Greenhouse - Celery
( Originally Published 1920 )
Cultural Considerations. Celery has not yet taken its place among the standard forced vegetables. It is possible, however, to produce celery in the greenhouse which is of a quality far superior to that grown out of doors. The self-bleaching varieties such as the Kalamazoo seem to be well adapted for forcing. The White Plume seems to have a tendency to go to seed, and the Golden Self-blanching is subject to heart rot, Celery requires an abundance of moisture. A lack of it will cause such a setback to the plants that they may never recover. Too high or too low a temperature has the same detrimental effect.
DISEASES OF THE CELERY
Celery is subject to numerous diseases. Success with the crop demands great care in the production of healthy plants.
SOFT ROT, see Cauliflower, p. 126.
Caused by Septoria petroselini Desm. var. apii Br. and Cav.
Symptoms. The disease first attacks, the lower leaves of the stalk, producing irregular spots with-out a definite boundary line. When the spots be-come numerous the foliage withers and dries up (fig. 8, a.). The disease attacks the leaves as well as the stalks, rendering the affected plants useless for the market. In storage, plants affected with late blight will keep very poorly or rot altogether.
The Organism. The fungus mycelium is hyaline, septate. The pycnidia (fig. i8, b.) are olivaceous, prominent, and abundant in the spots. The pycniospores are filiform, straight or curved, hyaline and many are septate (fig. 18, c.).
Control. According to Rogers,* late blight may be controlled by spraying with 5-6-50 Bordeaux.
The first two applications should be given to the seedlings in the seed bed. In the house the first spraying should be administered about six weeks after transplanting. Besides spraying, shading also seems to keep the disease in check. In spraying celery, great care should be exercised to apply a fine mist. Where this is overlooked, large drops of the Bordeaux mixture may be deposited on the leaves and stalks, which upon drying may deposit copper salt in sufficient quantity to injure the consumer. Sprayed celery should be carefully washed and dried before shipping.
Caused by Cercospora apii Fr.
Symptoms. The trouble first appears on the outer leaves as pale blotches visible on both sides of the affected parts. The spots are irregular, angular in outline, limited apparently by the leaf veins, with slightly raised borders (fig. 19, a.). The spots later turn brown to ashy white.
The Organism. The conidiophores are usually borne on the under side of the leaf, light brown, and in clusters. The conidia are hyaline, 3 to I0 septate, cylindric.
Control. Early blight as well as late blight may be controlled by spraying with Bordeaux mixture. The Boston Market and Golden Heart varieties should be avoided because of their susceptibility to the disease. The White Plume seems to be resistant.