Introduction to Insecticides

Kinds, Modes of Action

Advantages of Insecticides

Fast (compared to biocontrol)

Generally reliable

Flexible

increase yield (PROFIT $$)

Potential Disadvantages of Insecticides

Direct hazards to humans

Perceived hazards, societal fears, litigation

Pest resistance

Adverse side effects on non-target organisms

Pest resurgences; secondary pest outbreaks

Insecticide Toxicity

(Direct Hazards to Humans)

LD50 = Amount of pesticide required to kill 50% of the test animals under standard conditions

• Expressed as mg pesticide per kg of body weight

• Useful for comparing toxicity of different pesticides

Remember: The lower the LD50, the more toxic the

pesticide!!

Insecticide Toxicity

- Oral

- Dermal

- Inhalation

Highly Toxic

Signal Words on Pesticide Labels

Moderately Toxic

Slightly Toxic or Relatively

Non-toxic

Human LD 50

Highly Toxic

Oral: 50 mg/kg or less; lethal dose of a few drops to teaspoon

Dermal: 200 mg/kg or less

Human LD 50

Moderately Toxic

Oral: 50-500 mg/kg; lethal dose of a teaspoon to a tablespoon

Dermal: 200-2,000 mg/kg

Slightly Toxic or

Relatively Non-toxic

Human LD 50

Slightly toxic

Oral: 500-5,000 mg/kg; lethal dose of an ounce to a pint

Dermal: 2,000-20,000 mg/kg

Low toxicity

(all compounds will have at least a caution)

Oral: > 5,000 mg/kg

Dermal: > 20,000 mg/kg

Toxicity versus Hazard

(Putting things into perspective)

“What is it that is not poison? All things are poison and nothing is without poison. It is the dose only that makes a thing not a poison.”

– Paracelsus, 1567

SubstanceLD50 for lab rat

(mg/kg)

LD50 for 150

pound Human

(ounces)

Sucrose (table sugar) 29,700 15.12

saccahrin 14,200 7.23

Benlate (fungicide) 9,500 4.84

Vinegar 3,310 1.69

Sodium chloride (table salt) 3,000 1.53

Resmethrin (insecticide) 2,500 1.27

Malathion (insecticide) 1,375 0.70

Aspirin 1,000 0.51

Sevin (insecticide) 500 0.25

Diazinon (insecticide) 300 0.15

Caffeine 192 0.10

Gasoline 150 0.08

Nicotine 53 0.03

Approximate lethal doses for naturally

occurring toxins

• The amount of caffeine in 100 cups of strong

coffee

• The amount of solanine in 100 - 400 pounds

of potatoes

• The amount of oxalic acid in 10 - 12 pounds

of spinach or rhubarb

• The amount of aspirin in 100 aspirin tablets

• The amount of hydrogen cyanide in 4

pounds of lima beans

Modes of action

Chlorinated hydrocarbons

Organophosphates

Carbamates

Pyrethroids

Insect Growth Regulators (IGR’s)*

Microbial insecticides*

Horticultural Mineral Oils

Inorganics (sulfur)

(generalized pesticide groups)

Neonicotinoids

* Multiple MOA’s exist in these and other groups

Understanding the different pesticide classes and how they work is important

Proper application

Determining if an application was successful

Choosing products that are most likely to control a pest without disrupting natural enemies…when feasible

Chlorinated Hydrocarbons

Examples: DDT, Chlordane, Dieldrin

Post-WWII “Green Revolution”

DDT revolutionized pest control in the 1940’s

Saved millions from insect-borne diseases such as malaria, typhus, during WWII

• Less acutely toxic than compounds used before 1940s (e.g. lead arsenate)

• Cheap

• Broad spectrum; i.e. effective vs. a wide range of different pests, BUT….

