Asian citrus psyllid & the citrus disease huanglongbing: Training for retail nurseries - PowerPoint Presentation

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Asian citrus psyllid & the citrus disease huanglongbing: Training for retail nurseries and garden centers

Psyllid

Huanglongbing

Photography: M. Rogers, M. Keremane, S. Halbert, M. Hoddle, and E. Grafton-Cardwell

Matt Daugherty, UC Riverside

mattd@ucr.edu

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The psyllid (pronounced: síl - lid) is a small insect, about the size of an aphid

Adult

Egg

5

Nymphal instars

It has an egg stage,

5 wingless juvenile stages called nymphs,

and winged adultsSlide3

Adult psyllids feed on young or mature leaves.

This allows adults to persist year-round

When feeding, the adult leans forward

and

tips its rear end at a characteristic 45o angle.Slide4

Y

ellow-orange eggs are tiny and tucked into the tips of new shoots, making them difficult to see

Female ACP strongly prefer to lay eggs on new leaves and shoots (“flush”)Slide5

Nymphs produce sugar-filled waxy tubules as they feed. The tubules are unique and easily seen

Nymphs can only survive

on

young, tender leaves and stems.

Thus, nymphs are found only when the plant is producing

new leaves.Slide6

As the psyllid feeds, it injects a salivary toxin that damages flush. If leaves survive, they twists as they grow

Twisted, notched

leaves

are an indicator the

psyllid has been there.Slide7

What plants does the psyllid attack?

All types of citrus and related plants in the family Rutaceae

Citrus (limes, lemons, oranges, grapefruit, mandarins…)Fortunella (kumquats) Citropsis (cherry orange)

Murraya paniculata (orange jessamine)Bergera koenigii (Indian curry leaf)Severinia buxifolia (Chinese box orange)Triphasia trifolia (limeberry)Clausena indica (wampei)Microcitrus papuana (desert-lime)Others…..

CalamondinSlide8

The psyllid feeds and reproduces on plants that we don’t think of as citrus, such as ornamentals

Plants that continuously produce new foliage, such as orange jessamine (

Murraya paniculata

) are preferred by the psyllid. Nursery shipments of this plant contributed to psyllid spread in FloridaSlide9

Why are we so worried about this psyllid?

ACP can transmit the

bacterium that causes

huanglongbing (HLB) Bacterium blocks nutrient transport, affecting tree growth, survival, and fruit production

Candidatus

Liberibacter asiaticusSlide10

Yellowing, poor quality fruit, tree decline, and death

Zinc

HLB

Earliest symptoms include blotchy, irregular yellowing of leaves

Fruit don’t develop properly: small, deformed, poor flavor

Lack of tree vigor, stunting; excessive fruit drop

Tree mortality in as little as 5 years

No cure!Slide11

The psyllid was first detected

in 1998, after which it spread rapidly throughout the state

assisted by shipment

of infested ornamentalsWithin 3 years the diseasespread to all citrus growing regionscitrus production is ~1/2 of what it was

production costs 50% higher

Human-assisted spread of the psyllid and disease in Florida

ACP & HLB in FloridaSlide12

Where are ACP and HLB in California?

ACP

was found in

San

Diego in 2008now present throughout Southern California (residential and commercial citrus) parts of the Central Valley parts of the Bay AreaMore than 20 cases of HLB have been found in Los Angeles CountySlide13

What is being done to manage ACP and limit HLB in California?

1

. Statewide monitoring for ACP and HLB residential and commercial trapping

inspections of nurseries 2. Quarantine zones established around infested areasregulations

on nursery shipments 3. Treatments of residential citrus 4. Biological control 5. Area-wide treatments of commercial citrus Slide14

How can nurseries help prevent spread of the pest and disease?

