entomology research updates psyllid transmission of greening and chemical control of psyllids...
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Entomology Research Updates
Psyllid transmission of greening and chemical control of psyllids
Entomology Research Updates
Psyllid transmission of greening and chemical control of psyllids
Michael E. RogersUF / IFAS / Citrus Research and Education
Center, Lake Alfred
Michael E. RogersUF / IFAS / Citrus Research and Education
Center, Lake Alfred
Psyllid / HLB Studies (current progress)
Psyllid / HLB Studies (current progress)
• Pathogen acquisition by adults and nymphs– Laboratory– Field
• Seasonality of HLB infected psyllids– survey work
• Effects of insecticides on pathogen transmission
• Results of multi-pest efficacy trial
• Pathogen acquisition by adults and nymphs– Laboratory– Field
• Seasonality of HLB infected psyllids– survey work
• Effects of insecticides on pathogen transmission
• Results of multi-pest efficacy trial
Psyllid Acquisition Rates (laboratory studies)
Psyllid Acquisition Rates (laboratory studies)
• Psyllids which fed as adults on HLB (+) plants
• Average acquisition rate of 20-30%
• Psyllids which fed as adults on HLB (+) plants
• Average acquisition rate of 20-30%
Greening Infected Adult Psyllids
% in
fect
ed
Feeding Time (days)
Psyllid Acquisition Rates (laboratory studies)
Psyllid Acquisition Rates (laboratory studies)
• Adult psyllid reared on HLB (+) plants (nymphs fed entire time on infected plant)
• Percentage of HLB (+) adult psyllids ranged from 11.6% to 100%
• Adult psyllid reared on HLB (+) plants (nymphs fed entire time on infected plant)
• Percentage of HLB (+) adult psyllids ranged from 11.6% to 100%
Psyllid Acquisition Rates (field studies)
Psyllid Acquisition Rates (field studies)
• Caging Studies– Acquisition by adults vs nymphs
• Caging Studies– Acquisition by adults vs nymphs
Psyllid Acquisition Rates (field studies)
Psyllid Acquisition Rates (field studies)
• Adult psyllids caged on HLB (+) plants– 1 out of 1,000+ psyllids tested HLB (+)
• Adult psyllids reared from nymphs on HLB (+) plants– Percentage of adults testing HLB (+) ranged from 0%
to 100%– Variation probably due to differences in pathogen
levels in different parts of the plant
• Adult psyllids caged on HLB (+) plants– 1 out of 1,000+ psyllids tested HLB (+)
• Adult psyllids reared from nymphs on HLB (+) plants– Percentage of adults testing HLB (+) ranged from 0%
to 100%– Variation probably due to differences in pathogen
levels in different parts of the plant
Seasonal Psyllid Infection RatesSeasonal Psyllid Infection Rates• Monthly collections of “wild” psyllid
populations
• DNA extraction / PCR of psyllids to detect presence of HLB pathogen
• 8 grove sites in 5 Florida counties including:– DeSoto, Highlands, Okeechobee, Polk and St. Lucie
counties
• HLB (+) trees have been found in all of these locations
• Monthly collections of “wild” psyllid populations
• DNA extraction / PCR of psyllids to detect presence of HLB pathogen
• 8 grove sites in 5 Florida counties including:– DeSoto, Highlands, Okeechobee, Polk and St. Lucie
counties
• HLB (+) trees have been found in all of these locations
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Jan Feb Mar Apr May Jun Jul Aug
0
0.001
0.002
0.003
0.004
0.005
0.006
Infe
ctio
n R
ate
Sam
ple Size (N
)
Total # psyllids sampled
Psyllid Infection rate and sample size averaged for all Florida sites.
Preliminary Data (Jan-Jul 2008)
0.2%
0.5%
• the highest monthly infection rate found in a single grove thus far was 1.6%; high number of HLB (+) trees
• No infected psyllids were found in most groves; these groves did have varying degrees of HLB management programs
Small sample size
Summary of Results…to dateSummary of Results…to date• Overall psyllid infection rates in
the field are likely less than 1%
• Only saw rates >1% where HLB infected trees were still present
• There may indeed be some fluctuation in abundance of infected psyllids throughout the year – preliminary data
• Overall psyllid infection rates in the field are likely less than 1%
• Only saw rates >1% where HLB infected trees were still present
• There may indeed be some fluctuation in abundance of infected psyllids throughout the year – preliminary data
Summary of Results…to dateSummary of Results…to date
• Acquisition rates by adult psyllids in field appear to be low
• Higher rates in lab (plant health)
• Very high rates of infection are possible from adults reared as nymphs on HLB (+) plants; will vary based on HLB levels in plant
• Acquisition rates by adult psyllids in field appear to be low
• Higher rates in lab (plant health)
• Very high rates of infection are possible from adults reared as nymphs on HLB (+) plants; will vary based on HLB levels in plant
Implications for Managing HLB ?Implications for Managing HLB ?