• Highly persistent, residues detectable in soil for >10 years

Chlorinated Hydrocarbons

Drawbacks of Chlorinated Hydrocarbons

• Stored in fatty tissues of vertebrates, excreted in milk (DDT)

• Biomagnification; adverse environmental effects

• Potential Carcinogenic Effects

• Pest resistance

Organophosphates

• Developed in Germany during WWII; spin-off of military nerve gas research

• Act as synaptic poisons, disrupting normal transmission of nervous impulses across synapses

• Contact poisons

Muscle

Seta

Motor NeuronSensory

Neuron

Synapse

A Simple Nerve Pathway

Muscle

Seta

Acetylcholine is released

to transmit impulse across

the synapse

Direction

of impulse

Muscle

Seta

Impulse crosses over. Then, an enzyme

called Cholinesterase clears the

acetylcholine from the synapse

Direction

of impulse

How Organophophates Kill

• The insecticide binds to the enzyme cholinesterase, deactivating it

• Without cholinesterase, the acetylcholine (transmitter substance) cannot be cleared from nerve synapses, so that the nerves keep “firing”

• Insect loses control of nervous system, with tremors, paralysis, death

Muscle

Seta

Direction

of impulse

With cholinesterase deactivated,

acetylcholine cannot be cleared

so the nerves keep “firing”

Carbamates• Same mode of action as organophosphates (i.e.,

synaptic poisons)

• Toxicity to vertebrates varies

• Highly toxic to all hymenoptera (parasitic wasps, bees, etc..)

• Contact poisons

Traditional Insecticides(Organophosphates & Carbamates)

• Broadly toxic

• Affect systems common to both insects and vertebrates; e.g. nervous system

• Risk to non-target organisms

• Secondary pest outbreaks

• Pest resurgences and resistance

Organophosphate and Carbamate insecticides used in Citrus

Phosmet – Imidan

Dimethoate – Dimethoate

Chlorpyrifos – Lorsban

Malathion – Fyfanon

Acephate – Orthene

Methidathion - Supracide

Aldicarb – Temik

Carbaryl – Sevin

Oxamyl - Vydate

Organophosphates Carbamates

Food Quality Protection Act

(EPA, 1996)

EPA: Reduced-Risk Pesticides

Reduced risk to human health

Reduced risk to non-target organisms including fish, birds and natural enemies

Reduce ground and surface water pollution

Low use rate, low pesticide resistance potential

Pyrethroids

• High toxicity to insects, but low toxicity to mammals

• fast-acting

• moderately rapid degradation in the environment

• used at very low rates

Pyrethroids

• Target-selective for insect nerves (= low vertebrate toxicity)

• Cause rapid paralysis of insect nervous system by changing solubility of nerve cell membrane (disrupting closure of the “sodium gates”)

• Axon poisons

K+ ions

Na+ ions

Electrical nerve impulseAxon nerve cell

Pyrethroids prevent ion channel closure; continued electrical impulse (rapid muscular paralysis)

Pyrethroid insecticides

Products labeled for use in FL citrus

• Fenpropathrin – Danitol

• Zeta-cypermethrin - Mustang

• Bifenthrin – Capture / Brigade

Despite their low mammalian toxicity, many pyrethroid insecticides are classified as “Restricted Use”because of their high toxicity to fish

Neonicotinoids

(Chloronicotinyls)

• “Agonist*” which binds directly with the

nicotinergic receptors in insects (like naturally

occurring acetylcholine), causing a nerve

impulse to be sent

• Not degraded rapidly by acetylcholinesterase,

so the nerve system keeps “firing”

– *def: “One that is engaged in a struggle”

Imidacloprid blocking acetyl choline receptor

Acetyl cholinesterase

Acetyl choline released into synapse

Chloronicotinyls block post-synaptic receptor sites for acetylcholine

Neonicotinoids

ARE NOT CHOLINESTERASE

INHIBITORS

Blocks post-synaptic receptor sites for acetylcholine

Neonicotinoids

(Chloronicotinyls)

Examples: Assail (acetamiprid), Admire

and Provado (imidacloprid),

Platinum and Actara

(thiamethoxam), Belay

(clothianidin)

