Gainesville, Florida


Plant Pathology
Mimeograph Series No. 58-1


CONTROL OF THE COMMON DISEASES OF ROSES IN 1
H. N. Miller, Department of Plant Pathi
Florida Agricultural Experiment Statil


Description


Material


Formula


BLACK SPOT


POWDERY MILDEW


CERCOSPORA
LEAF SPOT


DIEBACK


Black spots and patches with
irregular or feathery margins
on leaves


Whitish irregular blotches
on leaves and twigs


Brown spots with gray centers,
regular margins,



Blackening of stems and dying
back from tip or pruning cut.
Sometimes wilting of shoots.


Captan (50%)
wettable


Ferbam (7-10%)
dust


Karathane
(25%) wettable


Sulfur dust
(325 mesh)

Maneb (70%)
wettable


1 oz/A gal;
4 tsp/gal


1 o//12-1/2
gal; 2tsp/
gal.


1 oz/4 gal.
6 tsp/gal.


Remove infected and fallen leaves.
Spray at weekly intervals, cover-
ing both leaf surfaces thoroughly.
More frequent applications may be
needed during the "rainy" season
when black spot is most troublesome, .
Dust every 3-5 days, during early
morning or late afternoon. Cover
thoroughly.

Spray at weekly intervals. Mildew
is not troubles me during summer
months. r

Sulfur may cause injury at tempe ra-
tures above 85 degrees F.

This disease is most serious on
poorly grown plants. Fungicides
only partially effective. Improve
growing conditions.


Remove by pruning,
low infected wood.
pruning compound.
conditions.


cutting well be-
Paint cut with
Improve growing


Disease


I




-2-


Disease Description Material Formula Remarks


CANKER


CROWN GALL


NEMATODES
(root knot)

(other species)


Localized diseased areas on
stem. Gray lesions with
reddish, regular margins or
indefinite light brown areas.

Somewhat rounded galls,
with rough, irregular sur-
faces on stems near ground
line, on roots, occasionally
on aerial parts.


Nodule-like swellings or
small galls are formed
on the fibrous roots.
Cause injury or loss of
feeder roots.


Methyl
bromide


D-D Mixtures


Ethylene
dibromide


1 lb.
25 sq. ft.


1/2 tsp. per
sq. ft. in
12 inch
spacings.

Available
in capsule
form for
garden use.


Same as DIEBACK. A regular spray
program for Black spot control will
keep these diseases in check.


Control by exclusion. Plant only
gall free new plants. Remove infected
plant dig out surrounding soil and
replace with new.
Fumigate areas known to be infested
before replanting.

No chemical treatment for use around
living plants is recommended by
Experiment Station at this time.
Keeping the bushes well mulched will
lessen the damage from nematodes.

The planting site should be fumigated
before plants are set, and only
nematode-free stock used.