (CCQC) under an operating agreement with the California Citrus Research Board.
( 138 kb)