Imidacloprid Toxicity & Mode of

Action

• Imidacloprid was “designed” to take advantage of

the differences in the binding properties of the

nerve synapses of mammals and insects

• Although mammals have the same general group

of receptors (nAChR), there has shown to be a

1000x lower binding affinity for vertebrates than

for insect receptors

Mode of Action of imidacloprid

• Excellent systemic performance• Soil treatment can be the most

consistent method of delivery• Moves with the transpiration

stream• Moves across the leaf

(translaminar)

Both contact and ingestion routes, ingestion is best

Insect Growth Regulators (IGR’S)

• Very target specific in mode of action

• Exploit an insect’s developmental biology

• “Reduced risk” insecticides

Chitin synthesis inhibitors

Juvenile hormone mimics

Insect Growth Regulators (IGR’S)

Buprofezin – Applaud

Diflubenzuron – Micromite

Chitin synthesis inhibitors

Chitin synthesis inhibitorsAffect the ability of insects to produce new exoskeletons when molting

• Typically slow acting

Epicuticle

Epidermis

Exocuticle

Endocuticle

Juvenile Hormone Mimics

Insect Growth Regulators (IGR’S)

Fenoxycarb – Award fire ant bait

Methoprene – Extinguish ant bait

Pyriproxyfen - Knack

Insect Growth Regulators (IGR’S)

Additional larval stage

Insect Growth Regulators (IGR’S)

High levels of JH at the wrong time produce an additional larval stage (much larger) than then dies because it can’t molt to the adult stage

Microbial Insecticides

- Commercial products containing pathogens or microbially-derived toxins that kill insects

- mainly bacteria, nematodes, fungi, some viruses

Bacillus thuringiensis (Bt)

• Used since 1950’s to control leaf-eating caterpillars (Bt kurstaki strain)

• Produced commercially by fermentation

• Very low vertebrate toxicity

• Short-residual

• Works better against small larvae than vs. larger ones

• Must be ingested to kill

Bt crystal/spore complex releases toxins when they contact the high pH midgut of insects

Bt products registered for use in Citrus

Agree – B.t. aizawai strain GC-91

Biobit HP – B.t. kurstaki strain ABTS-351

Condor – B.t. kurstaki strain EG2348

Crymax - B.t. kurstaki strain EG7841

Deliver - B.t. kurstaki

Dipel DF - B.t. kurstaki strain HO-1

Javelin WG - B.t. kurstaki

Lepinox WDG - B.t. kurstaki strain EG7826

Xentari DF – B.t. aizawai strain ABTS-1857

(all uses are for lepidopteran pests)

New strains of Bt are being developed that are active against insects other than Lepidoptera (e.g., mosquitoes, fungus gnats, Diaprepes root weevils)

Bt for controlling mosquito larvae in ponds

Bt for fungus gnat control in greenhouses

Other microbially based insecticides

These are not traditionally what we think of as microbial pesticides, but they are toxins derived from microbes.

Avermectin – Agri-mek

Spinosad – Spintor, Entrust, GF- 120 fruit fly bait

Abamectin – Agri-mek

Antibiotic derived from Streptomyces avermitilis

Inhibits nerve transmission in to the insect muscle

Requires several days to kill

Used in citrus for mites and leafminers

Spinosads

Derived from the bacterium Saccharopolyspora spinosa

Labeled for lepidopteran larvae, thrips and fruit fly baits

Kills by primarily by ingestion, excitation of the insect nervous system

Horticultural Spray Oils

- Highly refined petroleum-based oils

- Clog pest’s spiracles and suffocate

- Useful vs. small or sedentary pests, e.g., aphids, scale insects, mites

Horticultural Oils

Advantages:

- non-toxic to vertebrates

- no resistance potential

Disadvantages:

