The Mission of UF/IFAS is to develop
knowledge in agricultural, human and
natural resources and to make that
knowledge accessible to sustain and
enhance the quality of human life.
Spring 2009 UF
April, May & June
Lake County Extension
It has been a long winter season. I for one am glad to see the spring time arrive. We had two freeze events
this winter. Thankfully we had a good bit of cool weather in the fall to help condition the trees and lower the
leaf freezing points. There were still individual groves that suffered some fruit and tree losses. Already you
can see trees that lost leaves coming back strong, with all this young flush comes ideal habitat for the Asian
citrus psyllid. As always controlling psyllid populations, scouting your groves for HLB symptoms and re-
moval of inoculum sources are key in today's citrus production. Your extension program has been heavily fo-
cused on the HLB issue for the past few years and with the amount of research on-going in this area, hopefully
there will continue to be new recommendations to maximize citrus production and sustain tree health.
COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, Larry R.
Arrington, Director, in cooperation with the United States Department of Agriculture, publishes this information to further the purpose of the May 8
and June 30, 1914 Acts of Congress; and is authorized to provide research, educational information, and other services only to individuals and insti-
tutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, na-
tional origin, political opinions, or affiliations. Single copies of extension publications (excluding 4-H and youth publications) are available free to
Florida residents from county extension offices. Information about alternate formats is available from IFAS Communication Services, University of
Florida, PO Box 110810, Gainesville, FL 32611-0810.
Well this year started off with two hard
freeze events on January 21-22 and
February 5-6. As one grower said "at
least it was a democratic freeze" mean-
ing that the whole state got to share the
sleepless nights. Looking at FAWN
temperature data for two locations
(Umatilla and Avalon) between January
1st to March 1st; Umatilla had total of 69
Pictured above: Some tree damage from radiation freeze event. Tempera-
hours and Avalon a total of 35 hours at
tures are colder in low elevation areas. This happen to be a depressed area in
or below 32 degrees. Thankfully we the grove. Trees lost their leaves but are currently recovering with new
flush. Below: A close up of the same area as the picture above. Trees
had a unseasonably cool October and started to lose their leaves, but this spring trees began pushing out new
November which helped to hardened
the trees and reduced there leaf freez-
ing points allowing most of our trees to
pull through the freeze events relatively
unscathed (for more information on
2009 leaf freezing point data please
However, there was some damage as I am sure you are aware. The coldest temperatures re-
corded at the FAWN sites were 28 for Avalon
(recorded on 1/22) and 23 for Umatilla (recorded
2/6). In speaking with growers around those areas
and the state, there were some temperatures as
low as 17 or 18 in low cold pockets. I heard grow-
Pictured left: These lemon trees were in a protected structure but still
suffered some foliage damage. They were trimmed up and are al-
ready back to health.
ers as far south as LaBelle and Martin
County that experienced similar
temperatures in small isolated areas.
Of course we have known that using
irrigation for cold protection can be
beneficial during freeze events, par-
ticularly radiation events which do
not have much wind. The process of
water turning to ice is called heat of
fusion. As long as you are constantly
fusion. As long as you are constantly Pictured above: This grove did not have the capability to cold protect the entire
turning water to ice you can maintain grove. The row to the left of the middle had irrigation for cold protection
whereas the row to the right of the middle did not have irrigation for cold pro-
temperatures at or near 32 degrees. tection.
One of the problems in using irrigation for freeze protection during windy nights with low hu-
midity is the chance of evaporative cooling taking place. Evaporative cooling occurs when wa-
ter instead of freezing evaporates (heat of vaporization). When it evaporates it takes with it 7.5
times more heat than is being produced by water freezing. So for every gallon of water that
evaporates, it takes 7.5 gallons of water to freeze to balance out the heat lost to evaporation.
When using microsprinklers for cold protection, the higher the volume of water applied to the
Pictured below: Classic radiation freeze in which high elevation have higher tem- tree the more effective it will be
peratures which can protect trees from potentially damaging temperatures. The
picture shows the effect of elevation can have on a cold night. (see graph on page 5). Water can
be an effective tool in the protec-
tion of crops when systems are op-
erating properly and environ-
mental condition lend to effective
use of water. Using leaf freezing
point data, having a reliable
weather forecast and being pre-
pared all are critical in minimizing
damage from freezes.
