Protect Lemons, Limes and Orange Trees from Greening Disease Using the Texas Model

By Dr. Mani Skaria, Professor Emeritus of Plant Pathology, Texas A&M University-Kingsville

The Florida citrus industry lost 75% of its production to greening disease (HLB). Over $250 million was spent on research with no practical solutions for growers. Meanwhile, the first HLB-infected orchard in Texas became one of the most profitable citrus farms in the county.

What's the difference? The Texas Model focuses on tree health instead of chasing the disease. After 40 years studying citrus diseases and growing over 250,000 trees at our South Texas nursery, I've learned that healthy trees can coexist with HLB and still produce profitable crops.

This isn't theory from a laboratory. This is real-world proof from commercial orchards that turned HLB infection into higher profits.

Key Takeaways

• The Texas Model prioritizes overall tree health over disease elimination
• Healthy root systems are essential for HLB tolerance and survival
• Copper-contaminated soil in Florida limits root performance and HLB resistance
• Micro-budded, high-density planting accelerates fruit production and profitability
• Practical field solutions work better than laboratory-based research approaches

What Is Greening Disease and Why Does It Matter?

Greening disease (Huanglongbing or HLB) is caused by bacteria spread by the Asian citrus psyllid. The disease was first found in Florida in August 2005 and has devastated the state's citrus industry.

Here's what makes HLB so destructive:

• Trees produce bitter, misshapen fruit that drops early
• Leaves turn yellow in a blotchy pattern (not uniform yellowing)
• Root systems deteriorate, weakening the entire tree
• Trees eventually die without proper management
• No cure exists once a tree is infected

The bacteria clogs the tree's vascular system, preventing nutrients and water from moving properly. Think of it like a heart attack for your citrus tree.

Why Has Florida Lost 75% of Its Citrus Industry to HLB?

Florida's approach focused on eliminating the disease rather than building tree health. Between 2005 and 2017, over $250 million was spent on research. The result? Tons of scientific papers but no practical solutions for growers.

Here's what went wrong in Florida:

Research Problems

• Scientists were rewarded for publishing papers, not solving grower problems
• Most research happened in comfortable laboratories, not hot, humid farms
• Specialists studied narrow topics instead of whole-tree health
• Smart grower observations were ignored in favor of academic theories

Environmental Challenges

• Florida's humid climate favors the psyllid vector
• Hurricanes spread the disease and vector across long distances
• Asian jasmine (a common landscape plant) hosts both the bacteria and psyllid
• Copper-contaminated soil from years of fungicide sprays damages feeder roots

Regulatory Delays

• HLB bacteria were classified as "select agents" for bioterrorism concerns
• This created 36 months of research delays and regulatory restrictions
• Critical early intervention time was lost to bureaucracy

How Does the Texas Model Protect Citrus Trees from HLB?

The Texas Model takes a completely different approach. Instead of trying to eliminate HLB, we focus on building tree health so trees can tolerate the disease and remain profitable.

The Texas Success Story

On Friday the 13th, January 2012, HLB was first found in a commercial orchard in San Juan, Texas. Scientists predicted doom for the family business. I advised the grower to ignore the panic and focus on tree health and psyllid management.

The result? That orchard is now one of the best-producing citrus farms in Hidalgo County. In 2015, the grower sent me a thank-you email acknowledging that focusing on tree health worked.

Florida scientists visit our Hargill, Texas operations regularly to see this "impossible" success story with their own eyes.

Core Principles of the Texas Model

1. Root Health Comes First

Healthy roots equal healthy plants. Trees with strong root systems can tolerate HLB infection and continue producing quality fruit. This means:

• Using mineral-based soil that provides permanent aeration
• Avoiding copper-contaminated soils that damage feeder roots
• Supporting root health with beneficial microbes

2. Whole-Tree Health Approach

Instead of targeting just the disease, we support the entire tree system:

• Proper nutrition with organic, slow-release fertilizers
• Balanced soil biology with live microorganisms
• Stress reduction through optimal growing conditions

3. Practical Field Solutions

We test everything in real commercial orchards, not laboratories:

• Micro-budded trees that fruit faster and generate quicker returns
• Higher-density planting for maximum production per acre
• Integrated pest management for psyllid control

What Makes Texas Trees More HLB-Tolerant Than Florida Trees?

Better Soil Conditions

Texas citrus is grown in mineral-based soils that provide excellent drainage and aeration. Florida's copper-contaminated soils from decades of fungicide applications damage the fine feeder roots that trees need to absorb nutrients.