- must contact insect with spray

- potential for phytotoxicity

Pesticide Resistance Management

Pesticide Resistance

Management

• Use pesticides at labelled rates

• Rotate between pesticides with different modes

of action

• Use products less likely to harm natural enemy

populations

• Calibrate equipment for accurate application:

use recommended spray volumes and pressures

Insecticide Resistance Action Committee (IRAC)www.irac-online.org

Fungicide Resistance Action Committee (FRAC)www.frac.info

Herbicide Resistance Action Committee (HRAC)www.hracglobal.com

Management of Asian citrus

psyllid and Citrus Greening Disease

Management of Citrus Greening Disease

“The World’s Experience”

Greening management must include: 1) propagation of clean nursery stock, 2) removal of infected trees in the field and 3) “effective” psyllid control

Difficulties Managing HLB

• Symptoms difficult to diagnose

• Resemble nutrient deficiencies

• Must use PCR for confirmation

• Latency period in plant of 1-2 + years

from infection to first observation of

symptoms

Asian Citrus Psyllid as a vector of greening disease

The damage caused to new growth on young trees by psyllid feeding is of minor concern ...

…Use of insecticides to manage psyllid populations is necessary to slow (not eliminate) the spread of greening disease in a grove once present.

Insecticide Use for Psyllid

Control

• Brazil: varying success using 6 to 26

applications per season (Belasque et al.

2008)

• Asia: worst-case situations up to 52

applications per year (Beattie and Holford

2008)

• Florida: much variation; on average 8 to 12

applications per year

Psyllid Control in Florida

What hasn’t worked…

– use of selective insecticides

targeting immature psyllids (IGR’s, etc…)

– diflubenzuron, fenpyroximate, petroleum oil,

abamectin, etc…

– targeting psyllid populations on new flush

– lengthy periods of new citrus flush allowed

psyllid populations to continue to increase when

adults were not controlled

Psyllid Control in Florida

• What does work

– Applications of broad-spectrum insecticide

made to target adults prior to new flush

– Florida citrus growers now averaging 6-8+

broad-spectrum insecticide applications per

season for psyllid control

– fenpropathrin, imidacloprid, chlorpyrifos,

carbaryl, dimethoate, phosmet, etc…

– estimated costs for psyllid control $300 / A

Psyllid / HLB Management

Repeated use of insecticides is not a

long-term solution for Florida

growers

• High cost of applications

• Disruption of established biocontrol

agents of other potentially important

pests

• Pesticide resistance likely

Current Problems Managing

Asian citrus psyllid

• Easy to kill…Hard to control !!!

Primary reasons for repeated

applications?

• Short residual of pesticide control

– Foliar applied insecticides

• Psyllid movement behavior

ACP Caging Study

> 60%

survival

following

exposure

12 DAT

Psyllid Movement

Protein marker 1 Protein marker 2

ACP movement between adjacent groves (3 days)

Boina et al. 2009. Environ. Entomol. 38: 1250-1258

~ 100m

Psyllid Movement

Protein marker 1 Protein marker 2

ACP movement between adjacent groves (3 days)

Boina et al. 2009. Environ. Entomol. 38: 1250-1258

~ 100m

12%

88%

20%

80%

Reasons for failed control?

• Collectively, these results explain how

the lack of residual control combined

with psyllid movement can result in the

need for frequent repeated insecticide

applications.

Citrus IPM – Where’s it headed ?

• Biological Control

• Pest Population Monitoring

• Cultural Practices

• Judicious Use of Pesticides

Traditional IPM Practices:

Biological Control

There are numerous natural enemies of psyllids present that suppress psyllid populations, especially in the summer and fall

Use of broad spectrum foliar insecticides will present a problem in maintaining populations of the natural enemies of psyllids and other potential pest species

Insect-vectored pathogen…

in a perennial crop

Insect-vectored pathogen…

in a perennial crop

Biological control has never been successful in controlling an insect vector of plant disease…especially in a perennial crop!

low/no threshold for pest (vector) presence crop continually exposed to threat over

multiple years cant plow under the crop and start over next

year

Biological Control Prospects?• Broad-spectrum insecticide use cant last

forever…we hope

– Novel solutions to reduce reliance on pesticides

• Resistant trees?