Pictured left: These young trees were planted a few weeks before the first freeze event. This
grower ran water during both nights of 1/22 & 1/23 the trees were iced in well and sustained
no damage Pictured below Same -rovc as the tree to the lcft with irrigation svstcm protect-
I \ OLI11h 2 IC. dLIIIIclh' fi C %/c c't\ l
- ------ -- ---- ---- --- ------- ----- ------ --- -- -
-------t --------- --l-~~- -~-.Ic-
... .- --.- -. ------- ----- ---- -
60 80 100 120 140 160 180 200 220
Tree planting density (treeslacre)
Pictured above: A young tree where water was run
all nights of both freeze events. The area that was
protected with water and had good ice formation was
relatively undamaged. While the areas that were on
the outside or edge of ice formation sustained dam-
The graph to the left is gallons per acre per hour of
water available for freeze protection based on micros-
prinkler discharge rate (ranging from 8-20 gph per
tree) and tree planting density. It can be found in
Drs. Parson and Bowman's UF publication Micros-
prinklers Irrigation for Cold Protection in Citrus. If
you would like a copy of the publication please con-
tact our extension office.
A Summary: Georeferenced Ground Photography of Citrus Orchards to Estimate
Yield and Plant Stress for Variable Rate Technology
Arnold W. Schumann, Kevin Hostler, Juan Carlos Melgar and James Syvertsen Proc. Fla. State Hort. Soc.
In honor of FSHS meeting coming up in June I would like to summarize the paper that won the
"best paper" award in the citrus section from the 2007 meeting. I also ties into our recent OJ fer-
tilization meeting. Variable rate application uses optic and ultrasonic sensors to measure citrus
tree canopies. These technologies can save money by only applying fertilizer or chemicals in a
grove to space that is occupied by trees. The research in this paper experiments using variable
rate technology (VRT) to measure fruit load, flower intensity, and nutrient stress in the tree can-
opy. Additionally, the researchers looked at determining early water related stress before leaf
wilting becomes visible using VRT and the possibility of disease detection. The overall objec-
tive was to determine the potential uses of
georeferenced digital photography in citrus Yield index
production. = (fruit pixels per unil of carnpy x canopy volu me)
Y 2_B77X + 10M3
Researchers used a digital camera mount on R2.alf"
a vehicle to take pictures of the entire grove. ++ .Wsus /
Using the images colors, they determined the A A AVa.ssAm
amount of mature fruit and canopy volume (I -
am keeping the description simple for all the
details see paper). When using pictures of
mature fruit or canopy volume to predict fruit -
yield they had a weak relationship. However,
when using both images of mature fruit and -
canopy volume together the found they could Defoliated trees (not used in regression)
predict fruit yield in Hamlin and Valencia
groves (see figure 1). The calculation of in- o o t no s
dividual tree fruit yield can then be used for Y'eM lc (h-*opW EvoLu pkd*)
site specific variable rate application of agro- Figure 1 (Figure 10 in FSHS proceedings). Relationship between
chemicals. Basically giving each tree only fruit yield per tree and the yield index calculated from percent fruit
pixels and canopy volume of each tree.
what it needs based on it fruit yield, which in-
creases the productivity of your operation. Increased productivity is key for maximizing returns.
This digital images were also used to determine a relationship with water stress and disease de-
tection. Repeated annual measurements using this technology could potentially be used to track
the spread of disease (blight was used as an example in paper). This technology may hold po-
tential in the future for detecting and tracking the spread of canker or greening.
Mid Florida Citrus Foundation's
A.H. Krezdorn Grove Field Day
May 14th 9:00-11:30 AM
We will be having a field day at the Mid Flor-
ida Citrus Foundation's (MFCF) A.H. Krezdorn
grove on May 14th from 9:00-11:25. This the
second of two field days this year in which re-
searchers will provide an update on their cur-
rent research trials conducted at the MFCF.
Topics will include psyllid control chemical
trials and applicator trials, herbicide trials,
open hydroponic system research, wind-
breaks, and a low volume applicator demon-
stration. There will also be a discussion on
peach production and fruit evaluation.
