PMA 5205

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PMA 5205 Psyllids and Leafminer Changing the
management of arthropod pests of Florida citrus
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Citrus Canker Citrus Greening
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Pupal stage 6-22 days
Citrus Leafminer Lifecycle
Egg 2-10 days
4 larval instars 5-22 days
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CLM can also cause damage to green twigs and in
rare cases cause mining on fruit surface
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Seasonality of CLM in Florida

• overwinter as adults with no reproductive
  diapause
• very low populations exist throughout winter
  months on the low levels of new flush being
  produced
• with warmer weather, CLM produce more offspring
  more rapidly
• populations build up to noticeable levels when
  the summer flush occurs (usually May to June)

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Importance of CLM Damage

• Damage alone not significant on mature trees
  (New flush Canopy)
• Damage on non-bearing trees can reduce tree
  growth
• increased time to bring trees into production

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Canker / CLM Relationship
Canker incidence can be up to 50 higher in
groves where CLM damage is abundant (Sohi and
Sandhu, 1968)
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Choice Timing of Pesticide Applications
Non-bearing citrus

• soil-applied imidacloprid application is the
  best option for preventing CLM damage
• applications should be made 10-14 days prior to
  anticipated flush
• expect about 8 weeks of control

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Choice Timing of Pesticide Applications
Non-bearing citrus

• soil-applied imidacloprid just prior to summer
  flush and again just prior to the fall flush
  will provide control of CLM during this peak
  time for CLM damage
• will also provide control of Asian citrus
  psyllid during these times as well.

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Choice Timing of Pesticide Applications
Bearing citrus

• preventing damage on bearing trees for canker
  management much more difficult
• must rely on foliar applications if control
  warranted
• there are no soil-applied systemic insecticides
  available for CLM control on large, bearing trees

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Choice Timing of Pesticide Applications
Bearing citrus

• as a general rule, there have never been any
  soil- applied systemic organophosphate or
  carbamate insecticides shown to provide
  effective control of CLM damage
• this includes aldicarb (Temik), dimethoate,
  oxamyl (Vydate), metasystox (MSR)

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Control of Damage by Citrus Leafminer
Soil imidacloprid application Sept. 4 Foliar
applications Sept. 18
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Control of Damage by Citrus Leafminer
Treatments applied May 19
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Timing of application for leafminer control
FOLIAR APPLICATIONS
13 days from general budbreak is earliest time
for application
Last potential date for leafminer application is
31 days after budbreak
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Effects of Cultural Practices
Promoting winter flush may result in higher CLM
populations earlier in the season

• hedging and topping
• excessive irrigation
• fertilization regimes

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Biological Control of Citrus Leafminer
Ageniaspis citricola Imported into Florida from
Australia in 1994
Parasitism rates up to 86 observed late in the
season
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Use of Pheromones in Leafminer Management
In 2006, the full pheromone of the citrus
leafminer was identified by researchers in
California.
Moreira, J.A., McElfresh, J.S. and J.G. Millar.
2006. Identification, synthesis, and field
testing of the sex pheromone of the citrus
leafminer, Phyllocnistis citrella . J. CHEM.
ECOL. 32 (1) 169-194.
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CLM find each other for mating with sex pheromones
Wind
Pheromone plume
Photo credit J. Jones, University of Arizona

• Females release pheromone
• from specialized gland

• Male has special
• receptors on antennae
• which smell the
• females pheromone

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Potential uses of leafminer pheromone in citrus
production

• Traps to monitor leafminer populations to time
  pesticide applications
• Use pheromones for mating disruption
• Projects currently underway

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Citrus Leafminer Trapping study
No lure
With lure
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Every revolutionary idea evokes three stages of
reaction 1. Its completely impossible 2.
Its possible but its not worth doing and 3. I
said it was a good idea all along!
Arthur C. Clarke

• Male moths follow pheromone
• trial to locate female

• Application of synthetic pheromone sources
• confuses males and prevents mating, reducing
• larval numbers and crop damage

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Asian Citrus Psyllid
Diaphorina citri Kuwayama
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Asian Citrus Psyllid Distribution (FL)

