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The Newsletter of
the Plant 2 '
Volume 3 Issue 9
Anthracnose: The Most Important Disease in Much
of the Mango-producing World
By Randy Ploet,
-i .!, r article by con-
S.r ind current stu-
11 ,!id on PLP News.
rn -!, md effort that
,_ d..l,.i quarterly FPS
y hat goes off to
I,.ci responsible for
ak rra i
asked me to write .
this article, he men-
tioned mango an-
thracnose and recent
encounters he had
had with the disease:
"A couple months
ago, a huge ship-
ment of Florida
mangos came in to Fifield '.1 1'l .1,!
for Dr. Bartz) and many were covered
in anthracnose just like the ones you
Ronald grew up in Peru where
most of the commercially produced
mangos are grown in low rainfall envi-
ronments that are not conducive to the
development of anthracnose. Thus, he
may not have seen much anthracnose
on mangos before this summer. High
summer rainfall in Florida provides
ideal conditions for this disease, and as
a consequence, mangos in the state
(especially from backyard trees like
mine that are not sprayed) are often
affected by at least some anthracnose.
Mango, Mangifera indica, is one the
world's most important and esteemed
fruits. Described by some as the "king
of all fruits," the mango is most
popular in Asia. It probably originated
in the Indo-Burma region, and
has been cultivated for at least
4,000 years on the Indian sub-
continent. It holds a prominent
place in Hindu mythology, relig-
ion, ritual, culture, ceremony and
FAO estimated that over
23 million metric tons (MT) of
mangos were produced in 1998,
about half of which were grown in
India. Mexico, however, is the world's
largest exporter of fresh fruit; it
shipped about 187,000 MT in 1997.
To put this in perspective, this figure is
almost 100 times higher than that for
Florida during the entire 1997 season.
During the summer after NAFTA was
enacted, more mangos were exported
into Florida from Mexico in one week
than were produced in the state during
that season. Mexican mangos have
little or no anthracnose since they are
produced on the arid Pacific coast of
that country. Thus, they are often es-
thetically superior to Florida mangos.
These factors, coupled with low pro-
duction costs in Mexico, have severely
crippled the Florida mango industry.
Ironically, many of the com-
mercial cultivars of mango that are
now produced worldwide originated in
Florida. Florida's role as a secondary
center of mango diversity resulted
from the early introduction to the state
of superior cultivars from India, most
notably Mulgoba in 1889. Mulgoba
and other introductions hybridized
freely, and some of the seedling prog-
eny from these trees were found to
produce better and more dependably
under Florida conditions than the
original parents. Haden, the first of
the important Florida cultivars, was
followed by many others including
Eldon, Glenn, Lippens, Osteen,
Springfels and Tommy Atkins. The
latter cultivar possesses moderate re-
sistance to anthracnose, is a reliable
bearer and is highly colored. Despite
its mediocre taste, Tommy Atkins is
currently the most important commer-
2 PLP NEWS
cially grown mango cultivar in the
Anthracnose is caused by,
Colletotrichum gloeosporoides (the fungus's
teleomorph, Glomerella cingulata, is ob-
served rarely on mango). Anthracnose
occurs in essentially all mango-
producing regions that have high rain-
fall. It affects leaves, stems and floral
panicles, but its most important dam-
age occurs on fruit. Typically, conidia
of the fungus initiate infection by pro-
ducing appressoria shortly after germi-
$j fection may
with the for-
nation of in-
from the base
of the appres-
S.soria and the
subsequent ramification of hyphae
throughout the epidermis; this usually
occurs, however, only after fruits have
begun to ripen. The reason that these
infections remain quiescent is not
known, but may be related to antifun-
gal compounds that are found in the
peel of mango fruits. Researchers in
Israel have shown that two com-
pounds, 5-12-cj--heptadecenyl resorci-
nol and 5-pentadecenyl resorcinol, oc-
cur in the peel at high concentrations
prior to ripening, and that the concen-
trations of these compounds decrease
dramatically once the ripening process
begins. Although there is compelling
evidence to suggest that the post-
harvest development of another mango
fruit disease, alternaria rot, is synchro-
nized with concentrations of the resor-
cinols and related to their effects on
the causal agent, Altenaria alternata,
similar work has not been conducted
Characterization of worldwide
populations of C. gloeosporoides indicates
that strains from mango comprise a
genetically and pathogenically distinct
population of this species. The mango
population of the pathogen always
predominated on mango, was not
found on other tropical fruit crops,
and had a restricted host range insofar
as individuals from the population
were highly virulent only on mango.
