Foreign plant quarantines in-service training series


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14 Ceroospora mrasae

United States Department of Agriculture
Bureau of Entomology and Plant quarantine
April 1, 1940
Foreign Plant Quarantines In-service Training Series. No. 3
(No. 1 is an introductory and explanatory number.)
Prepared by N. Rex Hunt

Name of diseases Banana leaf spot, Sigatoka (The Sigatoka district
of Fiji was one of the first in which the disease
caused severe damage.)

Name of Pathogens Cercospora musae Zimm.

Hosts: Musa sapientum, M. paradisiaca, M. fehi, M. cavendishii. M.
paradisiaca var. lacatan is quite susceptible but var. dacca
(Red Dacca) is resistant.

Part attacked: Leaves.

Plaoe oforigini Java, so far as known.

Place of first report: Java, 1902

First report from U. S.t Puerto Rico, 1938.

Present distribution: Australia, Caribbean region including Central
and South America and West Indies, Mexico,
Ceylon, Fiji, Java. Tanganyika, Uganda

Factors affecting severity: Precipitation and humidity, temperature,
air currents are involved but conflicting reports make it
difficult to determine the particular combination of factors
making disease especially severe in some areas and not in
others. Probably the amount of inoculum available and time
of distribution of spores as well as temperature, moisture,
and host condition are important.

Methods of spread: Air currents doubtless account for most local
spread and might account for spread for considerable
distances. Leaves or fragments may sporulate for a time and
these or spores adhering to comrrLercial shipments may account
for trans-ocean spread.

Losses incurred Little definite data on losses from the disease are
available. It is reported that it caused a loss of 60 of
the total crop in Fiji in 1932, the loss at the Experiment
Station being 100% (1h). Some investigators indicate that
serious losses in transit as well as reduction in quality of
the fruit is associated with this disease (L, 14).


Comparison of losses: Losses are usually stated in general terms and
are not readily comparable. They vary from negligible to total,
depending on country, locality, weather conditions, host
varieties. Not important in Java and Ceylon apparently but
frequently destructive in Fiji (7), Australia (4, 9) and the
Caribbean region (5, 6, 10, 11, T2, 13), especially in Central
America. Gros Michel, the most important variety in commercial
plantings in Central America, is very susceptible, as is the
Cavendish type.

Control methods: Spraying or dusting is used for valuable commercial
plantings. Bordeaux 5-5-50 seems to be more or less standard
as a treatment and is applied as many as 18 times per year.
Sanitation is recommended also. In some plantations a
permanent system of pipes is installed to carry spray under
pressure from a central plant. Other places the land is steep
or otherwise unsuitable for the use of spraying equipment and
dusting must be used. (1, 2, 4, 6, 10, 12)

Quarantine action: No quarantine action based on this disease has
been taken but the banana plant quarantine, No. 31, dated
March 15, 1918 and effective April 1, 1918, forbids the
importation of banana plants or parts thereof, other than the
fruit. Under this quarantine the removal of banana leaf parts
and other debris has been carried out at various ports where
banana shipments arrive.
An investigation of the status of leaf spot in the
Caribbean region and of the banana imports of Puerto Rico was
started to assemble data for use in determining whether or not
further restrictions were needed for the protection of Puerto
Rico but the disease was soon found to be present several places
in Puerto Rico. Bananas and banana relatives are more or less
important landscape material in Florida, but it was not felt
that any special restrictions to protect them would be required.
Hawaiian authorities felt that they were fully protected by
quarantine measures already in force.

Description The first symptoms to appear on infected leaves are
minute yellow green speckles which later become yellow green
streaks parallel to the veins. When mature the streaks turn
brown and a broad black margin is formed by impregnation of the
tissue with a dark red or black gum. Most spots turn brown
within a week after reaching full size. Mature spots are
usually only a few mm. long. Sporulation may start when this
brown stage is reached. Some spots widen and in their last
stage have a gray center, with scattered black dots from old
fructifications. Usually it is a month from the time of
infection to the first sporulation.


