Hero Image

Contact Us

UC Cooperative Extension Ventura County
669 County Square Dr. Suite 100
Ventura CA 93003
Phone: 805.645.1451
Fax: 805.645.1474

Office Hours
Our offices are currently closed due to the COVID-19 pandemic, and our team is telecommuting from home. We are available via phone and email. 

Click here for our office directory: Contact/Staff Info

 

Topics in Subtropics

The U.C. Cooperative Extension Farm Advisors have combined to publish this quarterly combined newsletter. It will emphasize citrus and avocado, but will also discuss the minor subtropicals.

Issue Articles Type Date Added
Topics in Subtropics v. 18 - Spring 2020

Our numbering got off, but we're back on track. Welcome to v. 18 of Topics in Subtropics, Spring 2020.

 

TOPICS IN THIS ISSUE – Ben Faber, Editor

  • An Automated Delivery System for Therapeutic Materials to Treat HLB Infected Citrus
  • On-Farm Research
  • Citrus Dry Root Rot
  • Beth Grafton-Cardwell to Retire

ANNOUNCEMENTS:

  • What are the UC Ag Experts Talking About?
  • Memorial to Dr. Travis Bean
PDF 6/17/20
Topics in Subtropics, Volume 22, Winter 2020

In this issue:

  • Rattlesnakes in California Orchards
  • What’s the Fuss Over Spotted Lantern Fly?
  • Frost Freeze Recovery from February 2020
  • Covid Virus Resources
  • New Guidelines for Laurel Wilt Disease
PDF 4/6/20
Volume 21, Fall 2019

In this issue ...

Leveraging the Genomic Landscape of Avocado for Breeding Purposes (Vanessa Ashworth and Philippe Rolshausen)


Fresh Market Raspberry in California (Natalie Solares and Alexander Putman)


Weed Management in Citrus Orchards (Travis Bean)

PDF 12/2/19
Topics in the Subtropics Vol 20 Summer 2019

Topics in this issue:

  • A “boring” problem that’s generating a big interest in southern California
  • How ants can be “good” in ag production systems
  • Is Eucalyptus a Safe Material for Mulching Trees?
  • Botryosphaeria Gummosis and Dieback of Citrus
  • The online Lucid Key, Thrips of California, has been updated
PDF 8/6/19
Topics in the Subtropics Vol 19 Spring 2019

In this issue:

  • Introducing Your New Information Source for CDFA grants, Kern and Ventura Counties
  • Spotlight on SWEEP in Citrus
  • Low Pressure Guide to Low-Flow Irrigation Scheduling
  • The So-Called “Leaf Fleck” Virus Diseases of Citrus
  • Replanting Trees in Mature Citrus Groves
  • What about Planting Lemons in Kern County?
PDF 5/7/19
Topics in the Subtropics Vol 18 Winter 2019

In this Issue:

  • Distinguishing Between Symptoms of Drought and Root Rot in Avocado
  • Avocado Trunk Cankers
  • Viruses Are Our Friends-and Maybe for Citrus Too
  • Ground Squirrel and Other Vertebrate
    Control
  • Meet our new Citrus Specialist at UC
    Riverside/Lindcove
  • Meet our new Extension Tree Crops Spray
    Application Engineer
  • UC Ag Experts Talk
PDF 3/22/19
Topics in Subtropics News Letter - Fall 2018

Volume 17, Fall 2018

A new issue of Topics in Subtropics in available.

In this issue:

  • California Citrus Network - an online forum to facilitate communication
  • High Density Planting for Avocado
  • Meet the new UC Riverside subtropical crops specialist

 

PDF 11/8/18
Topics in Subtropics - Volume 17 - Summer 2018

TOPICS IN THIS ISSUE

• Native Pollinators of California Avocado as Affected by Introduced Pollinator Gardens
• Which Way World Avocados?
• Evaluating Cost Effectiveness of High Density Planting of Avocados: Experiment on Water and Pruning
• Herbicide injury in avocados

PDF 9/26/18
Topics in Subtropics - Volume 17, Spring 2018

In this Issue:

  • A Taste of Coffee
  • Colletotrichum Shoot Dieback: A New Disease of California Citrus
  • Successfully Irrigating Potted Trees
  • Update on Huanglongbing Disease in California Citrus
PDF 5/8/18
Winter 2018 Topics in Subtropics
  • South American Palm Weevil Threat
  • Template to Estimate the Value of Tree Loss
  • After the Fire and Before the Rain - What to Do
PDF 2/26/18
Fall 2017
  • Ah, Rats! ?
  • So You Want To Install Soil Moisture Meters? ?
  • Notes on Applying Gibberellic Acid (GA) to Navels in
    the Southern San Joaquin Valley of California ?
  • Fall Leaf Tissue Sampling ?
  • FREE!  Citrus:  UC IPM Pest Management  Guidelines
PDF 10/11/17
June - July Topics in Subtropics 2017

TOPICS IN THIS ISSUE:
 
•  Why has California red scale been so difficult to control? 
 
