Title: Citrus industry update
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Permanent Link: http://ufdc.ufl.edu/UF00086519/00007
 Material Information
Title: Citrus industry update
Series Title: Citrus industry update
Physical Description: Serial
Language: English
Creator: Institute of Food and Agricultural Sciences, University of Florida
Publisher: University of Florida Institute of Food and Agricultural Sciences
Place of Publication: Gainesville, Fla.
Publication Date: August/September 2008
 Record Information
Bibliographic ID: UF00086519
Volume ID: VID00007
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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Citrus Industry Update

To Keep You

Published by the University of Florida, Institute of Food and Agricultural Sciences, with the mission
of keeping the Florida Citrus Industry informed of current research concerning canker and greening.

Dormant Season Sprays: Successful Strategy to
Reduce Psyllids into the Growing Season
Jawwad Qureshi and Phil Stansly

In 2007, two 15-acre plots within two 60+ acre
blocks of mature orange trees were sprayed
with Lorsban 4 E at the rate of 5 pints per acre
by ground on Jan 15. We observed that psyllid
populations were suppressed for 6 months in
the treated blocks compared to the untreated
blocks. The 2008 experiment compared three
one-application and one two-application
treatments replicated four times in the same
blocks. Applications were made by ground at
the per acre rate of 1 (low) and 2 (high) quarts
of Vydate 2 L, 5 pints of Lorsban 4 E, and 1 pint
of Danitol 2.4 EC; all made on Jan 16-17. The
two-application treatment included ground
applications of Danitol 2.4 EC on Jan 16-17 and
Lorsban 4 E on Feb 15. All treatments except
the low rate of Vydate reduced psyllid
populations for 5 months. Effects were more
pronounced on the adults than flush infestation
or nymphal density. The application of Vydate
2 L and Danitol 2.4 EC and of Danitol 2.4 EC
followed by Lorsban 4 E provided more
suppression of psyllids than Lorsban 4 E by
itself. There was no difference in the
effectiveness of single application of Danitol
2.4 EC and the one that was followed by
Lorsban 4 E, probably due to the short time
interval between the two applications.
However, both of these treatments performed
better than the low rate of Vydate 2 L. There
were no discernable treatment effects on
ladybeetles that were common in both treated
and untreated trees. These findings suggest
that one or two applications of broad spectrum
insecticides before spring flush significantly
reduced psyllid populations for 5-6 months in
the growing season. Therefore, the winter
dormant season appears to be a safe and
effective time to control psyllids with
insecticides. Most predators are absent during

that period or in the case of many parasitoids
protected inside their hosts. Adult psyllids are
fewest and most vulnerable. Additional sprays
in the growing season should be based on
scouting and made prior to anticipated flushes.

Insecticidal Control of Asian Citrus Psyllid and
Citrus Leafminer: May 2008
Jawwad Qureshi, Barry Kostyk,
and Phil Stansly

At Southwest Florida Research and Education
Center (SWFREC), Immokalee, Florida, 13-yr-old
'Valencia' orange trees were pruned manually
to induce new flush and encourage psyllid
infestation. Danitol 2.4 EC (21.3 oz/ac),
Agri-Mek 0.15 EC + 435 Oil (20 oz + 2%/ac),
Warrior 1 SC (5.75 oz/ac), Actara 25 WG
(5.5 oz/ac), Actara 25 WG + Induce (5.5 oz +
0.1%/ac), Micromite 80 WGS + 435 Oil (6.25 oz
+ 2%/ac), and Micromite 80 WGS + 435 Oil
(3.125 oz + 2%/ac) were applied on May 22,
2008 using a Durand Wayland 3P-10C-32
airblast speed sprayer with an array of six #5
T-Jet stainless steel cone nozzles per side
operating at a pressure of 200 psi delivering
150 gpa at a tractor speed of 1.5 mph. The
second application of the low rate of Micromite
was made on June 12, 2008. The density of
psyllid adults was estimated by using a "tap"
sample made by striking with the hand
a randomly chosen branch three times and
counting individuals falling on a clipboard
covered with an 8.5" x 11" white paper sheet.
All treated trees had significantly fewer adults
compared to untreated trees for 6 weeks. The
percentage of flush infested with psyllid eggs
was significantly reduced by all treatments for
only 1 week. However, the percentage of flush
infested with psyllid nymphs was significantly
reduced by all treatments for 3 weeks. All
treatments resulted in fewer mature nymphs
2008 Citrus Research and Education Center, University of
Florida, Institute of Food and Agricultural Sciences, 700 Experiment
Station Road, Lake Alfred, FL 33850, Phone: 863-956-1151.