• Organic Groves

– If they survive…biocontrol will be important to help

maintain populations at reduced levels than left

uncontrolled

• Urban / Dooryard Environments

– Little acceptance of pesticide use

– Biocontrol may help reduce threats to commercial

citrus coming from these areas

Psyllid Monitoring

Feasibility of pesticide applications based on psyllid scouting?

• Psyllid populations can explode seemingly overnight

• High number of offspring

• Short generation time

• neighboring grove effects (psyllid movement)

• Lack of effective action thresholds

• (spray-based monitoring)

Psyllid Monitoring

• Where psyllid and HLB are established,

psyllid monitoring has limited value

– Small citrus acreage…may be able to time

applications based on monitoring

– Large citrus acreage…difficult to detect and

respond in a timely manner

• Both calendar-based sprays and clean-

up sprays based on scouting will likely

be required

Cultural Practices

Ongoing research:

•Flush management – factor that promote / limit new leaf growth

• Altering host plant suitability –changing plant nutritional status

•Host plant resistance – identification of psyllid resistant cultivars and incorporate into breeding program

Use of Pesticides

Pesticide Application Methods

• Trade-offs in level of control provided

Aerial applications…poor inside

coverage of canopy

Low volume…no residual effects;

most product lost to drift

Airblast…slow and expensive;

allows psyllid recolonization

Dormant Sprays

• First use of dormant sprays in Florida

citrus…for citrus rust mites!!!“Where a preventive schedule has been followed,

control…has been more effective…than where a

corrective schedule has been followed…the period of

control was longer when targeting low

populations…than when treatment was delayed until a

medium to heavy pest infestation had developed”

– W. L. Thompson 1948, Entomologist, Lake Alfred

Dormant Sprays

• FL growers often make 2 dormant

sprays for psyllid

– 1st immediately after fall flush period

• Control adults that developed during fall flush

period

– 2nd just prior to early spring flush

• Ensure no adults present to reproduce on new

flush

• Dormant sprays important to

help keep psyllids low through

bloom

Foliar Insecticides for Psyllid

Control in Florida – use of broad-spectrum insecticides targeting

adult psyllids

• fenpropathrin, imidacloprid, chlorpyrifos, carbaryl,

dimethoate, etc…

– start with winter dormant sprays to minimize

psyllid population growth on spring flush

– Additional broad-spectrum sprays prior to new

flush throughout the year

– Most growers in FL have best success using

monthly sprays

Importance of Young Tree

Protection

Young tree care

• Young trees crucial to ensuring future

citrus production

– Perhaps more important than control of

psyllids on mature trees…at least in FL now

• Rely primarily on soil-applied systemic

neonicotinoid insecticides

– imidacloprid, thiamethoxam and clothianidin

Application of systemic

neonicotinoids

Soil-applied

neonicotinoids

• Provide protection from both psyllids

and leafminer

• Provide 6+ weeks of protection

• Must be applied 2 weeks prior to flush

• Can be applied to trees up to 9’ in

height…but you have to increase

product rate with increasing tree size

Soil-applied systemic

insecticides

Yearly Rate Limits

–Admire Pro (imidacloprid)

• 14 fl oz / A (0.5 lb a.i.)

–Platinum 75 SG (thiamethoxam)

• 3.67 oz / A (0.172 lb a.i.)

–Belay 50 WDG (clothianidin)

• 12.8 fl oz / A (0.4 lb a.i.)