• Navel Orange Nitrogen Fertilization
• Recent Advances in Understanding the History of
Olive Domestication
• Upcoming UC Olive Center Events

PDF 6/20/17
January - March Topics in Subtropics 2017

In this issue:

  • Revisiting an old study
  • Shoot and Twig Dieback
  • Alternative Crops
  • Referendum Comments
PDF 3/1/17
Volume 14 No. 4, November 2016
  • Real-Time Sensor for Early Detection of Citrus Huanglongbing (HLB)
  • The 2016 International Citrus Conference
  • UC Riverside Scientists Evaluate Trunk Injections of Pesticides for The Management of Ambrosia Beetles in California Avocados
  • An Overview of Mango
  • Water Based Latex Paint as a Means to Track Ambrosia Beetle Activity on Infested Trees
PDF 12/8/16
Volume 14 No. 2 June 2016

TOPICS IN THIS ISSUE:

• “We Shall Defend our Citrus, We Shall Fight in Backyards and Community Gardens, We Shall Fight in Organic and Conventional Citrus Orchards; We Shall Never Surrender.”

• Organic Control of Asian Citrus Psyllid is Challenging

• Citrus Clonal Protection Program (CCPP) and National Clean Plant Network (NCPN): A Model System for Management of Citrus Diseases

• Discouraging citrus varieties smuggling by offering easy access to pathogen-tested budwood

DOCX 8/2/16
Topics in Subtropics, Volume 14, Number 1, January - March 2016

TOPICS IN THIS ISSUE:

 

Avocado Cultivars

Botanical Races and Genetic Footprints

Drought Induced Problems in Our Orchards

PDF 4/14/16
Volume 13, Number 4

Blossom End Rot of Citrus

Using Organic Herbicides in Production Fields and Non-Crop Areas

Pocket Gopher and Ground Squirrel Control: Management Options for Citrus and Avocado Groves

 

PDF 3/3/16
Topics in Subtropics Fall 2015 Edition

In this issue:

  • Predicting water usage along the coast versus in the valley
  • Avocado Farms - what we have learned about fire readiness
  • Olive Oil Quality

 

DOCX 9/9/15
Summer 2015 Volume 13 Number 2

IN THIS ISSUE:

 

INTRODUCTION AND NEW RESEARCH

 

  • Did a Newly Introduced Fukumoto Navel Budline from Spain Perform Better than the California Budline in the San Joaquin Valley?

 

  • What values should olive growers use for estimating crop nitrogen removal at harvest?

 

UPCOMING COURSES

 

  • UC Davis Olive Center: UC Master Milling Certificate Course

 

AUTHORS IN THIS ISSUE

 

Craig E. Kallsen University of California Cooperative Extension, Kern County

Neil V. O’Connell, University of California Cooperative Extension, Tulare County

Georgios Vidalakis, University of California, Riverside, Extension Specialist & Plant Pathologist, Director-Citrus Clonal Protection Program (CCPP)

Elizabeth J. Fichtner, Farm Advisor, UCCE Tulare County

PDF 6/22/15
Volume 13 No. 1 February - April, 2015 PDF 4/1/15
Volume 12 No. 3 September-December 2014

In this issue:

  • The Clegg Collection: A Valuable Resource
  • Impacts of the recent drought conditions on Central Coast avocado production, and potential impacts of continued drought conditions
  • Zinc and Phosphorus
  • Recent findings on polyphagous shot hole borer/Fusarium dieback on avocado
PDF 12/8/14
Vol. 12 No. 2, Spring (April-June) 2014

In this issue:

  • Vole Damage to Citrus
  • Time to Go Fishing!
  • 'Meyer' Lemon and C-35 Citrange Rootstock
  • Are Hops a Serious Option for a Crop in San Diego County?
PDF 8/6/14
Vol. 12, No. 1, Winter 2014 (Jan-Mar)
  • The Spanish Avocado Industry
  • Strategizing for Water Cutbacks - Avocado and Citrus
  • California Agricultural Production Statistics
  • Maintaining the Citrus Orchard with a Reduced Irrigation Allotment
  • The 2014 Drought in California
PDF 4/9/14
Vol. 11, No. 4, November-December 2013
  • Rehabilitating Frost Damages Citrus and Avocado
  • Advances in mitigation of alternate bearing of olive: vegetative growth response to plant growth regulators
  • Fertigation - Measuring Uniformity
  • Olive Fly Update
PDF 12/19/13
Vol. 11, No. 3, Sept 2013