Citrus Industry Update
Community Service Bulletin

August / September 2008


Augs / Setebe 2008i

seen on the treated trees compared to
untreated trees for 4 weeks. Micromite
treatments were less effective compared to all
the other treatments during the third week.
Thus, all treatments reduced adults and had
some effect on nymphs for 6 weeks. The one-
time application of the high rate of Micromite
80 WGS with 435 Oil provided better control
than the low rate with 435 Oil applied twice
during the same period. No significant
improvement in performance of Actara 25 WG
was observed in combination with Induce.

All treatments except Actara 25 WG alone and
Warrior 1 SC reduced leafminer populations for
2 weeks. Agri-Mek 0.15 EC + 435 Oil and
Danitol 2.4 EC were the most effective
treatments. Actara 25 WG + Induce resulted in
better control than Actara 25 WG applied

Commercial-Scale Aerial and Ground
Applications to Control Adults of Asian
Citrus Psyllid in Oranges
H. Alejandro Arevalo, Phil Stansly
(UF-IFAS-Immokalee) and
Henry Yonce (KAC Agricultural Research, Inc.)

The effectiveness of 10 insecticide treatments
applied by fixed wing aircraft and five by
conventional airblast ground equipment + an
untreated control was evaluated for 5 weeks
after application in two adjacent blocks of
Valencia oranges located in Collier Co., Florida.
Aerial applications were made to single 10-bed,
12-acre plots at 10 gal/ac and ground
treatments to single 3.8-acre plots at
125 gal/ac. Adult psyllid populations were
monitored on 10 trees selected at random
toward the middle of two central beds in each
plot for a total of 20 trees per treatment.
Branches of trees in two locations were tapped
three times, and the number of adult psyllids
falling on a letter-size 8.5" x 11" white sheet of
paper was recorded. Treatments evaluated by
air and ground included: Delegate (4 oz/ac,
Delegate + Oil (4 oz + 3gal/ac), Imidan + Oil
(1.0 oz + 3 gal/ac), Imidan + Oil (1.5 oz +
3 gal/ac), and Provado + Joint Ventura (16 oz +
8 oz/ac). Additional aerial applications included
Danitol (16 oz/ac), Danitol + Joint Ventura

(16 oz + 8 oz/ac), Mustang (4.3 oz/ac), Mustang
+ Micromite (4.3 oz + 6.25 oz/ac), and Mustang
+ Joint Ventura (4.3 oz + 8 oz/ac).

Initial populations were high, averaging 3.5 per
two-tap sample. Although the design precluded
statistical analysis, some clearly defined trends
were evident. Counts for the untreated control
averaged almost eight for the entire study
period. The best aerial treatments were those
including Danitol and Imidan, reducing
populations to below one per sample for the
entire study period. Applied by ground, Imidan
and Delegate + Oil essentially eliminated adult
psyllids. Delegate alone and Provado + Joint
Ventura also performed well by ground but did
poorly by air. This trial demonstrated that while
aerial application can give comparable results
to ground application with at least some broad
spectrum insecticides, certain selective
insecticides provide much better results when
applied by conventional ground equipment.

Management of Asian Citrus Psyllid with
Frequent Ultra-Low Volume Applications
(Fogging) of Oil and Azadirechtin
During the Growing Season
H. Alejandro Arevalo and Phil Stansly

Most products with insecticidal properties have
label restrictions which do not allow them to be
used as ultra-low volume (ULV) applications in
citrus. Horticultural mineral oil (HMO) and
azadirechtin (Aza-Direct), a botanical
insecticide derived from the neem tree, are
both OMRI (Organic Material Review Institute)
approved and do not have ULV restrictions. We
are evaluating three treatments replicated
three times in a 62-acre block of Valencia
oranges located in Collier Co., Florida: 1) HMO
at 1 gal/ac, 2) HMO + Aza-Direct (1 gal + 12 fl
oz/ac), and 3) an untreated control. Ultra-low
volume applications using a London Fogger
belonging to the Beck brothers are made at
night once every 2 weeks beginning July 1.
Samples are taken the day before application,
and collected in the middle section of the
central bed in each one of the treatment plots.
In each plot, 20 trees are sampled using two
tap samples per tree to determine adult Asian
citrus psyllid (ACP) populations. To determine

Citrus Industry Update
Community Service Bulletin


August / September 2

the percentage of infested flush, a maximum of
10 flush per plant are observed, the flush with
eggs or nymphs present are recorded, and an
estimation of the flush concentration is
calculated by counting the number of flush
found in a 30 x 30 cm PVC square placed over
the area where the tap samples are conducted.
The initial psyllid population was extremely low
after two aerial applications of broad spectrum
insecticides. Although we have yet to observe a
resurgence of adult Asian citrus psyllids in the
first 2 months after the first fogging
application, we have seen significantly less
infested flush on treated trees compared to
untreated trees, with no differences between
HMO and HMO + Aza-direct treatments. We
plan to continue this trial into the fall to see if
differences accentuate. The hope is that these
treatments will maintain psyllid populations at
low levels during the growing season.

