Types of Garden Enemies
This is called drop in lettuce; older leaves wilt and lie flat on the ground while the center is reduced to a slimy wet mass. In celery it is called pink rot; in beans, carrots, crucifers, and cucurbits the disease is known as cottony rot. In all cases the sclerotia drop to the ground and in spring produce rather large apothecia, up to an inch across, which eject spores in a veritable cloud. There is no conidial stage.

Control. Commercial growers often have to flood the soil or to treat it with calcium cyanamid to kill sclerotia. In home gardens peonies and other plants whose stalks or flower heads are invaded should be cut and burned immediately, making sure that the slerotia do not fall out through breaks in the stem before the specimen is safely in a paper bag.

This relatively new and most destructive strawberry disease destroys fine feeding roots first, then invades the stele which turns dark red. New leaves are small, blue in color; leaves from the previous season dry up; little or no fruit is produced; many plants die.

Control. Resistant varieties provide the most feasible control. Use Aberdeen, Pathfinder, Sparkle, Temple, or Fairland. Dithane as a ground treatment has helped.

There are a number of common turf diseases that are rather difficult to classify. They are as near rots as anything else.

BROWN PATCH (Pellicularia filamentosa).
Roughly circular, wilted brown areas appear in lawns, from a few inches to 3 feet across, rarely to 20 feet. The leaves are first water-soaked, then light brown, dry. Infection comes from very small, dark-brown sclerotia on the soil surface, in warm, humid weather. Watering late in the day encourages the disease and so does an excess of nitrogen in the soil. Mercury compounds- calomel and bichloride of mercury (Calo-clor), phenyl mercury acetate (PMAS)-apparently give best control.

DOLLAR SPOT (Sclerotinia homeocarpa).
The lawn spots are small, about 2 inches across, first brown, then straw-colored, but they may grow together to make larger patches. You can usually see a fine cobwebb mycelial growth in early morning when dew is on the grass. Cadmium fungicides are preferred for dollar spot and also for copper spot which causes coppery orange patches, i to 3 inches across, more often on velvet bent grass in acid soil.

SNOW MOLD (Typhula spp.)
This is a scald that takes place as snow is melting, resulting in conspicuous white circles in lawns, 1 to 3 feet across, due to another sclerotial fungus that lives over in the soil. Mercury compounds as for brown patch are recommended, but in my experience grass returns to normal color later in the season without treatment.

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