In this issue:

  • Olive Tree Phenology
  • Training and Pruning of Cherimoya
  • High Density Avocado Installation:  Use a quick cost study to make a decision
  • Volatile Organic Compound (VOC) Emissions from Pesticides
PDF 10/17/13
Vol. 11, No. 2, Spring 2013

In this Issue:

  • Cultural Practices to Reduce Pest and Disease in Avocado and Citrus
  • Polyphagous Shot Hole Borer in California
  • Electronic "sniffer" for Detecting HLB
  • Important Information Sources related to Fire Management and Protection
  • Be Kill in Oregon - A Reminder of Pesticide Use
PDF 7/12/13
Vol. 11, No. 1, March 2013

In this issue:

  • Costs of Orchard Establishment and Production Summary for Avocados in California
  • Huanglongbing Conference, Florida
  • Going Out of Business in the Citrus Business -- Doing it the Right Way
  • The Avocado:  Botany, Production and Used, 2nd Edition
  • Winter Irrigation
  • Update from Israel on the Polyphagous Shot Hole Borer and Fusarium symbiont 

 

PDF 3/25/13
Vol.10, No.3, Fall 2012
  • Asian Citrus Psyllid Quarantines
  • Decline of Oranges and Mandarins
  • Mitigation of Alternate Bearing in Olive
  • Alternate Bearing in Mandarin
PDF 12/20/12
Vol. 10, No. 2 -- Summer 2012

This issue contains the following articles:

  • Simazine Degradation in CA Citrus Orchards
  • Lime-induced Iron Chlorosis
  • Avocado Trunk Cankers
  • Asphyxiation
  • Tree Wraps
  • Stem and Leaf Blight
PDF 9/19/12
Vol. 10 No. 1 -- Spring 2012

This issue of Topics in Subtropics contains the following articles:

  • Quarantine for Huanglongbing Declared in Hacienda Heights Section of Los Angeles County
  • An Outline of Management Options for HLB in Florida
  • Avocado Farming with High Priced Water
  • Soil Moisture Sensors
PDF 6/6/12
Hope for Citrus

Please see attached blurb regarding promising research in the fight against the ACP-HLB pest disease complex.

PDF 4/10/12
Volume 9 No. 2 -- Winter 2011

This issue of Topics in Subtropics contains the following articles:

  • Vertebrate Damage
  • Chemical Thinning of Olives
  • Tips on Producing the Earliest Early Citrus in the San Joaquin Valley
  • Herbicide Registration Chart
  • Resource and Market Information for Enterprise Selection
PDF 1/10/12
A Frost Primer
  • Definitions
  • Gauging Wind Speed
PDF 11/22/11
Protecting Subtropical Fruit Trees from Frost
  • How Frosts and Freezes Occur
  • General Cultural Practices
  • Managing Irrigation Water for Tree Protection
  • Use of Wind Machines
  • Ice-nucleating Bacteria
PDF 11/22/11
Volume 9, No 1 - March - June 2011
  • Organic Herbicides:  Do they work?
  • Snake Oil:  Horticultural Myths and Legends
  • Success Story before There Is a Problem
PDF 9/13/11
Volume 8, No.3 - July-September 2010
  • An update on the threat of Asian citrus psyllid and Huanglongbing for citrus
  • The Search for Salinity Tolerance in Avocado: An Update on a Frozen Rootstock Trial
  • Activator Spray Adjuvant Selection: Crop Spraying
  • Conservation Programs Deadline Set for 2011 Funding: NRCS-Natural Resources Conservation Services News Release
PDF 8/22/11
Volume 8, No.2 -- May 2010
  • NRCS Announces Initiative to Improve Agricultural Energy Efficiency
  • Periwinkle Provides Ammunition In The War On Citrus Plague
  • Do we really need Scientific Irrigation Scheduling?
  • Farmers Should Make A Skin Check a Priority
  • Feeding Habits of California Ground Squirrels and their Role in Management
  • Squirrel Calendar - 'English
  • Squirrel Calendar - Spanish
    PDF  
    Volume 8, No.1 -- December-March 2010
    • Microirrigation, Fertilizers and Clogging
    • Chemical Treatment to Prevent System Clogging
    • Cultural Practices to Reduce Pest and Disease in Avocado and Citrus
    • Larurel Wilt Update
    • The Parent Washington navel orange tree--Part 2. Its decline and recovery
    PDF  
    Volume 7, No.4 - October-December 2009
    • The state of Dothiorella Canker on Avocado in California
    • The Parent Washington navel orange tree - It's first yearsvChester N Roistacher Retired Citrus Virologist, University of California, Riverside
    • Mechanical Harvesting of California Table and Oil Olives
    PDF  
    Volume 7,No.3--July-September 2009
    • 'Valentine,' A Recently Released Anthocyanin-pigmented Pummelo Hybrid Developed at the University of California Riverside
    • The University of California-Riverside Citrus Variety Collection and Citrus Clonal Protection Program Websites Provide Information, Photographs, Fruid Quality Data and More
    • Water Infiltration Problems
    • Attention San Joaquin Valley Citrus Growers: What Do You Plan to Do If It Comes For You?
    PDF  
    Volume 7. No.2 -- April-June 2009
    • Ag Waivers for San Diego County
    • Spray Adjuvants; what's in a Name?
    • Strategizing for Water Cutbacks - Is there a Logical Method?
    PDF  
    Volume 7, No. 1 - Winter 2009
    • Avocado Research in Ventura County
    • Laurel Wilt Disease Conference and Tour in Florida and Georgia
    • Managing Insecticide Resistance will be Key to the Future of Effective Citrus Pest Management
    • Smart Sprayers Make Sense
    PDF  
    Volume 6, No. 4 - Fall 2008
    • Dothiorella Leaf and Stem Blight
    • Irrigation Stress and Early-Navel Fruit Maturity
    PDF  
    Volume 6. No. 3 - Summer 2008
    • New Registration for the Biocontrol Plantshield HC Against Hyphoderma Gummosis of Citrus
    • Atmometers for Irrigation Management
    • Asian Citrus Psyllid has Arrived in San Diego County
    PDF  
    Volume 6, No.1 January-March 2008
    • Evaluation of Insecticides for Citrus Thrips Control, Using Blueberries as a Crop Surrogate
    • The Silver Mite Workgroup
    • Just Because Spring is a Good Time to Prune Navel Orange Dosesn't Mean You Should
    • Brevipalpus Mites and Citrus Leprosis Virus Disease
    PDF  
    Volume 5, No.4 Fall 2007
    • Grower Cooperators Deserve Recognition for Service to Their Industries
    • Citrus Leaf Miner Update
    • Stubborn Disease of Citrus in California
    • New Avocado Publication
    PDF  
    Volume 5, No.3 July-September 2007
    • Leaf Analysis
    • Citrus Leafminer Update
    • Are all Phosphorous Products the Same
    • Financial Statements and Ratios
    PDF  
    Volume 5, No. 2--April-June 2007
    • Update on Lychee and Longan Fild Trials and Plantings in Southern California
    • Loopers in Avocados--A Note from San Diego County
    • The 2007 Citrus Tristeza Virus Situation at the University of California Lindcove Research and Extension Center
    • Errata: Honey Bees in California
    PDF  
    Volume 5, no. 1 -- Jan-March 2007
    • An Introduction to the Problem of Honey Bees and Mandarins
    • Birds do it; Bees do it, Even Citrus with Seeds do (did) it. Part1-The Biology Behind Seedlessness in Mandarins
    • Honey Bees in California
    PDF  
    Rehabilitation of Freeze-Damaged Citrus and Avocado Trees This is not a newsletter, however, I thought you could use the information. Ben Faber PDF  
    Living with Fire This is not a newsletter, it is information about caring for fire damaged trees. PDF  