Old leaves are not readily infected. Infection usually
takes place as the leaves are unfolding, but the lesions do
not show until the next pair of leaves has had time to open.
The spores of Cercospora musae are variable in size, shape,
and number of septa. They are usually 5-4 x 4O-60 mu fith 2
to 4 septa. The basal end cell or two cells may show a
tendency to be fusiform. Smane spores are only one or two
celled and nearly oblong instead of tapering or slightly curved.
Spores may remain viable for several weeks.
WThile a species of mycosphaerella found on leaves infected
with C. musae is suspected to be its perfect stage, the
connection has not been fully established as yet. The
Mycosphaerella perithecia contain one or two asci 24-28 x
10-12 mu and -celled hyaline spores 20-22 x 5-6 mu. Spores
slightly constricted. (15)
Infection with C. musae seems to require three or four
successive nights of high humidity with temperatures not above
800 F. Heavy dews or light drizzling rains are more conducive
to infection than heavy rains. Heavy rains probably tend to
wash the spores to the ground. Intermittent dews or rains may
cause spores to germinate but in order for any large number of
hyphae to enter the leaf and establish themselves a minimum
period of three or four days of moisture seems to be required.
If such periods occur only while few spores are present on the
leaves, little damage results. However, in many places
infection is most likely to occur along the midrib as the leaf
is opening and to occur in numbers. Each spot cuts off all
the leaf surface from there to the margin of the leaf if there
are many spots infected and severe leaf injury may follow
infection in spots whose total area is less than 10& of the
leaf area.
We find statements that the disease is severe only on
bananas being grown under unfavorable conditions, that the
disease is much worse on bananas making rapid growth or Cron
on the best land, that much moisture is required to permit
development in serious proportions, that the disease spreads
rapidly even in dry areas, that good aeration should reduce
incidence of disease, that increased aeration has increased the
disease, and similar apparently incompatible statements. One
correspondent believes that much of the injury attributed to
C. musae in the region he visited is in reality due to other
causes. Since many of the spots due to C. musae do not sporulate
and other fungi, both parasitic and secondary, are likely to be
present on the leaves and various types of insect injury
complicate any analysis of the effects of C. musae, any accurate
picture of the effects of this disease cannot we'l be made
without careful data from diverse areas assembled over a period
of years. (1, 5, -8, 9, 10, 11, 12, 153, 15., 16, 17)


Bibliographys Only a few of the articles consulted are listed.
Considerable information was received in the form
of correspondence.

(1) Barnes, A. C.
1937 Leaf spot disease of bananas. Journ. Jamaica Agrio. Soo.
41, 603-7. 1937.
Most affected plants recovered. Disease apparently will be
confined to areas where conditions for cultivation are not
wholly favorable. Infection present all over island, probably
has been present in a mild form for a long time.
The cost of each application of copper sulphate and lime
dust is about 2 shillings per acre.

(2) British West Indies Fruit and Vegetable Council.
1938 Report of the First Joint Meeting of the Eastern and
Western Group Councils and of the Third Meeting of the Eastern
Group Council held at the Imperial College of Tropical
Agriculture, Trinidad, February, 1938. 61 pp* Gov't Print.
Off., Port-of-Spain, Trinidad, 1938.
(Abstr. in R.A.M. 171 610-11. Sept. 1938)
Discussion of*C. musae on pp. 12, 13 by F.3.V. Smith of
Jamaica and C.W. lardlawof Trinidad. E.3. Cheessman of Trinidad
discussed possible new vars. of banana.
(Spraying with Bdx. regularly said to cost $15 or more per
acre annually.)

(3) Cheesman, E. E. and Wardlaw, C. W.
1937 Specific and varietal susceptibility of bananas to Ceroospora
leaf spot. Trop. Agric., Trinidad. I4 335-336. 1937.
Wild banana species are usually resistant and most hybrids
bred from them are resistant also. One hybrid (Gros Michel x
Musa acuminata) shows promise of being a commercial variety, only
the oldest leaf showing spotting.

(4) Dickson, B. T.
1928 Leaf Spot of Banana in Southern Queensland. Queensland
Agrio. Journ. 30: 455-457. 1928.
Leaf spot is prevalent on many banana plantations, in most
cases causing serious loss both in number of bunches produced
and in size and quality of fruit. Use of windbreaks between
plantations is recommended.

(5) Dunlap, V. C.
1938 In a letter dated Spt. 12, 1938, and addressed to B. R.
(Mr. Dunlap has seen the disease in various countries and at
different stages,) While original spread seems slow the amount


of infection gradually accumulates and usually in one or two
years plants suddenly become so badly defoliated that fruit
is badly damaged. Eyen in the driest producing areas spread
of the disease appears to be rapid. Occurrence of especially
virulent strains is doubted.