• First detected in dooryard citrus
  trees in south Florida in 1998
• subsequent finds in nursery plants (orange
  jasmine Murraya paniculata) in discount stores
  throughout the state
• psyllid well established in primary citrus
  growing areas of FL and cannot be eradicated

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After Asian citrus psyllid colonized SE Florida
(red), it moved on Murraya paniculata to other
counties very rapidly.
Rapid movement made eradication unfeasible Now
found in SE areas of Texas and Mexico.
Portions of TX and Mexico are infested with ACP
Map Katrina Vitkus
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Psyllid Discovery in Mexico
(March 2006)
(April 2002)
HLB thus far only detected in Florida
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Asian Citrus Psyllid

• 5 nymphal stages

• 10 generations / year

• Life cycle takes 15-47 days

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Adult Asian citrus psyllids

• 3-4 mm in length
• mottled wings
• wings held roof-like over body

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Asian Citrus Psyllid Adults

• Adult psyllids can feed on both new and mature
  leaf flushes prefer young leaves
• When young leaves not available, adult psyllids
  are found on underside of mature leaves feeding
  on leaf midvein
• Mean longevity of females increases with
  decreasing temperature within 59-86F (
  15-30C)

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• Adults gather at newly emerging growing tips and
  on young flushes, feed and mate

Females ready to lay eggs have orange coloration
of their abdomens
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Asian Citrus Psyllid Eggs

• Adults oviposit ONLY on young leaf flush
• Eggs are about 0.3 mm long and almond shaped
• Eggs are pale when deposited, turn yellow then
  orange as they mature. Often difficult to see
  without hand lens

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Asian Citrus Psyllid Nymphs

• 0.3 mm long in the first instar
• 1.6 mm long as fifth instars.
• Nymphs are yellow in color with red eyes and
  visible wing pads in larger nymphs

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Asian Citrus Psyllid Nymphs

• early nymphal stages easily mistaken for aphids
  
• white waxy secretions provides an easy means of
  distinguishing from aphids at a distance.

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Psyllid population growth

• Need young tender flush to reproduce

• Temperatures in the range of 68-86F are ideal
  for rapid buildup of psyllid populations

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Psyllid damage
In the absence of the greening pathogen, psyllid
control has targeted young trees to protect new
growth from damage that results in reduced tree
growth.
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New leaf distortion (high psyllid populations)
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Witches broom effect
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Dieback of new growth
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Psyllid nymphs produce waxy secretions similar to
aphid or scale insect honeydew
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Sooty mold - growing on sticky residues from
secretions from psyllid nymphs
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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 now with the
presence of greening in Florida.
Management of Asian citrus psyllid populations is
necessary to slow the spread of greening disease
in a grove once present.
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http//www.doacs.state.fl.us/pi/chrp/greening/cgma
ps.html
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Greening management programs in other countries

• Use of disease free budwood
• Isolation of screened nurseries
• Heavy insecticide use on young and non- bearing
  trees
• Apply insecticides to bearing trees when new
  flush present
• Remove visibly infected trees

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Greening management
(In China)
Farm 1 Infected trees were removed and every
flush throughout the year was sprayed with
insecticides for psyllid control. Result 14
trees infected within 4-5 years
Farm 2 from 1999-2005, no management practices
were implemented for psyllid control infected
trees were not removed and no insecticides were
applied for psyllid control. Result 100 of
trees infected in 6 years
(Results reported by J.M. Bove 2005 Citrus
Canker and Huanglongbing Research Workshop)
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Cambuhy Farm - Brazil
Slide courtesy of F. Tersi, Cambuhy Farm
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Application of Organophosphate insecticide
(Dimethoate) for Psyllid control
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Developing a Psyllid IPM Program

• Monitoring Psyllid Populations
• Effective Use of Chemical Controls
• Biological Control
• Cultural Practices

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Developing a Psyllid IPM Program
Monitoring Psyllid Populations
Knowing when psyllid populations are increasing
is important to help time pesticide applications
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Traps for monitoring Psyllid Populations

• Adult psyllids can be collected using yellow
  colored sticky cards

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Traps for monitoring Psyllid Populations
Problems with using sticky traps

• Psyllids are localized or patchy within a grove.
  