Casuarina Given a Second Chance for
Use as a Windbreak
Bill Castle
Persistent efforts to allow the propagation of
Casuarina cunninghamiana for use as
a windbreak in citrus have paid off. Legislation,
promoted by growers, was passed this summer
that allows for restricted vegetative
propagation of male C. cunninghamiana. There
are three species of the non-native Australian
pine (Casuarina spp.) in Florida. Their spread in
some areas of the state had resulted in each
species being classified by the Florida
Department of Environmental Protection as
invasive and subject to removal.

The new law allows only vegetative
propagation of Florida sources of male
C. cunninghamiana plants for use as
windbreaks in citrus groves in Martin, St. Lucie,
and Indian River counties only. The Florida
Department of Agriculture and Consumer
Services, Division of Plant Industry, is the
rule-making and regulatory authority.

If you intend to commercially propagate this
plant, it is highly recommend that you review
previous studies on rooting cuttings to best
understand the various treatments attempted
by others. Also, our efforts at the CREC to root

cuttings have met with limited success.
A summary of propagation attempts and
results at the CREC as well as links to relevant
literature are available by clicking on the
"Casuarina Propagation" link at

For questions and
contact Dr. Bill

further details, please
Castle: 863-956-1151,

New Publications and Tools Available for
Greening Scouting
Tim Spann

A new EDIS publication is available titled,
"Scouting for Citrus Greening." This document
describes current recommendations for
scouting frequency and the advantages and
disadvantages of various scouting methods.
Also included is a detailed review of greening
symptoms and recommendations for utilizing
the field-friendly iodine-based starch test
detailed in a separate EDIS document. The
scouting document can be downloaded at
http://edis.ifas.ufl.edu/CH200, and the iodine
test is at http://edis.ifas.ufl.edu/HS375.

A new tool in the final development stages is an
online training program for scouts. This
interactive training will allow new scouts to
learn the history, spread, and identification of
citrus greening through a self-paced online
tutorial and is available in both English and
Spanish. Growers can evaluate their scouts'
ability through a series of greening
identification quizzes and short answer
questions, the results of which are emailed
directly to the supervisor. Growers can also use
the training program as a refresher course for
their scouts as needed and in between in-
person training by IFAS personnel. The final
technical glitches are currently being ironed
out, and this new tool will be available for use
through the CREC website in a couple of weeks.

For questions and further details, please
contact Dr. Tim Spann: 863-956-1151,

Citrus Industry Update
Community Service Bulletin


Auus / 6 Setm e 2008

Citrus Expo 2008 (Seminars Only)
September 4, 2008
UF/IFAS Citrus Research and Education Center,
Lake Alfred, Florida 33850
For more information, visit www.citrusexpo.net

Packinghouse Day
September 11, 2008
UF/IFAS Citrus Research and Education Center
700 Experiment Station Road, Lake Alfred,
Florida 33850
For more information, visit the postharvest
website or contact Mark Ritenour, 772-468-
3922 ext. 167 or via email, ritenour@ufl.edu

Postharvest Workshop
September 16, 2008
UF/IFAS Indian River Research and Education
Center, 2199 South Rock Road, Fort Pierce,
Florida 34945
For more information, visit the postharvest
website or contact Mark Ritenour, 772-468-
3922 ext. 167 or via email, ritenour@ufl.edu

FNATS: The Landscape Show
September 25-27, 2008
Orlando, Florida
For more information, visit

Florida Ag Expo
November 5, 2008
UF/IFAS Gulf Coast Research and Education
Center, Balm, Florida 33503
For more information and registration, visit

International Research Conference on HLB:
Reaching Beyond Boundaries
December 1-5, 2008
Orlando, Florida
For more information and registration, visit
http://www. doacs.state. fl. us/pi/hlb conference/

Florida Mini-Greening Summit
Presented by the Florida Cooperative Extension
Service Citrus Extension Agents
10 a.m. 12 p.m. (Agenda)

* September 30, 2008 Lake County Extension,
Tavares. To register, contact the Lake County
Extension Service 352-343-4101

* October 2, 2008 Highlands County
Extension, Sebring. To register, contact the
Highlands County Extension Service 863-402-

* October 7, 2008 Southwest Florida
Research and Education Center, Immokalee.
To register, contact the Hendry County
Extension Office 863-674-4092

* October 8, 2008 Turner Exhibition Hall,
Arcadia. To register, contact the DeSoto
County Extension Service 863-993-4846

* October 9, 2008 Polk County Extension
Stuart Center, Bartow. To register, contact
the Polk County Extension Service 863-519-
8677 ext. 111

* October 14, 2008 Indian River Research and
Education Center, Ft. Pierce. To register,
contact the St. Lucie County Extension Office

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