Citrus Greening Disease

Citrus Greening Disease • Found in FL in August 2005 • Huanglongbing (HLB) – yellow

shoot disease

3/23/2012 2

HLB Tree vs Healthy Tree

Huanglongbing (HLB) background

• The disease has been around since the 19th century

• 1927: Psyllids were first linked to HLB and are the known vector for the disease

• 1998: Asian citrus psyllid was discovered in Florida

• 2005: HLB was confirmed in Florida

• 2010: HLB was confirmed in all citrus-producing counties in Florida

• The level of HLB infection varies widely in the state

3

The Challenges of HLB

• Among most significant challenges to citrus worldwide

• Few solutions available from beyond Florida

• Significant research questions unanswered

• HLB impacts are immediate

• Clearly beyond the scope of the industry’s basal facility to organize, prioritize and fund (2005)

Greening Effects on Citrus Production

• Overall tree decline, eventual tree death

Greening Effects on Citrus Production

• Bitter-tasting, lopsided fruit, small in size • May not color properly with portions

remaining green

Production Costs for a 10+-Year-Old Southwest Florida Processed Orange Grove Source: R.P. Muraro, UF, IFAS

2002-03 Without HLB-

Greening

2009-10 Without HLB &

Black Spot

2009-10 With HLB & Black Spot

$/Acre % $/Acre % $/Acre %

Weed Control & Herbicide 183.13 23.3 185.72 17.2 185.72 11.3

Spray-Pesticide 137.18 17.4 169.10 15.6 482.93 29.4 Fertilizer & Lime-Calcium 152.56 19.4 303.04 28.0 303.04 18.5 Pruning/Topping 28.03 3.6 32.08 3.0 32.088 2.0

Tree Removal/Resets 102.44 13.0 136.72 12.6 276.08 16.8

Irrigation & Ditch Maintenance 184.16 23.3 224.77 20.8 243.17 13.7

HLB Scouting Management & Canker Decontamination 0.00 0.0 29.85 2.8 137.09 8.4

Total Production Costs 787.50 1,081.28 1,641.72

Asian citrus psyllid – Diaphorina citri

First found in Florida June 1998

ASIAN CITRUS PSYLLID Adults

• 3-4 mm in length • may live 30-60+ days • prefer to feed on new leaf flush when present • can survive long periods feeding on undersides of mature leaves • adults infected with HLB bacteria spread pathogen to healthy trees

Psyllid nymphs • 5 nymphal (immature) stages • range in size from 0.3 – 1.6 mm in length • develop exclusively on young tender flush • nymphs are easily observed when populations are increasing during periods of abundant new flush

Eggs • 0.3 mm in length • laid within unfurled leaves • use hand lens to observe • eggs hatch within 3-5 days

Citrus Greening: The Pathogen

• Phloem-limited bacterium • Transmitted by psyllids • Graft transmissible • Not currently cultured

Candidatus Liberibacter asiaticus

Hlb management guidelines • Guidelines are rigorous psyllid control & inoculum removal

• What does it mean for the growers?

– Routinely scouting for psyllids

– Continuously scouting for symptoms of HLB

– Pesticidal suppression of psyllids

– Immediately removing trees confirmed to be infected

11

HLB Increasing Throughout the State October, 2005

2 counties

HLB Increasing Throughout the State April, 2006

12 counties

HLB Increasing Throughout the State January, 2007

14 counties

HLB Increasing Throughout the State June, 2007

24 counties

HLB Increasing Throughout the State February, 2008

30 counties

HLB Increasing Throughout the State August, 2008

32 counties

How Fast Does it Spread? Oct05-Mar06

How Fast Does it Spread? Apr06-Sep06

How Fast Does it Spread? Oct06-Mar07

How Fast Does it Spread? Apr07-Jul07

How Fast Does it Spread? Aug07-Oct07

3/23/2012 23

SGC Groves – Disease Impact

3/23/2012 24

SGC Groves – Disease Impact

3/23/2012 25

SGC Groves – Disease Impact

3/23/2012 26

SGC Groves – Disease Impact

3/23/2012 27

Southern Gardens Citrus Groves - Disease Management

3/23/2012 28

What We Know Today with HLB Management

Growers must Maintain Low Incidence Rates • Inspection • Tree Removal • Psyllid Control • Clean Nursery Stock No Science to support any other practice

3/23/2012 29

HLB Management Positive Trees • Positive HLB Trees Identified 2006 – 2011 = 598,000

• Positive HLB Trees Removed 2006-2011 = 429,000 • Southern Grove

– 350,000 HLB Positive Trees Identified – 169,000 HLB Positive Trees Removed (Grove Sold to SFWMD)

• Dunwody/Alcoma & Devil’s Garden Groves – 248,000 Positive HLB Trees Identified – 248,000 HLB Positive Trees Removed

• Cumulative Infection Rate – All Groves = 24% – Dunwody/Alcoma & Devil’s Garden Groves = 23%

Why the urgency?

3/23/2012 30

Assumptions: Starting production 150M boxes/yr Starting trees 60 million Nursery capacity 3.5 M/yr Production loss 5%/year Starting infection 18% % of Nursery reached 55% Infection rate 1.25X per year

Why the urgency?

3/23/2012 31

Assumptions: Starting production 150M boxes/yr Starting trees 60 million Nursery capacity 3.5 M/yr Production loss 5%/year Starting infection 18% % of Nursery reached 55% Infection rate 1.25X per year

Aerial Applicator

Injection Applicator

Ground Airblast Sprayer

Low Volume Sprayer

Precision Spray Applicator

HLB Survey Crew

• Severely Infected Tree

• Solid Block Before HLB

• Same Block After Inoculum Removal

• Severely Infected Block

Serenade Max WP 2.25 lb/a $11.75/lb $26.44

Oxidate 2 qt/a $32.00/gal $16.00

14-7-8 w/Kphite 8 gal/a $8.05/gal $64.40

Potassium Nitrate 8.5 lb/a $0.58/lb $4.93

Manganese Sulfate 8.5 lb/a $0.91/lb $7.73

Magnesium Sulfate 8.5 lb/a $0.29/lb $2.47

Zinc Sulfate 2.8 lb/a $0.92/lb $2.58

Sodium Molybdate .85 oz/a $1.51/oz $1.28

Saver 1 qt/a $22.00/gal $5.50

435 Oil 5 gal/a $4.50/gal $22.50

Aggressive Nutritional Program

Total Cost per Application $153.83 Total Annual Cost (4 x’s) $ 615.32

Increased Production Cost Due to HLB

PSYLLID CONTROL Cost Per Acre

Admire Injections 6 @ $15 $90.00 Additional Ground Sprays 2 @ $32 $64.00

Arial Sprays 5 @ $23 $115.00 Additional Insecticides 4 @ $10 $40.00

TREE HEALTH Nutritionals $250 - $500 $375.00

ROOT HEALTH Ridomil Applications 2 @ $45 $90.00

HLB CONTROL Surveys 3 @ $25 $75.00

Tree Removal 3 @ $10 $30.00

SUBTOTAL $879.00

Tree Loss 5% $150.00

Fruit Loss 2% $60.00

SUBTOTAL $210.00

Reduction of Income Per Acre Due to HLB $1,089.00

Loss of Income Due to HLB

Questions / Discussion?