• Psyllids typically do not move much when new
  flush is abundant
• Trap numbers are typically low, its easier to
  find psyllids on flush than on the traps
• Would require many sticky cards per acre to
  adequately estimate psyllid abundance
• In South Africa, the use of sticky traps has not
  been adopted because too labor intensive

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CREC Psyllid Research Colony in Greenhouse
No psyllids (after 1 week)
1,000 psyllids
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Monitoring Psyllid Populations
Important to monitor when new flush is available
Critical time is January through June when
temperatures are cooler and flush is abundant
Check expanding terminals for aggregations of
psyllids
Adult psyllids found on underside of leaves near
leaf midvein when no new flush is available
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Monitoring Psyllid Populations

• Eggs tucked away in very young, newly forming
  leaves and leaf buds.

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Monitoring Psyllid Populations

• Inspect new leaf and shoot flushes of citrus and
  citrus relatives such as orange jasmine, Murraya
  paniculata. Look for white honeydew and leaf
  distortion on new leaf flush and shoots.

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Developing a Psyllid IPM Program
Effective Use of Chemical Controls

• based on pest pressure
• Protect the new flush, especially in spring and
  summer
• use of systemic products on young trees, have to
  rely on foliar sprays for mature trees
• use of the systemic product Temik on large trees
  may provide some suppression of psyllid
  populations

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Recommended Insecticides for Asian Citrus Psyllid
2007 Florida Citrus Pest Management Guide
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Soil-applied Insecticides for Psyllid Control
Young trees (lt 6-8 feet tall) - imidacloprid

• Soil applied systemic insecticides are most
  effective
• must be applied about 2 weeks prior to flush for
  best results
• in sandy soils, can be washed away if heavy
  rains occur with 12 -24 hr post treatment
• have fewer negative effects on natural enemy
  populations

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Maximum imidacloprid allowed per season (0.50
lb AI/Acre)

• Apply as drench directly to base of tree.
• Microjet injection throws most material
• outside of root zone

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Soil-applied Insecticides for Psyllid Control
Mature trees (gt 6-8 feet tall) aldicarb Temik

• Temik shown to be effective on both young and
  mature citrus for suppression of psyllid
  populations
• application 10 days prior to flush for small
  trees application 30 days prior to flush for
  large trees
• use 33 lbs / A rate

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Psyllid Control Trial on Mature Trees (2005)

• 5 acre block Hamlin on Carrizo at CREC
• tree height 10 feet tree skirt diameter 8-10
  feet
• trees hedged October 1, 2005
• Temik 33 lbs / A applied October 12, 2005
  (special research permit)
• plot size 6 x 2 12 trees / plot replicated 5
  times
• weekly evaluation of psyllid nymph, egg and
  adult populations
• trees continuously hand-pruned to promote flush
  and psyllid populations

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Control of Asian Citrus Psyllid Nymphs (2005)
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Control of Asian Citrus Psyllid Nymphs (2005)
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Temik Application for Psyllid Control

• Make application 30 days prior to anticipation
  of flush

• Use 33 lbs / A rate

• Use of lower rate will decrease effectiveness,
  time to control and duration of control

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Foliar-applied Insecticides for Psyllid Control

• Use on both young and mature trees
• applied as soon as new flush is beginning to
  expand
• typically broad-spectrum products
• most have negative effects on natural enemies

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Neonicotinoid trial 2006-2
Admire Pro soil application made 13 days prior
to other treatments to allow uptake
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Psyllid Foliar Trial 2006-4
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Psyllid Foliar Trial 2006-2
soil application made 13 days prior to other
treatments to allow uptake
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Petroleum oil sprays
Mean number of psyllid adults
4 DAT
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Petroleum oil sprays
Psyllid eggs
Control
Psyllid nymphs
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Use of petroleum oil sprays for psyllid control