Rate per acre (single application)(based on 140 trees / A)

New Reset

(2-3’ height)

1-2 yrs

(3-5’ height)

3-5+ yrs

(5-9’ height)

Admire Pro 4.6F 3.5 fl oz (4 apps) 7 fl oz (2 apps) 14 fl oz (1 app)

Platinum 75 SG 1.835 oz (2 apps) 1.835 oz (2 apps) 3.67 oz (1 app)

Belay 50 WDG 3.2 fl oz (4 apps) 3.2 fl oz (4 apps) 6.4 fl oz (2 apps)*

Rate per treeNew Reset

(2-3’ height)

1-2 yrs

(3-5’ height)

3-5+ yrs

(5-9’ height)

Admire Pro 4.6F 0.025 fl oz 0.05 fl oz 0.1 fl oz

Platinum 75 SG 0.0131 oz 0.0131 oz 0.0262 oz

Belay 50 WDG 0.0229 fl oz 0.0229 fl oz 0.0457 fl oz

* Currently Belay can only be applied to nonbearing trees

Tree size Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Reset

(<3’)P A A B B A A P

1-2 yr

(3-5’)P A B B B B A P

3-5 yr

(5-9’)

bearing

P A A

A= Admire (imidacloprid); B=Belay (clothianidin); P=Platinum (thiamethoxam); Products are positioned

for use at certain times of the year based on water solubility and likelihood for significant rain events.

Season-long ACP control(foliar applications to prevent pesticide

resistance to neonics shown in orange)

Value of Insecticide

Applications

Population suppression vs.

prevention of pathogen transmission

Can we protect trees from

becoming HLB-infected?

Kill psyllids before they infect a tree with the HLB bacteria

Candidatus Liberibacter asiaticus

• Causal agent of HLB

• Gram-negative bacteria

• Phloem-limited bacterium

How insecticides affect transmission

• Factors influencing feeding behaviors–Plant surface exploration

– Labial dabbing

–Test probing

–Probing of extended duration

• Chemical stimuli affect these steps influencing transmission

• Transmission can be disrupted as a result of lethal or sublethal effects of insecticides

Feeding Behavior Assessment

• Electrical Penetration Graph

Feeding ? Or not Feeding ?

Psyllid behaviors

• Probing behaviors–Stylet penetration into plant

–Phloem penetration

–Phloem salivation

–Phloem ingestion

–Xylem ingestion

• Non-probing behaviors–Walking

–Standing still/jumping off plant

Waveform correlations

Top

Bottom

Top

Bottom

Pathway or stylet penetration – C

Phloem penetration – D

Phloem salivation - E1

Phloem ingestion - E2

Bonani et al 2010

Waveform correlationsTop

Bottom

Xylem ingestion - G

Bonani et al 2010

Non probing/non walking - z

Non probing/walking - np

EPG Assessment of psyllid feeding

EPG Analysis of ACP Feeding Behavior

• Can insecticides prevent pathogen

transmission from occurring?

(untreated)

Results of EPG Studies to Date

Product evaluatedActive

ingredientApplication method

Duration of psyllid

feeding disruption

Admire Pro 4.6F imidacloprid Soil drench At least 6 weeks*

Platinum 75 SG thiamethoxam Soil drench At least 6 weeks*

Belay 50 WDG clothianidin Soil drench At least 6 weeks*

Provado 1.6 F imidacloprid Foliar applied 3 weeks

Danitol 2.4 EC fenpropathrin Foliar applied 2-3 weeks

Lorsban Advanced chlorpyrifos Foliar applied 24 hours

Delegate WG spinetoram Foliar applied 24 hours

Movento MPC spirotetramat Foliar applied none

*no evaluations of the soil-applied neonicotinoids have been made beyond 6 weeks.

The primary benefit of foliar insecticide

use is ACP population suppression

Tree size Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Reset

(<3’)P A A B B A A P

1-2 yr

(3-5’)P A B B B B A P

3-5 yr

(5-9’)

bearing

P A A

A= Admire (imidacloprid); B=Belay (clothianidin); P=Platinum (thiamethoxam); Products are positioned

for use at certain times of the year based on water solubility and likelihood for significant rain events.