• IF…you cant control 100% of the psyllids 100% of the time
• IF…100% (or even 50%) of the psyllid nymphs on HLB (+) trees acquire the pathogen
• CAN HLB be managed without removing infected trees?
• IF…you cant control 100% of the psyllids 100% of the time
• IF…100% (or even 50%) of the psyllid nymphs on HLB (+) trees acquire the pathogen
• CAN HLB be managed without removing infected trees?
Vector Management using insecticides
Vector Management using insecticides
• Preventing transmission
• Reducing overall psyllid populations
• Preventing transmission
• Reducing overall psyllid populations
Can insecticides prevent pathogen transmission?Can insecticides prevent pathogen transmission?
• Soil-applied systemic insecticides– Mortality caused by feeding prior to transmission?
• Foliar insecticides– Does contact with residues cause mortality prior to
transmission?
• If insecticides can prevent transmission, how long does such protection last?– Effects of residue degradation?
• Soil-applied systemic insecticides– Mortality caused by feeding prior to transmission?
• Foliar insecticides– Does contact with residues cause mortality prior to
transmission?
• If insecticides can prevent transmission, how long does such protection last?– Effects of residue degradation?
Ongoing studies:Ongoing studies:
• imidacloprid treated and untreated plants challenged with HLB (+) psyllids
• imidacloprid treated and untreated plants challenged with HLB (+) psyllids
Ongoing studies:Ongoing studies:• Currently holding more than 100
plants; no PCR positives to-date
• Positive transmission results could take 8-12 months
• Early symptoms can be a bit confusing
• Currently holding more than 100 plants; no PCR positives to-date
• Positive transmission results could take 8-12 months
• Early symptoms can be a bit confusing
Huh?!?
Electrical Penetration Graph (EPG) – measure psyllid feedingElectrical Penetration Graph (EPG) – measure psyllid feeding
EPG StudiesEPG Studies
• Determine exact feeding time required for pathogen transmission / acquisition
• Determine whether insecticides can disrupt feeding prior to transmission
• Determine how long insecticides (residues) provide disruption of psyllid feeding / pathogen transmission
• Determine exact feeding time required for pathogen transmission / acquisition
• Determine whether insecticides can disrupt feeding prior to transmission
• Determine how long insecticides (residues) provide disruption of psyllid feeding / pathogen transmission
Control of Asian citrus psyllid, citrus leafminer and citrus rust mite
Trial 2008-10M.E. Rogers
UF / IFAS / Citrus Research & Education Center, Lake Alfred
Treatments1 Dimethoate 4E + LI 700 1 pint/A ; 0.25% v/v
2 Dimethoate 4E + LI 700 2 pints / A ; 0.25% v/v
3 Agri-mek 0.15EC + FC 435 oil 20 oz / A ; 2% v/v
4 Agri-mek 0.15EC + FC 435 oil 10 oz / A ; 2% v/v
5 Sevin XLR + LI 700 2 quarts/A ; 0.25% v/v
6 Provado 1.6F + LI 700 10 oz / A ; 0.25% v/v
7 Movento 240SC + LI 700 10 oz / A ; 0.25% v/v
8 Movento 240SC + FC 435 oil 10 oz / A ; 3% v/v
9 Envidor 240SC 15 oz / A
10 Imidan 70W + LI 700 1.5 lbs / A ; 0.25% v/v
11 Mustang 1.5EW 4.3 oz / A
12 Danitol 2.4EC 16 oz / A
13 Micromite 80WGS + FC435 oil 6.25 oz / A ; 2% v/v
14 Portal 0.4EC + FC 435 oil 4 pints / A ; 2% v/v
15 Delegate 25WG + FC 435 oil 4 oz / A ; 2% v/v
16 Lorsban 4E 5 pints / A ; 2% v/v
17 Untreated ---
Trial Location• ConservII – MidFlorida Citrus Research
Foundation Grove• Variety – ‘earlygold’• Treatment dates: June 24-25, 2008• Trial still under evaluation (8/8/08)• Plot size: 15 trees (3 x 5)• A foliar fertilizer was tank-mixed with all