• little or no control of adults
• residues possibly repel adult psyllids for a
  short period of time (several days)
• good control of nymphs that are present
• must have thorough coverage
• must reapply between 7-10 days after first
  treatment and continue to reapply until all new
  flush is fully expanded
• limitations of time and equipment

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See also Proc. Fla. State Hort. Soc. 118 49-53
(2005)
CHEMICAL CONTROL AND MANAGEMENT APPROACHES OF THE
ASIAN CITRUS PSYLLID, DIAPHORINA
CITRI KUWAYAMA (HOMOPTERA PSYLLIDAE) IN FLORIDA
CITRUS
http//fulltext.fcla.edu/DLData/SN/SN00971219/0118
/049_53.pdf
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Problems with Broad-Spectrum insecticide use seen
in Brazil
repeated use of certain pesticides will lead to
similar problems in Florida
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Ortézia scale
Orthezia praelonga
Significant pest now in Brazil
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Ortézia scale Sooty mold
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Ortézia scale
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Ortézia scale
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Black Parlatoria Scale Parlatoria ziziphus
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Citrus snow scale Unaspis citri
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Green scale Coccus viridus
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Developing a Psyllid IPM Program
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
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Natural Enemies of Juvenile D. citri in Florida
Spiders Hibana velox (Anyphaenidae)
Chiracanthium inclusum (Clubionidae) Hentzia
palmarum (Salticidae) Oxyopes sp. (Oxyopidae)
Ladybeetles (Coccinellidae) Curinus
coeruleus Cycloneda sanguinea Exochomus
childreni Harmonia axyridis Olla v-nigrum
Hemiptera (Anthocoridae) Orius sp.
Green Lacewings (Chrysopidae) Chrysoperla
rufilabris Ceraeochrysa spp. (2 - 3)
Ants (Formicidae) Dorymyrmex bureni Pseudodmyrmex
gracilis
Brown Lacewings (Hemerobiidae) Micromus posticus
Parasitoids Tamarixia radiata
Hoverflies (Syrphidae) Allograpta obliqua
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Biological Control Olla v-nigrum
J. P. Michaud
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Biological Control Harmonia axyridis
Multicolored Asian ladybeetle
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Classical Biological Control

• Tamarixia radiata
• External Parasite
• Originally from India
• Variable incidence in Florida.

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Tamarixia Radiata Adult and Egg
http//www.fftc.agnet.org/library/article/tn200100
5.html6
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T. radiata Larva and Prepupa
http//www.fftc.agnet.org/library/article/tn200100
5.html6
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Incidence of Parasitism by Tamarixia in SW Florida
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Cohort Studies to Evaluate Mortality

• Count eggs/1st instars on young flush
• Cage half of flush
• Daily counts until emergence

P. Stansly, R. Pluke and A. Urbaneja
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Cohort Study, Immokalee
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Developing a Psyllid IPM Program
Cultural Practices
Removal of surrounding host plants of Asian
Citrus Psyllid
Website listing all known host plants for psyllid
and greening pathogen
http//www.doacs.state.fl.us/pi/enpp/ento/greening
/hostlist.pdf
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Orange Jasmine, Mock Orange
(Murraya paniculata)

• a preferred host for ACP

• recent work suggests Murraya is a host for HLB

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Is orange jasmine (Murraya paniculata) a host for
the greening pathogen ?
Most likely!
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Orange Jasmine
(Murraya paniculata)

• Recent Findings
• Transmission of HLB from citrus to Murraya
  using Dodder
• Tranmission of HLB from citrus to Murraya via
  psyllids
• Work ongoing to demonstrate that psyllids can
  move HLB from Murraya to citrus

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Chinese box orange, Box thorn
(Severinia buxifolia)

• host for ACP

• can transmit greening disease to psyllids

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Limeberry
(Triphasia trifolia)

• occasional host for ACP

• can transmit greening disease to psyllids

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Some Important Questions!

• How long does it take for a feeding psyllid to
  transmit greening to a healthy plant?
• Will an infected psyllid feeding on a healthy
  plant treated with systemic or foliar
  insecticides die before transmitting the
  disease?
• Is there a true (economic) benefit to monthly
  insecticide applications like used in other
  countries compared to limiting sprays to the
  primary spring and summer flushes?
• How far can a psyllid fly?

