Introduction to Insecticides - Citrus Research and …€¢Broad-spectrum insecticide use cant last...
Transcript of Introduction to Insecticides - Citrus Research and …€¢Broad-spectrum insecticide use cant last...
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