Copper toxicity creates the same symptoms as HLB infection. We proved this at our demonstration plots in Weslaco, Texas, where excess copper applications mimicked HLB symptoms exactly.

Focus on Tree Health, Not Disease Elimination

A well-known Florida grower with a chemistry background started making more money after HLB arrived in his groves. Why? He began paying attention to complete tree health for the first time.

His success came from supporting both root and shoot systems with proper nutrition and soil management. His banker, fruit packer, and bottom line all confirmed the results, even though academic scientists dismissed his methods as "unscientific."

Micro-Budded, High-Density Systems

Our micro-budded trees (a technique I invented) produce fruit faster than traditional grafted trees. This means:

• Quicker return on investment
• Higher production per acre
• Better economics even with HLB present
• Reduced time to profitability

State Senator Juan "Chuy" Hinojosa visited our operations in June 2018 and saw firsthand how micro-budded trees in high-density plantings produce commercial fruit faster than anyone thought possible.

Why Genetic Modification Won't Save the Citrus Industry

While researchers work on GMO solutions like the spinach gene for HLB resistance, these approaches face major economic hurdles:

Market Acceptance Issues

• Consumer resistance to genetically modified fruit
• Export market restrictions for GMO products
• Potential marketing disasters from negative publicity

Economic Reality

• Citrus trees are perennial crops with high upfront costs
• Profits are recovered over many years of production
• One negative report about GMO citrus could destroy market demand
• The financial risk is too high for commercial growers

Better Alternatives Exist

The Texas Model proves you can achieve HLB tolerance through natural tree health practices without genetic modification risks.

How to Apply the Texas Model to Your Citrus Trees

Step 1: Build Healthy Root Systems

Healthy roots are your tree's foundation for HLB tolerance. Here's how to establish them:

Use Mineral-Based Soil

• Choose soil that never decomposes (sand, perlite, rock-based materials)
• Avoid organic potting mix that suffocates roots as it breaks down
• Ensure excellent drainage to prevent root rot
• Maintain soil pH around 6.0 for optimal nutrient uptake

Support Soil Biology

• Add beneficial microbes that protect roots and improve nutrient uptake
• Use organic fertilizers that work with soil biology instead of against it
• Avoid synthetic fertilizers that kill beneficial microorganisms

Step 2: Provide Complete Nutrition

Essential Nutrients for HLB Tolerance:

Nutrient	Function	Deficiency Signs
Nitrogen	Leaf growth, green color	Yellow leaves, poor growth
Phosphorus	Root development, flowering	Purple leaves, poor fruiting
Potassium	Disease resistance, fruit quality	Brown leaf edges, small fruit
Calcium	Cell wall strength	Bitter pit, weak branches
Magnesium	Chlorophyll production	Yellow between leaf veins
Iron	Chlorophyll synthesis	Yellow leaves with green veins

Fertilization Schedule:

• Apply organic, slow-release fertilizer monthly during growing season
• Use formulations with all 12 essential nutrients
• Avoid high-salt synthetic fertilizers that damage roots

Step 3: Manage Psyllids Without Destroying Beneficial Insects

Psyllid management is important, but it's not the whole solution. Focus on:

Monitoring and Early Detection

• Check new growth weekly for psyllid eggs and nymphs
• Look for waxy, white egg masses on young leaves
• Watch for honeydew (sticky secretions) on leaves

Selective Control Methods

• Use horticultural oils that suffocate psyllids without harming beneficials
• Apply insecticidal soaps for soft-bodied pests
• Encourage natural predators like ladybugs and lacewings
• Remove heavily infested shoots and dispose of them

Step 4: Choose the Right Tree Varieties

Some citrus varieties show better HLB tolerance:

More Tolerant Varieties:

• Persian (Bearss) Lime - vigorous growth, good production
• Pummelos and pomelos - larger trees with stronger root systems
• Some mandarin varieties - faster growing, earlier production

Varieties Needing Extra Care:

• Sweet oranges - more susceptible to HLB damage
• Meyer Lemons - require excellent root health
• Grapefruit - slower to establish, needs optimal conditions

What Can Home Growers Learn from the Texas Model?