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Transmission by Diaphorina citri

• Acquisition time 15-30 min (apparently in the
  phloem)
• Inoculation time lt1 h
• Latent period 8-12 days 21 days 24 h (??)
• Acquisition by nymphs (4º. e 5º. instars) and
  adults
• Inoculation only by adults (mobility)

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Transmission by Diaphorina citri

• Bacteria in body of the insect and salivary
  glandule
• Persistency in the vector 3 months (!!)
• No transmission by eggs
• Transmission efficiency 1 a 100 (??)
• Yellow attract adults (diseased plant)

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Current Recommendations
Non-bearing trees / Resets

• Soil-applied systemic insecticide applications
  during spring or summer flush (dependent on
  psyllid pops) repeated in fall
• Between soil applications, use foliar
  applications to manage psyllid populations when
  increasing on new flush
• Important not to overlook additional care of
  resets in mature blocks of trees

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Developing a Management Program
Once greening is present in a grove, do you reset
trees in place of removed HLB infected trees?

• Young trees flushing at different times than
  surrounding mature trees will attract psyllids
• Young trees will require extra care, especially
  in this situation

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Current Recommendations
Bearing Trees

• aldicarb (Temik) is the only soil-applied
  systemic that has any effect on psyllids on
  bearing trees (30 days prior to 1st flush)
• foliar applications targeting the spring and
  summer flush likely to provide most reduction
  in psyllid numbers
• supplemental foliar sprays used during summer
  when needed (or practical)

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Bearing Trees (Summer / Fall)
Additional Sprays

• if flush expected to be synchronized, use
  foliar sprays specifically to target psyllids
• if flushing is continuous (unsynchronized),
  multi-targeting of pests is probably more
  economically feasible

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Developing a Management Strategy
Multi-targeting of pests

• use of one pesticide application to control
  several pests simultaneously

• planning ahead to reduce insecticide inputs

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List of insecticides and miticides recommended
for use in the Florida Citrus Pest Management
Guide and their effects on different pests and
beneficial insects.
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Multi-targeting of pests
Examples
Spring (young trees) psyllids Admire appl. will
control psyllids, aphids and leafminers
Spring (large trees) psyllids, pink citrus rust
mites Temik will also control aphids and
suppress nematodes
Summer rust mites Agri-mek will control
leafminer with some psyllid suppression
Summer disease/mite control petroleum oil
applications will provide short term suppression
of psyllid nymph populations when new flush
present but not a stand alone method psyllid
control
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Developing a Management Program

• Is there a threshold for the number of psyllids
  present that justify treatment?
• takes only 1 psyllid carrying pathogen to
  infect a tree
• allowing any infected psyllids to go
  uncontrolled in one part of a grove will likely
  result in spread of the psyllid and pathogen to
  trees in other parts of the grove.

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Developing a Management Program

• Psyllid controls should be timed primarily to the
  spring and summer (May/June) flush
• psyllids overwinter as adults
• populations begin building on spring flush
• populations reach highest levels on summer
  flush
• easier to time applications to synchronized
  early season flushes

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Possible Management Plan
Non-Bearing citrus
Plan on two imidacloprid soil applications one
in the spring or early summer and one in the
fall. With proper equipment could use Temik in
spring and imidacloprid applications for the
early summer (May) and fall (August) flushes.
Additional flushes foliar applications of
Danitol, Micromite, Lorsban, (Dimethoate not
labeled for psyllid though?)
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Possible Management Plan
Bearing citrus
Spring flush (March) aldicarb (Temik) Danitol
appl.
Summer flush (May/June) imidacloprid foliar
application (Provado)
Additional Multi-targeting sprays Agri-mek
oil, Micromite, Lorsban, (Dimethoate not labeled
for psyllid though?), petroleum oil
Fall flush (August/Sept) imidacloprid foliar
application (Provado)
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The realistic goal for psyllid management is
not total eradication of greening disease but
rather keeping psyllid populations at low levels
where the disease is present to reduce the rate
of disease spread