9:00-9:30 Peach production and tasting
OHS experiment and
-Dr. Bill Castle
Psyllid control experimental
-Dr. Lukasz Stelinski
10:25-10:45 Psyllid control trials
-Dr. Michael Rogers
10:45-11:05 Herbicide research results and
-Dr. Steve Futch
11:05-11:25 Low volume applicator
Please call Maggie at 352-343-4101 so we
know how many handouts and drinks we will
need. Bring a lawn chair if you want to sit!
The Greening Summit at the Grower's
Institute Polk County Agricultural
Center -Bartow April 7th
Citrus Greening or Huanglongbing (HLB) con-
tinues to spread throughout the citrus produc-
tion areas of Florida. The symposium is an op-
portunity for Florida Citrus Growers to come
together under a single purpose to effectively
manage this devastating disease. Topics this
year include production systems, plant im-
provement, vector management, horticultural
responses to HLB, disease detection and
Continuing Education Units (CEU's) will be of-
fered for holders and restricted use pesticide
licenses (RUP) or certified crop advisors (CCA).
CEU's will be offered for the following catego-
ries: private, agricultural tree, regulatory, dem-
onstration and research for RUP holders.
CCA's will be offered CEU's in the pest man-
agement category.. Registration is limited to
the first 300 participants. Sign up sheet was
Florida State Horticultural Society An-
nual Meeting June 7-9 Jacksonville
This years Florida State Horticultural Society
Annual Meeting is being held in Jacksonville,
FL at the Windham Riverwalk. The early regis-
tration deadline is April 15th. You can obtain
additional information and register thru the
FSHS website http://www.fshs.org/
meetings.htm. The annual meeting provides
growers with a great opportunity to interact
with researchers. I encourage everyone to be-
come a member of FSHS and/or attend the an-
Citrus Research and Education Center Tour June 17th 9:30-4:00
On June 17th we will be touring the University of Florida's Citrus Research and Education Center
(CREC) in Lake Alfred. The center houses IFAS and DOC research employees, has over 600
acres of research grove, multiple greenhouses, a fresh fruit packinghouse, a pilot juice process-
ing plant and the world's largest citrus library. A free lunch will be provided, registration is re-
quired please call Maggie at 352-343-4101 to sign up.
Linda Murphy Welcome to the CREC 9:30 a.m.
Dr. Reza Ehsani Precision Tech. Lab/Grove Tour 9:35 10:15
Dr. Fred Gmitter RES/Advance Breeding Greenhouse 10:20 11:00
Dr. Ron Brlanskv Greenhouse/Plant Pathology Lab Tour 11:05 11:45
Break for lunch 11:50 1:00
Dr. Bill Dawson Screening Greenhouse Tour 1:05 -1:45
Dr. Jude Grosser Cell Genetics/Plant Improvement Lab Tour 1:50 -2:30
Dr. Lukasz Stelinski Entomology/Nematology Lab Tour/Psllid Rm. 2:35 -3:15
John Henderson Packinghouse/Pilot Plant Tour 3:20 -3:45
CEU Day -June 10th Mid Florida Research and Education Center Starts at 8:30
If you are in need of CEU's to renew your pesticide license here is your chance to get a few in
one location. We will be holding one of our two annual CEU Day events in Apopka at the Mid
Florida Research and Education Center. Call Seminole County Extension to register 407-665-
CEU's offered include General Standards/CORE, Private Applicator, Agricultural Tree Crop and
more. Sign in starts at 8:15 and Session 1 begins at 8:30AM. There is a charge of $20 per two
hour session. In the afternoon will be Worker Protection Standards Train the Trainer session for
those that would like to have a WPS training card. You do not need a WPS training card if you
have a valid pesticide license.