ACP control on young trees(foliar applications to prevent pesticide resistance to

neonics shown in orange)

Value of Insecticide

Applications

• Soil-applied neonicotinoids can reduce

the likelihood of young trees from

becoming HLB infected

– Reduction in psyllid populations

– Minimize chances for pathogen transmission

through reduction in phloem feeding behaviors

Value of Insecticide

Applications

• Foliar-applied insecticides provide

population suppression but are not likely

to provide much benefit in terms of

preventing pathogen transmission (via

disruption of psyllid feeding)

– Rotation of foliar products will be important to

help prevent resistance to neonicotinoids used

extensively in young tree plantings

Tree size Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Reset

(<3’)P A A B B A A P

1-2 yr

(3-5’)P A B B B B A P

3-5 yr

(5-9’)

bearing

P A A

A= Admire (imidacloprid); B=Belay (clothianidin); P=Platinum (thiamethoxam); Products are positioned

for use at certain times of the year based on water solubility and likelihood for significant rain events.

Season-long ACP control(foliar applications to prevent pesticide

resistance to neonics shown in orange)

Improving Protection of

Mature Trees?

Since foliar insecticides are not likely to prevent mature trees from becoming HLB infected…

…How can we improve psyllid control on mature trees?

Area-wide ACP control programs

– Coordinated effort

– Simultaneous treatment of groves in a “large”area

– Delay psyllid recolonization of groves

• Goals:

– Greater reduction in overall psyllid

populations

– Reduce the need for frequent reapplication of

pesticides

Basis of Area-wide Control

(Knipling 1979) Basic Principle of Total Population Control:

“Uniform suppressive pressure applied against the total population of the pest over a period of generations will achieve greater suppression than a higher level of control on most, but not all, of the population each generation”

Key FeaturesGrove-by-Grove Approach Area-Wide Approach

• Targeting portion of population

• Targeting entire population

• Refugia left for immigrants(reapplication of insecticides)

• No refugia for immigrants(reduction in insecticide use)

• Pests with limited mobility • High pest mobility

• Low value crop with mediumto high pest tolerance

• High value crop with low pest tolerance

• Reactive approach to pestpresence

• Proactive approach to pestpresence

• Complicates pesticideresistance management

• Facilitates pesticide resistance

management

(Summarized from: Hendrichs et al. 2007)

Area-wide Control• Recommendation of National

Academies of Science

– Development of “Citrus Health

Management Areas” (CHMAs)• Facilitate the coordination of psyllid control

and other HLB management practices

– Best chance for surviving HLB

until more long-term sustainable

solutions developed

• Thus far Florida has only adopted

coordinated psyllid control efforts

www.flchma.org

• 38 CHMAs

statewide

• 486,079 acres

(commercial

citrus)

CHMA approach to

psyllid management

• Coordinate timing of pesticide

applications

– Reduce overall psyllid populations

– Cut down on cost and number of

pesticide applications needed to

stay productive

• Coordinate mode of actions used

– Managing pesticide resistance by

minimizing repeated exposure to same

MOA

Results to Date

• Psyllid populations are decreasing

where coordinated applications

have been implemented.

Central Highlands 17/27 CHMA

• Total blocks = 423

– 7,919 grove acres

– Blocks sampled = 87

– 20.5% of CHMA scouted

– In 62% (54/87) of the blocks sampled, no psyllids were found

CHMA website(www.flchma.org)

• Facilitate communication between

growers

• Reference point for information of

upcoming CHMA events

• Tool to convince non-participants to

join the effort

– Demonstration of benefit (psyllid scouting

reports)

– Educate growers (absentee growers)

Developing a comprehensive

pest management program

• Psyllids/HLB are the primary focus of

current pest management programs

• There are still other pests requiring

management– Rust mites

– Leafminer

– Weevils

– Other site specific pests

Developing a Management Strategy

Multi-targeting of pests

• use of one pesticide application to control several

pests simultaneously

• planning ahead to reduce insecticide inputs

http://edis.ifas.ufl.edu/pdffiles/IN/IN80700.pdf