Transcript Psyllid Transmission of Greening

Entomology Research Updates
Psyllid transmission of greening
and chemical control of psyllids
Michael E. Rogers
UF / IFAS / Citrus Research and Education Center,
Lake Alfred
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
Psyllid Acquisition Rates
(laboratory studies)
• Psyllids which fed as adults on HLB (+)
plants
• Average acquisition rate of 20-30%
% infected
Greening Infected Adult Psyllids
Feeding Time (days)
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%
Psyllid Acquisition Rates
(field studies)
• Caging Studies
– Acquisition by adults vs nymphs
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
Seasonal 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
Preliminary Data (Jan-Jul 2008)
Psyllid Infection rate and sample size averaged for all Florida sites.
4500
0.5%
0.005
4000
3500
Total # psyllids sampled
0.004
3000
2500
0.003
2000
0.2%
0.002
1500
1000
0.001
500
0
Sample Size (N)
Infection Rate
0.006
Small sample
size
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
• 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
Summary 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
Summary 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
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?
Vector Management
using insecticides
• Preventing transmission
• Reducing overall psyllid populations
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?
Ongoing studies:
• imidacloprid treated and untreated
plants challenged with HLB (+)
psyllids
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
Huh?!?
Electrical Penetration Graph
(EPG) – measure psyllid feeding
EPG 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
Control of Asian citrus psyllid, citrus
leafminer and citrus rust mite
Trial 2008-10
M.E. Rogers
UF / IFAS / Citrus Research & Education
Center, Lake Alfred
Treatments
1
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%)
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
Target pest
Pesticide active
ingredient
Mode of
Action1
Psyllid
Leafminer
Rust Mites
Spider Mites
Root Weevil
Adults
Mealybugs
Effects on
natural enemies
+(oil)
+
+++,R
+++,R
+++,R
++
+ (oil)
++
+
+++,R
+
+
+
medium
medium
low
high
high
low
high
low
high
low
++
+
medium
++,R
?
?
?
+
?
?
?
low
medium/high
high
low
low
low
high (short term)
Scale Insects
Abamectin + oil
6
++
+++,R
+++,R
+
+ (oil)
Acetamiprid
4
+++,R
?
Aldicarb
1A
+++,R
+++,R
+++
Carbaryl
1A
+++,R
+
?
+++,R
Chlorpyrifos
1B
+++,R
+
+
+
Diflubenzuron
15
++
+++,R
+++,R
+++,R
Dimethoate
1B
+++
?
Fenbutatin oxide
12
+++,R
+++,R
Fenpropathrin
3
+++,R
+
+
+++,R
Imidacloprid (soil
4
+++,R
+++,R
+
application, nonbearing)
Imidacloprid (foliar
4
+++,R
+
application)
Petroleum oil
NR
+
++,R
++,R
++
+(eggs)
Phosmet
1B
+++
+
?
+++,R
Pyridaben
21
?
+++,R
+++,R
Spinosad
5
+++,R
Spinetoram
5
+++
+++,R
?
?
Spirodiclofen
23
+++,R
+++,R
?
Sulfur
NR
+++,R
+++
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
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
Imidacloprid soil drench rates for solid plantings on nonbearing citrus
Tree Height
Rate Product/A*
Imidacloprid 2F
2 ft – 4 ft
8 fl oz
4 ft – 6 ft
16 fl oz
Imidacloprid 4.6F (Admire PRO)
2 ft – 4 ft
3.5 fl oz
4 ft – 6 ft
7 fl oz
*Rates based on 140 trees per acre
Applications per season
Ounces per tree
Trees per ounce
4
2
0.057 fl oz
0.114 fl oz
17.5 trees
8.77 trees
4
2
0.025 fl oz
0.05 fl oz
40 trees
20 trees
Restricted Entry Interval (REI) and Pre-Harvest Interval (PHI) for products listed on front page
Active Ingredient
Restricted entry interval (REI)
Abamectin
12 hours
Acetamiprid
12 hours
Aldicarb
48 hours
Carbaryl
12 hours
Chlorpyrifos
5 days
Diflubenzuron
12 hours
Dimethoate
48 hours
Fenbutatin oxide
48 hours
Fenpropathrin
24 hours
Imidacloprid
12 hours
Phosmet
24 hours
Pyridaben
12 hours
Spinosad
4 hours
Spinetoram
4 hours
Spirodiclofen
12 hours
Sulfur
12 hours
Use pesticides safely. Read and follow directions on the manufacturer’s label.
Pre-harvest interval (PHI)
7 days
7 days
0; 30 days lemons
5 days
21 days
21 days
15 days
7 days
1 day
0
7 days
7 days
1 day
1 day
7 days
0
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
Acknowledgements
• Florida Citrus Production Research
Advisory Council
• Citrus Growers (numerous)
Acknowledgements
• Lab Members:
Harry Anderson
Sr. Biol. Sci.
Tim Ebert
Post-doctoral
Research Assoc.
Percivia “Peaches” Mariner
Research Assistant
Rhonda Schumann
Sr. Chemist
Antonios Tsagkarakis
Post-doctoral
Research Assoc.
Rosana Serikawa
Ph.D. Student
Dalia Shawer
Research Assistant