The genetic and geographic data were
used to suggest that the mango popu-
lation had been disseminated world-
wide from a single source, perhaps as
an endophyte in mango germplasm.
Chemical control of anthrac-
nose is difficult, especially in areas
Florida that experience heavy
Some fungicides that were
previously available, such as the
EBDCs, have been withdrawn from
registration by the EPA, and resistance
problems (benzimidazoles) or poor
efficacy (coppers) plague others that
are available. Among the new fungi-
cides that have been tested, the stro-
bilurins have demonstrated the greatest
potential for controlling the pre- and
post-harvest development of anthrac-
nose. Work is currently underway to
register these fungicides and devise
cost-effective management schemes
with them that will not result in the
development of resistance problems in
Variation in the susceptibility
of different mango cultivars to an-
thracnose is recognized, but more
than moderate resistance does not exist
in any of the commercial clones; in
high rainfall environments, all cultivars
must be treated with fungicides. To
date, classical breeding has not pro-
duced any anthracnose-resistant clones.
This is due, mainly, to: 1) the crop's
long juvenile phase; 2) its highly het-
erozygous nature; 3) the very low re-
tention of fruit in controlled crosses; 4)
the single, zygotic seed that each fruit
produces, and 5) the absence of par-
ents with high levels of resistance.
The recent collection of an anthrac-
nose-immune clone in Borneo, Mangaa
air, has led to the hope that it could be
used to breed an anthracnose-resistant
date, minimal progress has been
towards the biotechnological
provement of this crop.
In conclusion, I will make a
plug for Florida mangos (even those
that are covered with anthracnose!).
Mangos that are imported from over-
seas must be hot-water treated per
APHIS guidelines. Although this re-
duces post-harvest disease and insect
problems, it also "cooks" mangos and
reduces their organoleptic qualities.
Furthermore, anthracnose is a superfi-
cial disease. Since it progresses past
epidermal tissues only after fruits be-
come over-ripe, even fruits that are
severely affected taste
great after their peels
have been removed.
With apologies to the
Lite beer commercials,
I think most mango
connoisseurs, given the choice, would
choose a mango that tastes great,
rather than one that looks great.
Faculty, staff, students,
alumni, and colleagues of our
Announcing the 1st Annual
S' will be held
.K.1 J-. Octo-
; pared by
graduate students exhibiting their native
cuisine. This luncheon will benefit the
Plant Pathology Grad Student Associa-
tion. All faculty, staff, and students are
in July, as
3 PLP NEWS
part of an NSF-funded project on the
role of RNA editing in the restoration of
male fertility in sorghum. He also visited
collaborators in the Department of Bot-
any, Ulm University, Ulm, Germany, as a
guest of Dr. Axel Brennicke. He pre-
sented seminars on male sterility in sor-
ghum at both Universities.
Dr. James Kimbrough has just com-
pleted a book on "Common Mushrooms
of Florida" that will be published jointly
by the Cooperative Extension Service
and the University of Florida Press. The
book will contain keys, descriptions, and
color photos of 270 local mushroom
species. It should be available in early
Dr. Kimbrough presented the
keynote address to the 23rd Annual
Texas Mycological Society Meeting and
Foray at Huntsville, TX on Sept. 24-26,
1999. The topic of his address was
"Flesh Ascomycetes common to the
Southern States." In addition to this ad-
dress, he presented a seminar on
"The Twilight Years of W.A. Murrill at
the University of Florida." Dr. Murrill
described approximately 750 new species
from around Gainesville in the first half
of the 20th century.
Dr. Kimbrough has been asked
to participate in Archbold Biological Sta-
tion Fall 1999 Scientific Seminar Series.
He will present a seminar on Oct. 21,
1999 on "The Impact of Ultrastructural
Studies on the Systematics of the cup-
fungi and truffles."
On October 12, 1999, he will
present a seminar to the Ethnobotany
Club at the University of Florida entitled
"The Impact of Fungi on Human Af-
Dr. Kimbrough has been re-
cently invited to serve on a newly formed
"Faculty Proposal Review Committee"
established by the Office of Research,
Technology and Graduate Education.
This Committee will evaluate and select
the most competitive proposals for
Gabriela S. Wyss attended the last
SENVU (Senedo vulgarn) COST 816
Meeting. COST 816 is a European proj-
ect with the name Biological Control of
Weeds in Crops, lasting from 1994-2000.