(6) Ferrer, R. B.
1958 El control de la 'Sigatoka' del Banano. Bol. Coop. Banan.
Magdalena Lim., Colombia, 1938, 7-8 pp. 7-19, 14 figs., 1938.
(Abstr. (brief note) in R.A.M. 18:124, Feb. 1939)
Discussion of economic, technical and practical aspects of
control of Sigatoka in Mexico, Honduras, Guatemala, and
Colombia. Spraying 5-5-50 Bordeaux or 20-80 copper-lime dust
is recorriended.

(7) Parham, B. E. V.
1954 Annual Report on Banana Disease Investigations, 1933. 16
pp. (Fiji.)
Cercospora musae has been the most virulent banana disease
in Fiji during the past 20 years. The disease is now widely
distributed. In 1932 about fQ% of the fruit destined for
export was rejected at the packing plants because of the effects
of this disease.

(8) Simmonds, J. H.
1933 Panana Leaf Spot. Dept. Agric. & Stock, Div. of Entom. &
Plant Path. Queensland. Pamphlet No. 6, pp. 5-22. Jan., 1933.
Dusting and stripping as tried were ineffective.
Spore measurements given by Zimnerman for Java, 60-80 x 4
mu; Massee for Fiji, 60-75 x 4-4.5 mu; Campbell for Fiji,
25-66 x 2-5 mu; Campbell for Queensland, 20-80 x 2-6 mu;
Sim-nonds for Queensland, 21-80 x 3-6 mu; Sinnonds for Malaya,
L40-81 x 2.5-3.5 mu.
A table shows the percentage of germination obtained with
spores kept different lengths of time. Sixty-four percent of
the spores kept 8 weeks (Aug. 8 to Oct. 5) germinated.

(9) Simmonds, J. He
1955 Cercospora musae on Musa sp. Queensland Agr. Journ. 43:
254-267 1935.
Leaf spot and speckle are discussed. The spots caused by
Cercospora musae are described as being narrow, oblong, or
elliptical, brown to black, about a half inch long and an eighth
wide. VWhen older the spot dries out leaving a characteristic
grey spot bordered with a black line and surrounded by a yellow
halo. Grey spots are usually noticeable after the leaf dries
out. Minute greyish tufts of spores can sometimes been seen on
the surface of the spots following prolonged rainy weather.


The disease is usually present throughout the year. Three
or more days of continuous rain during moderately warm days of
February, March, and April cause an epidemic outbreak.
Defoliation in worst when growth is slowest.

(10) Smart, H. P.
1936 SiGatoka Leaf Disease of Banana. British Honduras Dept.
Agr. Leaflet 31 1-7. 1936.
Symptoms are given in detail for various stages. Spread
of the disease continued during the dry season of 1936 and was
greatest in the more fertile areas. Increased aeration of
plantings seemed to increase incidence of the disease. Spread
rapid but erratic*
Laboratory tests indicated that most spores are killed by
drying in 7 days*
Spraying every 10 to 14 days gives best results# Spraying
every week does not inoreare production enough to warrant added
expense. Hydrochloric acid solution is used (*) to remove
spray residue from the fruit.

(11) Smart, H. P.
1938 Report on Sigatoka Leaf Disease in British Honduras. (A
one page circular, Belize, British Honduras, Jan. 27, 1938.)
Sigatoka was first reported in British Honduras in 1936 but
did not make rapid headway until the following year when
production was considerably reduced on a number of plantations.
The disease was fcvnd in all the banana areas, in some places
only along the roadside or the railway. "It is most noticeable,
and particularly up the Belize River, that plants which show
greatest and severest infection are those which also show the
most rapid and lush growth."

(12) Smith, F. E. V.
1937 Leaf spot disease of bananas. Journ. Jamaica Agr. Soo. 14,11
603-607. D. 1937. No. 12. Report of address of Director of
Agriculture, Dec. 1, 1937.
Believes disease will be virtually confined to areas where
conditions are not entirely favorable to banana culture although
distributed all over the island. A yoar round spray program is
advocated. Diseased material should be buried as spores are
distributed by air currents induced by burning.