Private Agricultural License Review & Exam May 20th 8:30-4:00
A pesticide license is required by any persons who apply or supervise the application of re-
stricted use pesticides for agricultural production. This certification requires a passing grade of
70% on the General Standards and Private exam. This certification must be renewed ever 4
years either by testing or by 8 CEU's. There will be a review and exam in Kissimmee on May
20th. The review starts at 8:30 AM. There is a $20 charge for the class. It is advisable to pur-
chase the "Applying pesticides correctly" and "The private applicator training manual" from the
IFAS bookstore on-line at www.ifasbooks.ufl.edu or by calling 800-226-1764. We also recently
donated all pesticide books to the Lake County library system, so they can be checked out. The
private agricultural license itself cost $100 which does not have to be paid until after you pass
the exam. To register please call Jennifer Welshans at 321-697-3000.
Mr. Florida Citrus-Jerry Chicone elected to Citrus Hall of Fame.
Th a Departmel Jerry Chicone aka "Mr. Florida Citrus" was inducted
to the Citrus Hall of Fame this past month. The event
was held at Florida Southern College which is the
host site of the Citrus Hall of Fame. Mr. Chicone has
a wonderful history of fighting for the Florida citrus
growers well being and is known for his coined slo-
gan "squeeze oranges not growers". This year was
the first Citrus Hall of Fame event that I had the privi-
lege of attending. It was a great honor to participate
in the event. I would encourage anyone connected
to the Florida Citrus Industry to take some time to
visit the Florida Citrus Hall of Fame, it is worth your
effort. I personally want to congratulate Mr. Chicone
on a well deserved honor. Thank you for your sup-
port of the Florida Citrus Industry!
La Nina returns to Pacific which usually impacts Florida agriculture
La Nina has returned to the Pa-
cific Ocean. La Nina ocean
conditions mean warm dry
spring weather for Florida.
The years of 1999, 2000, and
2006 were also La Nina events.
Typically these drought condi-
tions bring on forest fires
(already being seen as of this
writing) and the need for good
irrigation systems. It might be
wise if you have yet to check
your sprinkler heads to make
sure that every tree is getting
U.S. Drought Monitor
Drought Condihons (Parcent Area)
None 0I. I: I 0 l.jJ I g014
Current 13.6 86.4 41.9 11.8 1.6 0.0
io.,oIms.,) 8.5 91.5 42.1 9.8 1.6 0.0
3 MonAh Ago
12,laMnea) 70.7 29.3 143 6.0 43 0.0
CIl(ndarYear 653 34 7 157 5.3 28 00
watr, vea 35.2 64.8 41.8 20.8 94 1.9
SWo7)Wi m2 4p) 0.
One Year Ago
Iao,1aMermap) 23.8 76.2 58.5 40.5 18.8 0.3
Dfl Abnoaral- Dry
D1 DOmighl Mrdecrat
DI Oraighi- S'n rc
March 17, 2009
Valid 7 a.m EST
1 D4 Digh Eaption.l
The Drought Monitor focuses on broad-scale conditions.
Local conditions may vary. See accompanying text summary
for forecast statements
Released Thursday, March 19, 2009
Author: Laura Edwards, Western Regional Climate Center
Pictures of recent Extension Activities
We got a good start to the new year with your extension program. There was unfortunate timing
on our Mid Florida Citrus Foundation field day which was on Jan. 22nd right after a major freeze.
Attendees learned about the latest citrus variety release, the Sugar Belle TM. Drs. Grosser,
Gmitter, Castle, Ling and Bowman also shared results of their citrus improvement research
efforts. Dr. Parsons spoke on how to improve irrigation efficeincy using new technology. Gary
England reviewed containerized blueberry and peach production in Florida.
Pictured abo\ c Di Jidk Giociss: sho" s oil ii cint ni l qtlLIllI of a sC:d-
less triploid luh icK (RE( phliil iiipio\ cimciiil ic, iiisn lucicid Tihe i1niiii
focus of the biccdiin, pnioi_', s ih ilK iC ol Ill c0illlu ildUll i i to Iillnd
a solution to lilk ,.cvicnl'I pioblci
Picltuiid ,bo\ i Bluicbci n.s lcown
III COIInIcIIhI C c ic cd III to10 protect
flowers and fruit from the freezes
with overhead irrigation.
Pictured left: Dr. Castle discuses the
results of a Midsweet and Valencia
variety trial. This trial evaluation
will most likely lead to more pro-
ductive varieties being recom-
mended for juice production.
Pictures of recent Extension Activities cont.