1. Help maintain the psyllid quarantine

educate customers

2. Minimize infestations on nursery plantsadopt a set of best management practicesQuarantines exist for the psyllid (blue lines) and the disease (red line) to limit spread Slide15

The

psyllid quarantine

and plant tagging system

Quarantines: 1. Prohibit plant movement to areas

outside the quarantine 2. Requires insecticide treatment of plants prior to shipping to retail. Retreatment after 90 daysThe color of a plant’s tag reflects its origin: Blue: plant came from production

nursery outside of quarantine Yellow: came from within the quarantine zoneSlide16

Inform customers about the pest and disease

1. Where they are relative to the quarantine zone

signage

near citrus trees

explain tagging system2. Psyllid & disease identificationsignage near trees provide brochures (quick tips)3. Control options for psyllid (insecticides, soaps, oil)

shelf talkershttp://www.cdfa.ca.gov/plant/pe/interiorexclusion/acp_quarantine.htmlUC IPM “Quick Tips”Slide17

Monitor nursery plants regularly for pest and disease

Check plants for evidence of the psyllid (especially flush)

Check leaves for blotchy yellow disease symptoms

Isolate any infested or suspected diseased plants

Report any psyllid finds or suspected symptomsSlide18

Prior systemic insecticide treatments are effective for upwards of three months

Trees can resideat retail sites

much longer 35% > 1 yrLong residencies

increase risk ofACP infestation

Ensure turnover of host plant stockSlide19

Ensure turnover of host plant stock

Prior systemic insecticide treatments are effective for upwards of three months

Encourage sale of ACP host plants before they become unprotected

1. Initiate a labeling program to keep track of when plants arrived date or different colors

2. Distribute trees in a way that encourages the sale of “older” plants firstSlide20

Adequate water is important for uptake of systemic insecticides. But, overwatering is problematic

contributes to pesticide runoff

limits retention of systemic insecticides in plantsUse water volumes that limit excess runoff

increase watering frequency and reduce amount

Use appropriate watering practicesSlide21

1. Screening

barrier to ACP establishment

the most effective, sustainable control measure2. Place in shaded area

ACP appears to prefer warm, sunny areas3. Move plants insidetemporarily house flushing plants in interior of store

Minimize psyllid access to host plantsSlide22

Limit temporal overlap in nursery stock

If possible, encourage brief absence of citrus and other ACP host stock

Absence of suitable host plants, even briefly, may limit ACP populations

no “reservoir” for insectslimits spillover infestation onto new plantsEncourage absence during

season when citrus stock is normally low anyway Slide23

Conventional insecticides

Mandatory treatments for nursery stock in quarantine protect plants for upwards of 90 days

with appropriate watering may extend the effectiveness of

systemic insecticidesRetreatment may be necessary to protect plants for longer durationstreatments can be made using labeled foliar and systemic insecticides

if possible, consider retreatment by licensed applicator, which are likely to provide a longer duration of effectivenessSlide24

Soaps can effectively kill ACP nymphs and adults by contact

little to no

residual period

not effective against eggsApply every 10 to 14 days when plants are flushinghelpful for other common pests (mites, whiteflies)

Insecticidal soapsSlide25

Horticultural oils decrease attractiveness of trees for psyllids

ACP avoid trees, reduce oviposition for up to a few weeks after application

With adequate coverage, can cause mortality of nymphs and eggs 0.5% - 1% adequate to

see beneficial effectsDon’t apply more than every 6-8 weeks, depending on climate

Horticultural oilsSlide26

Although pruning or hand removal of new shoots may temporarily decrease attractiveness to ACP, citrus responds by producing more flush

labor-intensive pruning

“treadmill” May have a longer-term negative effect on plant

Avoid removing new flushSlide27

Moderately high-pressure hosing to remove psyllid adults and nymphs (“bug blaster”)

may not effectively dislodge

psyllid eggsmore effective if used in conjunction with soaps or oils

Can contribute to overwatering or plant damage if done too often or too vigorously

Spray wash psyllids off plantsSlide28

Inform customers about pest, disease, quarantine, control options

Inspect plants, isolate infested plants, and report

Ensure prior insecticide treatments are effective

-encourage turnover of stock, don’t overwater Adopt supplementary control measures -screening, insecticidal soaps, pray washingCollectively these steps will minimize the potential for human-assisted spread of the psyllid and disease in California

Summary of Action StepsSlide29

http://

www.ipm.ucdavis.edu/QT/asiancitruscard.html

Downloadable brochureGeneral information on psyllid and disease biology, identification, and control

Share with customersSlide30

Online ACP & HLB training course for retail nurseries

http://class.ucanr.edu/

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ACP Distribution and Management

http

://ucanr.edu/sites/ACP

/