treatments • (DiamondR Ultra M2F; Sulfur 3.2%; Iron 1.6%; Mn
2.0%; Zn 2.4%)
Pesticide active ingredient
Target pestEffects on
natural enemiesMode of Action1 Psyllid Leafminer Rust Mites Spider Mites Root Weevil
Adults Scale Insects Mealybugs
Abamectin + oil 6 ++ +++,R +++,R + + (oil) +(oil) + (oil) mediumAcetamiprid 4 - +++,R - - ? + ++ mediumAldicarb 1A +++,R - +++,R +++ - - - lowCarbaryl 1A +++,R - + ? +++,R +++,R + highChlorpyrifos 1B +++,R + + - + +++,R +++,R highDiflubenzuron 15 ++ +++,R +++,R - +++,R - - lowDimethoate 1B +++ - - - ? +++,R + highFenbutatin oxide 12 - - +++,R +++,R - - - lowFenpropathrin 3 +++,R - + + +++,R - + highImidacloprid (soil application, nonbearing)
4 +++,R +++,R - - + ++ + low
Imidacloprid (foliar application)
4 +++,R + - - - ++ + medium
Petroleum oil NR + ++,R ++,R ++ +(eggs) ++,R + lowPhosmet 1B +++ - + ? +++,R ? ? medium/highPyridaben 21 - ? +++,R +++,R - - - highSpinosad 5 - +++,R - - - - - lowSpinetoram 5 +++ +++,R - ? ? ? ? lowSpirodiclofen 23 - - +++,R +++,R ? - - lowSulfur NR - - +++,R +++ - ? ? high (short term)1Mode of action class for citrus pesticides from the Insecticide Resistance Action Committee; NR = no resistance potential(R) = product recommended for control of pest in Florida Citrus Pest Management Guide(+++) = good control of pest(++) = short-term control of pest(+) = low levels of pest suppression(-) = no observed control of pest(?) = insufficient data available
List of insecticides and miticides recommended for use in the Florida Citrus Pest Management Guide and their effects on citrus pests and their natural enemies
For more information, contact the University of Florida, IFAS, Citrus Research and Education Center 863-956-1151, www.crec.ifas.ufl.edu, or your local county citrus extension agent.
Created by: Michael E. Rogers, revised August 2008
Photo Credit: University of Florida
Tree Height Rate Product/A* Applications per season Ounces per tree Trees per ounceImidacloprid 2F2 ft – 4 ft 8 fl oz 4 0.057 fl oz 17.5 trees4 ft – 6 ft 16 fl oz 2 0.114 fl oz 8.77 treesImidacloprid 4.6F (Admire PRO)2 ft – 4 ft 3.5 fl oz 4 0.025 fl oz 40 trees4 ft – 6 ft 7 fl oz 2 0.05 fl oz 20 trees*Rates based on 140 trees per acre
Imidacloprid soil drench rates for solid plantings on nonbearing citrus
Active Ingredient Restricted entry interval (REI) Pre-harvest interval (PHI)Abamectin 12 hours 7 daysAcetamiprid 12 hours 7 daysAldicarb 48 hours 0; 30 days lemonsCarbaryl 12 hours 5 daysChlorpyrifos 5 days 21 daysDiflubenzuron 12 hours 21 daysDimethoate 48 hours 15 daysFenbutatin oxide 48 hours 7 daysFenpropathrin 24 hours 1 dayImidacloprid 12 hours 0Phosmet 24 hours 7 daysPyridaben 12 hours 7 daysSpinosad 4 hours 1 daySpinetoram 4 hours 1 daySpirodiclofen 12 hours 7 daysSulfur 12 hours 0Use pesticides safely. Read and follow directions on the manufacturer’s label.
Restricted Entry Interval (REI) and Pre-Harvest Interval (PHI) for products listed on front page
Additional citrus pest management information can be found in the Florida Citrus Pest Management Guide available online at http://www.crec.ifas.ufl.edu/extension/pest/index.htm
AcknowledgementsAcknowledgements
• Florida Citrus Production Research Advisory Council
• Citrus Growers (numerous)
• Florida Citrus Production Research Advisory Council
• Citrus Growers (numerous)
AcknowledgementsAcknowledgements• Lab Members:• Lab Members:
Harry AndersonSr. Biol. Sci.
Percivia “Peaches” MarinerResearch Assistant
Rhonda SchumannSr. Chemist
Dalia ShawerResearch Assistant
Tim EbertPost-doctoral
Research Assoc.
Antonios TsagkarakisPost-doctoral
Research Assoc.
Rosana SerikawaPh.D. Student