Senedo vulgar is one of five weeds that
has been investigated in terms of possi-
bilities for biological weed control, be-
sides Chenopodium album, Calystegia seium,
Orobanche spp., and Amaranthus spp. This
working group SENVU met on a regu-
larly basis and this meeting was thelast
one. Therefore, everybody that contrib-
uted over the five years, (people from
Great Britain, the Netherlands and Swit-
zerland) summarized their research.
Gabriela, a post-doc working in
Dr. Charudattan's lab, gave an oral pres-
entation about Quantitative resistancein
the weed-pathosystem Senedo vulgars-
Puccnia lagenophorae. Control of Senedo
vulgars, common groundsel, in Europe is
followed by the so-called system man-
agement approach. The aim of this strat-
egy is to manage the target weed popula-
tion and to build-up epidemic on its by
the rust fungus Puccnia lagenophorae to
reduce competition between a crop and
the weed. It is not the aim to eradicate
the weed but to weaken the weed when
the critical period of the crop is starting.
Participants discussed what was
achieved during the research period,
what could have been done better and
then compiled the research necessary to
tell an audience if the system manage-
ment is able to follow with a certain
weed and fungus combination.
Dr. Bartz attended the Fresh Citrus
Juice Meeting at Lake Alfred last Aug.
30, 1999. This meeting was organized by
the Florida Citrus packers and the
Florida Gift Fruit Shippers Association.
YongXiang Zhang, from Dr. Jones' lab,
went to Colorado Springs from Aug 30
to Sept. 1st to set up experiments with
Shellie Huang and Tan Liu were mar-
ried on Sept. 13, 1999. Congratulations
and best wishes!
Camilla Yandoc passed her oral quali-
fying exam last Sept. 14.
Julianna Freitas-Astua passed her oral
qualifying exam last Sept. 16.
Coffee Break Schedule and
Birthdays for October 1999
Friday Coffee Break
10-1 Bartz and Berger
11-5 Kucharek, Kiml
10/4 Linda Farr
10/9 Matthew Pettersen
10/19 Susan Carlson
10/28 Jerry Minsavage
Cheng, WH, Taliercio, EW, and
Chourey, PS. 1999. Sugars modu-
late an unusual
T mode of control of
the cell-wall inver-
tase gene (Incwl)
through its 3 un-
translated region in
a cell suspension culture of maize.
Proceedings of the National Acad-
emy of Sciences of the United
States of America, 96(18): 10512-
Csizinszky, AA, Schuster, DJ, and Pol-
ston, JE 1999. Effect of ultraviolet-
reflective mulches on tomato yields
4 PLP NEWS
and on the silverleaf whitefly.
HortScience, 34(5): 911-914.
Duan, YP, Castaneda, A, Zhao, G, Er-
dos, G, and Gabriel, DW. 1999.
Expression of a single, host-
specific, bacterial pathogenicity gene
in plant cells elicits division, en-
largement, and cell death. Mo-
lecular Plant-Microbe Interactions,
Freitas-Astua, J, Rezende, JAM, and Ki-
tajima, EW. 1999. Incidence of or-
chid viruses in the State of Sio
Paulo, Brazil. Fitopatologia Bra-
sileira. 24:125-130. 1999.
Henny, RJ, Norman, DJ, and Kane, ME.
1999. Gibberellic acid-induced
flowering of Syngonium ,l/,yj ...'
Schott 'White Butterfly'.
HortScience, 34(4): 676-677.
Howad, W., Tang, H. V., Pring, D.
R., and Kempken, F. 1999. Nu-
clear genes from Tx CMS main-
tainer lines are unable to maintain
atp6 RNA editing in any anther cell-
type in the Sorghum bicolor A3
cytoplasm. Curr. Gen. 36:62-68.
Li, RH, Zettler, FW, Hiebert, E, Purci-
full, DE, and Morales, FJ. 1999.
Differentiation of dasheen mosaic
potyvirus isolates based on variabil-
ity in the apparent size of the capsid
protein in Western blots. Journal of
Ph -r. 1' rli..1.. -Phytopathologische
Zeitschrift, 147(6): 359-364.
Maffia, LA, and Berger, RD. 1999. Mod-
els of plant disease epidemics. II:
Gradients of bean rust. Journal
Norman, DJ, Chase, AR, Stall, RE, and
Jones, JB. 1999. Heterogeneity of
Xanthomonas campestris pv. hederae
strains from araliaceous hosts.