    Volume 4, No. 4 -- October-December 2006
    • Boron is High in Many Southern San Joaquin Valley Citrus Trees
    • Armillaria Root Rot
    • Soil Test Kits
    • Using Evapotranspiration (ETo) for Scheduling Irrigations-An Improvement on "Guessing"
    • Subtropical Crops Program Coverage in Riverside County
    PDF  
    Volume 4, No. 3 - July - September 2006
    • The Positive Points Systems for Citrus: What is it and Why Should a Grower Get Involved
    • Getting Horseweed and Hairy Fleabane Back Under Control in Central California
    • A Comparison of the New "Sequoia" Fig Cultivar
    • A Celebration of Agricultural Research&Extension
    PDF  
    Volume 4, No. 2 - April-June 2006
    • Citrus Research Growers' Seminars 2006
    • Dry Rot in Citrus
    • Earwigs Flying Under the Radar of Many Citrus Pest Control Advisors
    • New Tools Available for Spider Mite Management in 2006
    • Product Testing
    PDF  
    Volume 4, No. 1 - January-March 2006
    • Liquid-Sugar Ant Bait Stations are Nearing Registration for Agriculture
    • Huanglongbing, Citrus Greening: Preparing For the Future
    • Citrus Herbicide Charts&Tables Kurt Hembree/Farm Advisor, Fresno County
    • Bear Citrus Thrips Resistance in Mind When Deciding Whether&How to Treat in 2006
    PDF  
    Volume 3, No.4--September-December 2005
    • Management of Banks Grass Mite in Dates
    • UC Riverside Citrus Variety Collection
    • Diapres Root Weevil Infestations Found in Southern California a Recent Exotic Pest Invasion
    • Diaprepes Quarantine Details
    PDF  
    Volume 3 No. 3 - July-August-September 2005
    • Little Evidence to Support the Use of Foliar Applied Nutrients in Avocado
    • Web Sites That Can Help Your Production
    • Cutoff Deadline Set for Landowners Applying for 2006 EQIP Funds
    • Intensive Training Course on "How to Export Your Food or Agricultural Product"
    • Cal/OSHA Heat Advisory
    PDF  
    Volume 3 No.2 - April May June 2005
    • Citrus Leafminer, New Pest for Southern California
    • Ag Waivers
    • Super-Early--Season Satsuma Mandarins for San Joaquin Valley and California
    • Protecting Workers From Heat Strees
    PDF  
    Volume 3 No.1 - January February March 2005
    • Phosphorous Acid in Avocado Production Should it be a Cultural Recommendation
    • Emergency Farm Loans
    • New 24C Registration of Isopropyl Ester 2,4-D (Alco Citrus Fix) for Fruit Size Increase of Mandarins and Mandarin Hybrids in California
    • Asphyxiation
    • Dweet Mottle Virus and Citrus Leaf Blotch Virus
    PDF  
    Volume2, No.4--October-December 2004
    • Upcoming Meetings
    • Avocado Lace Bug
    • The First Rule of Growing Citrus in the San Joaquin Valley: Location, Location, Location
    • The Inland Empire Small Farm Inititative: Promoting Small Farm and Hispanic Economic Development in Riverside and San Bernardino Counties
    • Cellulase Production by Various Sources of Mulch
    PDF  
    Volume 2, No.3 -- July-September 2004
    • Upcoming Meetings
    • Deficit Irrigation
    • Topworking or Replanting-A Grower's Perspective
    PDF  
    Volume 2, No.2--April-June 2004
    • Upcoming Meetings
    • Mechanical Pruning and Harvesting Olives
    • One, One Hundred, One Thousand
    • Making Sense of Soil Moisture Checking and Sensors
    • Think Twice Before Planting Clementine and W.Murcott Afourer Mandarins
    PDF  
    Volume 2, No.1 -- January-March 2004
    • UC Publications&Meetings
    • Verteberate Pests Causing Damage in Citrus
    • After the Fire in the Avocado Grove--Replant or Sucker Graft
    • Compatibility/Seediness Among Clementine Mandarins....
    • Irrigation Scheduling
    • An Update of Agricultural Waivers in CA--Water Quality Programs for Irrigated Agriculture
    • Integrating Admire Treatments for GWSS with Citrus IPM in the San Joaquin Valley
    PDF  
    Volume 1 No.4--October - December 2003
    • Irrigation on Slopes
    • Pollination & Seeding of Clementines
    • Weed Control Practices and Costs
    • Farm Mapping
    • Calculating Value of Tree Loss
    • Nick Sakovich Retires
    • USDA Emergency Loans for Fire Losses
    • Educational Opportunities
    PDF  
    Volume 1 No.3--July-September, 2003
    • Citrus Fall Tissue Sampling
    • Invasive species
    • Avocado Planting Holes
    • Production Quiz
    • Puncture Vine
    • Avocado Rootstocks
    • Charlie Coggins Scholarship Fund
    PDF  
    Volume 1 No.2 -- April-June, 2003
    • Who are We
    • Citrus Leafminer
    • Medjool Dates
    • Pruning Avocado
    • Dry Root Rot of Citrus
    • Upcoming Meetings
    • UC Farm Advisor Listing
    PDF  
    Volume1 No. 1 - January, February, March 2003
    • The Mexican Fruit Fly Quarantine...A Caution for All Growers in California
    • Lychee and Longan--New Crops for California
    • Bees and Mandarins--The New Range War
    • Resource and Market Information for Enterprise Selection
    • A Message from Dr. France Cordova, Chancellor at UC Riverside
    PDF