(13) Stahel, Gerold
1937 Notes on Ceroospora Leaf Spot of Bananas (Cercospora musae).
Trop. Agrio., Trinidad, 141 257-264. Sept. 1937-
This is a detailed account of the disease with good
illustrations of the spots on leaves and of drawings of stages
of the fungus. The Mycosphaerella associated with 0. muuae is
described informally and is to be named M. minima. -Infection


was found to take place on lower leaf surfaces only. Spore
germination was found to start within a day or so in moist
air, the short flat germ tube growing slowly and becoming
attached to the leaf surface. In 4 to 6 days stomatopodia
appeared above stimatal pores on the lower surface of leaves.
T .e pore was then invaded and the protoplasm from the germ
tube was then drawn into the stoma. Thus it takes 5 to 7 days
for the fungus to get inside the leaf. Later mycelium grows
out through stanatal pores on the lower surface of the leaf
and spreads over the leaf to some extent. The 20 days or so
during which the myoelium is active in the living leaf tissue
it is considered parasitic. Death of the affected leaf tissue
occurs within a few hours after the mycelium grows out over
the surface. The fungus then invades the dead tissue from the
outside and forms Cercospora fructifications on both surfaces
of the leaf. Fructification on the lower surface takes place
during the 20 day period of parasitism also.
The conidia pictured are from less than 60 to about 95 mu
x 3-5 mu and with 4 to 6 septa.

(14) Surridge, H. R.
1933 Ann. Rept. Agric. Officer, 1932. Dept. Agri. Fiji, Ann.
Bull. Div. Repts. 1932. 19533.
Cercospora musae devastated old and young plantations
throughout the year causing a loss of 60% of the total banana
crop. At the Experiment Station the loss was 100%. Apart from
destruction of plants and reduction of yield, the disease seems
involved in premature ripening of fruit and breakdown in

(15) Ward, F. S.
1958 Cercospora leaf spot of bananas. Journ. Jamaica Agric.
Soc. L2: 25-3h. 1958. also published as Bull. 15, Dep. Sci.
Agric. Jamaica. (Abstr. in R.A.M. 17: 475-4-. 1938).
Disease bad on new land that produces poor bananas anyway.
Hot severe on first-class banana land. Spraying results

(16) Wardlaw, C. W.
1935 Diseases of the banana and of the Manila hemp. X + 615 pp.
2 col. pl., 280 figs. London.
Information regarding the banana leaf spot (Cercospora
musae) is found on pages 285, 286, 291, 292, 2953, 515.
'TAlthough it is usually possible to find some lesions
throughout the year, these are scanty during the summer months,
being mostly associated with old trash."

(17) Zimmerman, A.
1902 Uber Einige an Tropischen Kulturpflanzen Beobachtete Pilze,


II, Centralblatt fur Bact., II, Bd. VIII, p. 219, 1902.
(also Sacc. 18: 610-611)
Cercospora musae sp. n. On light brown, dark margined
leaf spots, most of them extended perpendicularly to the
principal vein. Conidiophores mostly on the upper surface
and seldom on the lower surface of the leaf, bursting forth
from the stomata, light gray brown. Conidia of the same
color, mostly somewhat curved, 5-6 celled, 60-80 mu long, 4
mu wide.
Rather frequently on leaves of Musa sapientum at
Buitenzorg, Java.

Fig. 1. Typical spots: above, from
late infection; middle, normal dry
centre spots; below, broad spots on
loaf of young plant.

Fig. 2. Infection No. 128; second leaf infected
22nd November; right, on the lower side; left,
on the upper side; first symptoms 10th December;
photographed 28th December.

(From Tropical Agriculture I4:. 257-264. 1957. Plate V.)

Digitized by the Internet Archive
in 2012 with funding from
University of Florida, George A. Smathers Libraries with support from LYRASIS and the Sloan Foundation unit

Cer0OOipor musas

Plate 2


Ceroospora musae.--1l Section through aoervulus on upper side of
dry center. 2 Stoma of recently killed spot with emerging
aoervulus. 3. Conidia. 4. Conidia and aoervulus section. 5*
Two oonidia that have germinated and formed stomatopodia (a) and
substomatal vesioles (b). 6. Stomatopodium (a) and substomatal
vesiole (b) in oroas-seotion of stomao 1, 2, 3, 5, and 6 after
Stahel in Tropioal Agriculture 14. 257-264. Plates I and II.
1937. 4 after Wardlaw, Diseases of the Banana and of the Manila
Hemp Plant, page 290. 1935.


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