Phytopathology, 89(8): 646-652.
Norman, DJ, Henny, RJ, and Yuen, JMF.
1999. Resistance levels of pot an-
thurium cultivars to Xanthomonas
HortScience, 34(4): 721-722
Ploetz, RC, Haynes, JL, and Vazquez, A.
1999. Responses of new banana ac-
cessions in South Florida to Pan-
ama disease. Crop Protection, 18(7):
Satyanarayana, T, Gowda, S, Boyko, VP,
Albiach-Marti, MR, Mawassi, M,
Navas-Castillo, J, Karasev, AV,
Dolja, V, Hilf, ME, Lewandowski,
DJ, Moreno, P, Bar-Joseph, M,
Gamsey, SM, and Dawson,
WO. 1999. An engineered clostero-
virus RNA replicon and analysis of
heterologous terminal sequences for
replication. Proceedings of the Na-
tional Academy of Sciences of the
United States of America, 96(13):
Sinisterra, XH, Polston, JE, Abouzid,
AM, and Hiebert, E 1999. Tobacco
plants transformed with a modified
coat protein of tomato mottle be-
gomovirus show resistance to virus
Taliercio, EW, Kim, JY, Mahe, A, Shan-
ker, S, Choi, J, Cheng, WH, Prioul,
JL, and Chourey, PS. 1999. Isola-
tion, characterization and expres-
sion analyses of two cell wall in-
vertase genes in maize. Journal of
Plant Physiology, 155(2): 197-2114.
Leisure and Culture in
October '99 and Beyond
* "Asian Art from the Permanent Col-
lection" on display in the Ham Museum
through January 2000.
A d "Equal Partners" on
S display in the Ham Mu-
seum through November
* "Two Centuries of American Draw-
ings" on display in the Ham Museum
through November 28.
* "American Impressionism from the
Sheldon Memorial Art Gallery" on dis-
play in the Ham Museum through Janu-
ary 2. Call 392-9826.
* "EarthQuest; The Challenge Begins",
at the Florida Museum of Natural His-
tory. Thorugh January 30.
* "Children's Natural History Gallery", at
the Florida Museum of Natural History.
Through January 30. Call 846-2000.
I ,I i. 1i .i 1 1i
I P I ii, !'Id
Siii I gi:1 l
pizza and diniks!
Please plan to attend;
we will be discussing this year's field trips
October 16, Saturday, 9:00 am: Graduate
School Foreign language Exams
October 18, Monday, 4:00 pm: First
submission of Doctoral Dissertations
October 19, Tuesday, Midpoint of term
Last day to complete doctoral qualifying
exam if this term is to count as part of
the time that must elapse between the
exam and graduation
November 5-6, Friday-Saturday: Home-
All classes suspended. All offices closed.
Cool Web Sites
Check out www.careerpath.com. This site
offers searches of online job listings as
well as from 90 newspaper classified.
You can also post your resume for free!
Searching for Knowledge?
Try www.sccentral.com. This site is the
gateway to over 50,000 scientific sites
and news articles pertaining to over 120
specialties in science, medicine and engi-
neering. Includes searches, breaking news
Just web surfing?
Perhaps www.alienabduction.com can en-
tertain you. Thousands of people claim
to be abducted by extraterrestrials every
year-- find out who the aliens choose and
why they haven't chosen you!
5 PLP NEWS
E. P. DuCharme (1916-1999)
Ernest DuCharme, former plant pa-
thologist at the Citrus Research and
Education Center in Lake Alfred, passed
away in Winter Haven on September 7,
1999. Ernie was bor in St. Paul, Min-
nesota on July 15, 1916. He received his
B.S. degree in biology at St. Mary's Col-
lege in 1938 and his M.S. in Botany from
DePaul University in 1943. Subse-
quently, he went to the University of
Minnesota to begin work on his Ph.D. in
plant pathology. He completed his
course work and then joined the Florida
State Plant Board (now the Division of
Plant Industry). As an employee of the
Plant Board, he was sent to Argentina to
conduct research on the tristeza epidemic
that was killing citrus trees there. He
completed his doctoral dissertation there
and received his Ph.D. from the Univer-
sity of Minnesota in 1949. Ernie contin-
ued his research project in Argentina
In 1951, he joined the experi-
ment station at Lake Alfred as Associate
Professor, primarily to conduct research
on tree decline diseases. He was pro-
moted to Full Professor in 1956. His
most important contribution was the
discovery with Ross Suit that Radopholus
simii', the burrowing nematode, was the
cause of spreading decline of citrus.
