TULIP BOTRYTIS BLIGHT (Botrytis tulipae),
tulip fire, a general problem. Plants from infected bulbs are often stunted, with buds blasted; leaves sometimes have large light patches resembling frost injury (Figure 13B). When gray mold forms on affected parts, spores are splashed by rain to nearby tulips, causing myriads of small white spots on colored petals, brown spots on white flowers. In another day or two such a flower is covered with its own mold, ready to infect more and more tulips. Small black sclerotia are formed in leaves and petals as they rot into the ground, and also on bulbs.

Control. Practice strict sanitation. Inspect bulbs before planting; discard those showing sclerotia. When a whole plant is blighted in spring, dig out immediately. Cut fading flowers into a paper bag instead of letting petals rot on ground. Cut foliage at ground level as soon as it ripens and turns yellow. Spraying weekly, before blooming, with Fermate or Zerlate v somewhat helpful. If this disease has been present for some years in your garden, plant new healthy bulbs in a different location.

CELERY BLIGHTS.
Early blight (Cercospora apit) is characterized by small yellow leaf spots which change to large irregular ash-gray regions. The spores are splashed by rain or carried on tools or gardener's trousers through the patch. In late blight (Septoria apii and 5. apii-graveolentis) the spots on leaves and stalks are covered with small black dots, fruiting bodies of the fungus.

Control. Unless seed is 2 years old, tie in cheesecloth and treat with calomel. Spray or dust with Dithane Z-78, Parzate, Zerlate, or with a fixed copper, starting in the seedbed. Rotate crops; clean up all refuse at end of season.

FIRE BLIGHT (Erwinia amylovord).
This is a serious bacterial disease of pear, quince, apple, and related species, including hawthorn, mountain-ash, pyracantha, and cotoneaster. Many pear orchards have been wiped out. Blossoms and leaves of infected twigs suddenly turn dark brown to black, shrivel and die, but remain attached to twigs. Blighted branches thus appear to have been scorched by fire.

The bacteria survive the winter in holdover cankers on the limbs. These are slightly sunken areas with a definite margin at the base of branches. In spring, drops of bacterial ooze appear, to be carried by rain and insects to blossoms, leaves, and fruit.