We had a greening field day in Osceola County. Jamie Yates and I lead everyone on identifica-
tion of symptomatic trees, trees with Phytophthora and nutritional issues, and even gave a quiz to
try to see if you could determine which trees were truly greening. Dr. Dewdney spoke about the
latest in greening research and why it is important to remove inoculum sources from your grove.
We ended it all with a low volume applicator demonstration and a talk about low volume applica-
tion research results and labeling issues concerning this technology.
Picliuicd IIcfl Paillicipal) s [i- and dtic. li.nunc hIch
kll ,I ll l IIllklp ( I: R l vlO in J l oi .2ll.llk. "Ilkll
Iicc aii .l id ii 1101o PC R po illi\ 101 l illll' SLII-
\ Ce\ IC. llsi ndiicl' d 1111 ".. ol ali lkndcs ll Illlk\
icld di'\ '"*,, ol llindiic ..s could idcinillh' ii. isc.a .
Piclticti d lb lo%\ Gio\ci. prs ii liiot_'l i ik- ic s to10
i lacl a lo'\ olllllC appJlicai|nlln Ill k' adiacci n 1o0lll 1
Lol'\ .olilc pli c a iioin i ll u.l o bililn Iro clloi .l IoId
COiliol and i~s cli ca appl'ica nn aJCn o11111 oll ic Ii di-
Pictured left: Rob Arnold
shows off his Citruscloud low
volume applicator and fields
questions on its use in groves.
Lake County Agricultural Center
1951 Woodlea Rd.
Tavares, FL 32778
Reminder: Please fill out the
post card we sent in the
mail a few weeks ago to
continue to receive Citrus-
lines newsletters. We need to
reduce the use of physical
mailing due to budget con-
straints. Thank you.
Greening bacteria sequenced
USDA researchers have sequenced the
genome of the greening bacteria. This
will allow scientists to study the bacte-
ria's genetic code and potentially give
greater understanding on how the or-
ganism is spread and how it can be
stopped. This is some much needed
good news, hopefully this is just the
first break through of knowledge in
the fight against the greening bacte-
ria. To learn more visit http://
The Vision for the University of Florida's Institute of Food and Agri-
cultural Sciences (UF/IFAS) is to increase and strengthen the knowl-
edge base and technology for:
Expanding the profitability of global competitiveness and sustain-
ability of the food, fiber, and agricultural industries of Florida.
Protecting and sustaining natural resource and environmental sys-
Enhancing the development of human resources.
Improving the quality of human life.
New aerial label for Agri-Mek
Syngenta Crop Protection has received approval for
the aerial application of Agri-Mek Miticide/
Insecticide for the control of citrus leafminer to aid in
the management of citrus canker. This label is effec-
tive immediately. The supplemental labels have been
distributed to all local retail outlets and are also avail-
able directly from your local Syngenta representative.
Syngenta Crop Protection, Inc.
P-0. Box 18300
Greensboro, NC 27419-8300
RESTRICTED USE PESTICIDE
TOXIC TO FISH, MAMMALS, AND AQUATIC ORGANISMS
FOR RETAIL SALE TO AND USE ONLY BY CERTIFIED APPLICATORS OR PERSONS
UNDER THEIR DIRECT SUPERVISION, AND ONLY FOR THOSE USES COVERED BY THE
CERTIFIED APPLICATOR'S CERTIFICATION.
Agri-Mek@ 0.15 EC Miticide/lnsecticide
EPA Reg. No. 100-898
SUPPLEMENTAL DIRECTIONS FOR USE for:
* Revised Spray Drift Directions
* Addition of Aerial Application to the Citrus Fruit Crop Group
* Addition of Pests to Fruiting Vegetables Crop Group, Grapes, and Potatoes
Abamectin ...................... ................................ .......................2.0%
Other Ingredients: 98.0%
'CAS No. 65195-56-4 and No. 65195-55-3
*1 gal. contains D.15 Ib. abanectin
KEEP OUT OF REACH OF CHILDREN,
Si usted no entiende la etiqueta, busque a alguien para que se la explique a usted en detalle.
(If you do not understand the label, find someone to explain it to you in detail.)
SCP 898A-S8 1208