Subsequently, these investigators helped
develop measures such as certification of
nursery stock and resistant rootstocks to
control the problem. He was also in-
volved in programs on citrus tristeza
virus and young tree decline (now citrus
blight). In the late 1970s, he began a
project on citrus canker in Argentina to
develop research information in order to
deal with the disease, should it be intro-
duced into Florida.
In 1974, Ernie was named As-
sistant Center Director of the experiment
station in Lake Alfred and served under
Herman Reitz in that capacity until his
retirement in 1981. After he retired,
Emrnie continued his interests in citrus
diseases and did some consulting in Ar-
gentina, Florida, and elsewhere. He also
enjoyed growing orchids and spent con-
siderable time with that hobby. Ernie
was fluent in French and Spanish and
enjoyed his travels to many countries.(L.
Special Request The Dover Re
search Center is searching for some is-
sues of Plant Disease that they are miss-
ing at the center. The following is a list
of the missing issues:
1997 May through November
1998 January, May, July
1999 January, March, May
If anyone has any of these issues
and would like to donate them to the
Dover Research Center, it would be
greatly appreciated. You can contact
Christine Manley via email at
cmanley(ufl.edu or by calling Christine
Manley at SunCom 512-1160.
Who is Who In Our Department
Who 1S ni..'
Dr. Robert (Bob) McGovem, currently
Bradenton, is originally from New York.
He obtained both his Master's and PhD
degrees from Comell University. For his
MSc., he worked on a non-characterized
disease in chrysanthemum; while his
doctoral project explored the interaction
between viroids and Erinia chysanthemi
and induced resistance. Before working
at UF, Dr. McGovem worked in the
flower industry for two years, where he
was the director of horticulture and diag-
nostics. Dr. McGovern has been working
at UF since 1990; initially, he was hired
at the research station in Immokalee to
run the Plant Diagnostic Clinic and to
work on vegetable and citrus diseases.
Then in 1995, he was transferred to
Bradenton to work on fungal soil borne
and foliar diseases of ornamentals and
occasionally on viral diseases. He consid-
ers himself a general plant pathologist. "
We have many projects going on right
now, but mainly we are working on a
Fusarium project, soil solarization for or-
namentals and vegetables, Colletoitchum
on several crops, recycling of pathogens
from run-off from irrigation of vegetable
fields, and low impact sustainable strate-
gies for the management of diseases."
Teresa Seija, has been the Senior Bio-
logical Scientist in the lab for three years.
She has a MSc. in Microbiology from
University of South Florida (USF); she is
in charge of overseeing all the laboratory
components and participating in field
research activities. Teresa brought the
molecular component to the lab, now
PCR and RFLP's are used in detection
Tim Davis, from Rockville, Maryland, is
the lab technician. He has a Bachelor's
degree in Biology from USF. Tim coor-
dinates most of the field activities. "Here
in our lab, 'contribution' is the key word,
everybody is pretty much involved in all
David Myers, Senior Agriculture Assis-
tant, the newest lab member is involved
in field research.
Monica Hoffine and Ezequiel Wil-
liams, OPS and students at New Col-
lege of USF, complete the whole crew of
Dr. McGovem's lab.
Dr. McGovem wanted to mention
Eddie Anderson, who worked in his
lab, recently returned to UF to pursue
the Doctor of Plant Medicine degree.
Did you know...
1.That Dr. McGovem plays the trumpet?
Once he played at a meeting in San
6 PLP NEWS
2. He also collects music, primarily jazz,
and also some Brazilian music and music
from around the world.
3. Teresa and Tim spend their spare time
with their little children. Teresa has a 2
year old little girl named Isabella and Tim
has a soon-to-be 2 year old son.
Greetings to all PI's at REC's! We
would like to hear from you! Do you
have any visiting scientists/scholars or
post-docs that we haven't heard about?
If so, we would like to feature them in
future issues of PLP News. Please send
us a short summary of where they are
from, their educational background, the
project they are working on, and personal
interests and/or hobbies. You can email
us at email@example.com. We
look forward to hearing from you!
If you would like to join our staff or con-
tribute an article, contact us!
1453 Fifield Hall
P.O. Box 110680
Gainesville, FL 32611-0680
Or, you can e-mail us at:
News Team September 1999
The opinions expressed in this newsletter are not
necessarily those of the PLPNews .