You don't need a commercial orchard to apply Texas Model principles. Here's how home growers can protect their citrus trees:

Container Growing Tips

Soil Selection:

• Use mineral-based potting soil, never organic potting mix
• Ensure containers have excellent drainage holes
• Choose containers at least 20 gallons for mature trees

Nutrition Program:

• Feed monthly with complete organic fertilizer
• Add beneficial microbes to support root health
• Monitor for nutrient deficiency symptoms

Psyllid Management:

• Inspect trees weekly, especially new growth
• Remove affected shoots immediately
• Use sticky traps to monitor psyllid populations
• Apply horticultural oil sprays when needed

Landscape Growing Tips

Site Selection:

• Choose well-draining locations
• Avoid low spots where water collects
• Provide protection from strong winds
• Ensure 6+ hours of direct sunlight

Soil Preparation:

• Test soil drainage before planting
• Improve heavy clay soils with sand and organic matter
• Avoid areas with copper contamination from old fungicide use
• Plant on raised beds if drainage is poor

Why the Research Community Needs to Change Direction

After 34 years in university research and 18 years as a commercial grower, I've seen what works and what doesn't. The current research approach needs major changes:

Problems with Current Research

1. Publication Pressure - Scientists are rewarded for publishing papers, not solving grower problems
2. Laboratory Focus - Too much research happens in controlled environments, not real farms
3. Specialist Mentality - Researchers study narrow topics instead of whole-system health
4. Grower Disconnect - Academic scientists ignore practical observations from successful growers

What Needs to Change

Research Priorities:

• Focus on practical, field-tested solutions
• Evaluate scientists based on grower impact, not just publications
• Give researchers 3-4 year release time from publication requirements
• Emphasize systems approaches over single-factor studies

Grower Involvement:

• Include successful growers in research planning
• Test all solutions in commercial orchards
• Value practical results over theoretical models
• Learn from growers who are already successful with HLB

The Four Pillars of Florida's Recovery Through Texas

Florida's citrus industry can recover using lessons learned in Texas. Here are the four pillars:

Pillar 1: Technology Transfer from Texas

When US Sugar Company needed GMO solutions for HLB, they came to Texas A&M AgriLife Research in Weslaco. The solutions they need are already being developed here.

Pillar 2: Proven HLB Tolerance in Commercial Production

Our first HLB-infected orchard in Texas is now one of the county's best-producing farms. This proves HLB tolerance is achievable in commercial operations.

Pillar 3: Understanding Copper Toxicity

Our research at Texas A&M University-Kingsville shows that copper contamination creates HLB-like symptoms. Florida's copper-contaminated soils may be causing more damage than the disease itself.

Pillar 4: Micro-Budded, High-Density Systems

Our all-natural production methods using micro-budded trees and higher-density planting create profitability faster, offsetting HLB's economic impact.

Historical Lessons: Learning from Past Citrus Challenges

The citrus industry has overcome major challenges before. We can learn from how we handled:

Citrus Blight (100+ Year Problem)

• Focused on tree health and root system management
• Developed resistant rootstocks through traditional breeding
• Used cultural practices to reduce disease pressure
• Created profitable production systems despite the disease

Citrus Canker Eradication

• Coordinated effort between researchers, regulators, and growers
• Clear action plans with measurable goals
• Adequate funding for practical solutions
• Focus on results, not just research publications

Early HLB Response (2005-2008)

• Initial panic led to poor decision-making
• Regulatory delays cost valuable time
• Lack of coordination between agencies and growers
• Too much focus on elimination, not management

Moving Forward: A Systems Approach to HLB Management

The future of citrus production with HLB requires a complete systems approach:

Immediate Actions Needed

1. Redirect Research Focus - Emphasize practical, field-tested solutions over laboratory studies
2. Support Successful Growers - Learn from growers who are already profitable with HLB
3. Improve Soil Health - Address copper contamination and root health issues
4. Technology Transfer - Share Texas Model successes with other citrus regions
5. Grower Education - Train growers in whole-tree health management

Long-Term Strategy

Research Integration:

• Combine university research with commercial grower experience
• Focus on systems approaches rather than single-factor studies
• Evaluate success based on grower profitability, not just publications

Industry Transformation:

• Shift from disease elimination to disease tolerance
• Adopt micro-budded, high-density production systems
• Implement comprehensive tree health programs
• Build soil biology and root health as the foundation

Ready to Protect Your Citrus Trees with the Texas Model?

The Texas Model proves that citrus trees can survive and thrive even with HLB present. The key is building unshakeable tree health through proper soil, nutrition, and root care.

At US Citrus Nursery, our trees are grown using these same Texas Model principles. Every tree starts with healthy roots in mineral-based soil and gets the complete nutrition program that creates HLB tolerance.

Browse our citrus trees grown with Texas Model methods, or learn more about the soil and nutrition products that make the difference between tree failure and tree success.

Your citrus trees deserve the same health foundation that's keeping Texas orchards profitable despite HLB. Give them that advantage from day one.