DATE:   9/16/99                   
WRITER: Dr. Anthony P. Keinath, (843) 766-3761
EDITOR: Giles Singleton, (864) 656-3876
 
Controlling Diseases on Fall-Planted Greens
 
     CLEMSON -- Disease control on fall-planted collards and
greens can be difficult if control measures are not started early
in the season. The moderate temperatures and regular rainfall in
fall create conditions that favor leaf, root, and stem diseases.
In addition, greens are often planted densely, so leaf surfaces
remain wet when plants are close to mature.
     Collards and greens that have been planted in an area
rotated away from other cole crops like cabbage and broccoli will
develop disease later than those planted season after season in
the same area. 
     Perennial weeds can carry some diseases, such as black rot
and cucumber mosaic virus, so weed control around the garden is
important.
     Another disease, wirestem, which occurs on transplants, is
caused by a fungus in the soil. Stems of seedling affected with
wirestem become constricted and brittle. It is less severe on
collards or kale planted late (after Sep. 15, Oct. 1, and Oct. 15
in the Piedmont, Midlands, and Coastal areas, respectively),
after soils are cooler.
     Black rot can be carried on cole crop seed, especially 
collard seed. Symptoms of black rot include yellowing of leaves 
and blackening of veins. Gardeners who use plant beds to start
transplants should apply copper hydroxide to seedlings at half
the labeled rate several days before transplanting. This will
prevent the spread of black rot during transplanting. 
     Spray the copper hydroxide during the early morning to avoid
burning young plants during hot weather. Collard and kale are
more susceptible to black rot than mustard and turnip. 
     Symptoms of leaf spots usually will first be seen on the
older leaves. These leaves can be removed to slow spread of
disease to neighboring plants or younger leaves. 
     As plants grow, they should be thinned so that leaves of
neighboring plants do not overlap. If disease is so bad that
leaves fall to the ground, these should be removed from the
garden before tilling the soil.
     Copper hydroxide and copper plus sulfur are the only
fungicides labeled on greens for the home garden. Because these
two fungicides are only partially effective, they must be applied
before any disease symptoms are seen. A general rule of thumb
would be to start copper sprays two weeks after transplanting or
three weeks after emergence of direct-seeded crops.
     Please remember, there is a one-day waiting period between
spraying copper and  harvesting. --  Anthony P. Keinath,
Extension vegetable pathologist.
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     If you have questions or comments on gardening-related
issues, write to PSA News & Publications, Box 340129, A-101 Poole
Agricultural Center, Clemson University, Clemson, S.C. 29634-0129. 
     You might also want to look for other "Buds and Blooms"
columns under 1999 News Releases at: www.clemson.edu/agcomm . 
     Also check out Clemson Extension's new Home and Garden
Information Center (HGIC) at: http://hgic@clemson.edu or 
1-888-656-9988. HGIC has information specialists on call from 
9 a.m. to 1 p.m. Monday through Friday for information not covered 
by the recorded messages and fact sheets.
                              END