closes need protection from black spot disease
NEWARK, Del. - Black
spot disease is now making
its annual appearance on
roses which haven’t been
protected by spraying,
warns University of
Delaware Extension plant
pathologist Bob Mulrooney
This disease is one of the
most troublesome to afflict
roses grown m Delaware.
It’s caused by a fungus
which lives from year to
year on dead fallen leaves
and stems. Every Spring it
produces spores which infect
new foliage to start the
destructive cycle all over
again.
Symptoms of the disease
appear as nearly round
black spots on leaves of
untreated rose plants. Spots
vary in size but may get as
large as a half inch in
diameter. They have a
fringed border and several
may run together to form
large irregular black areas
on a single leaf. Usually
infected leaves will turn
yellow and drop
prematurely. This leaf loss
reduces the vigor of plants
and makes them more
subject to other diseases,
drought, insects, and winter
injury.
Sanitation is a very im
portant part of controlling
black spot, says Mulrooney
Cut canes of diseased plants
back as severely as possible,
and rake and destroy all
leaves at the end of the
growing season.
Rose varieties vary
greatly in their resistance.
Control is most effective if a
protective fungicide is ap
plied before the condition
appears or becomes
established. (See the end of
this article for recom
mended chemical controls
for both black spot and
powdery mildew.)
Powdery mildew is a
fungus which first appears
on young leaves as a
grayish-white, powdery
growth. Such leaves appear
to have been dusted with
talcum, and will become
twisted and deformed. The
disease later spreads to
older leaves as well.
DAVID H. HAGAN
Harkins & Carea Rd., Norrisville, MD
Just below Stewartstown, PA
301-692-6902
We Moved To A New Location.
IS NOW
SMUCKER'S SALES & SERVICE
RD #2, BOX 21
NEW HOLLAND, PA 17557
Proprietor - Amos S. Smucker
Location - IV2 mile East on Peters Rd. from previous location.
We Look Forward To Continued Sales & Service.
• Good used diesel • New Sputnik wheels
engines and parts
• We have another supply of Used Sputniks.
FOR PROMPT SERVICE CALL 717-354-4158
OR IF NO ANSWER, CALL 717-354-4374.
THANK YOU
SMUCKER'S
ENGINE SHOP
RD 1, GORDONVILLE, PA
17529
ELIS. SMUCKER, JR.
Lancaster Farming, Saturday, June 2,1979
When severe, powdery
mildew causes stunting and
distortion of leaves, stems
and buds. Buds may not open
at all, and tops of canes are
killed. The disease is usually
more severe on succulent
growth brought about by
excessive use of nitrogen
fertilizer, cautions the plant
pathologist. Control depends
on early, preventive
treatment. As m the case of
black spot, some rose
varieties are more resistant
to this disease than others.
To prevent black spot and
powdery mildew from at
tacking your roses, spray
plants with one of the
following combinations of
chemicals:
11/2 tablespoons of maneb
plus 1/2 teaspoon of dinocap
m a gallon of water; or
11/2 tablespoons of folpet
per gallon of water; or
1 1/2 tablesnoons of
NOTICE!
DISTRIBUTOR FOR:
LISTER, PERKINS &
SLANZI DIESELS
chlorothalonil plus 1/2
teaspoon of dinocap per
gallon of water.
Start spraying any of the
above combinations at bud
break and repeat at seven- to
10-day intervals until frost,
recommends Mulrooney.
It is also possible to treat
at 10- to 14-day intevals with
a combination of 1 1/2
teaspoons of benomyl in
combination with 1 1/2
tablespoons of either folpet,
chlorothalonil, or Fore (zinc
ion maneb) mixed in a gallon
of water.
For best results, shorten
the intervals between sprays
during rainy or humid
weather. Ideally sprays
should have been started in
mid-May, but your roses will
still benefit from treatment
if you start right now.
) have a
nice weekend...
For lower cost per
hour power, rely on
DIESEL POWER
13