CUCUMBER DISEASES. The cucumber is subject to the attack of a number of fungi. only the more important of which can lie mentioned. In the seed-bed it is liable to the attack of Pythitun deharyanum, the disease being milled `damping oft' (q.v.). In the field one of the worst pests is Plasnmpara, or Feronospora •u bensis, producing mildew. It attacks the foli age, causing the leaves to turn yellow, to wilt, and die, the whole vine being involved. Spray ing with some fungicide (q.v.). as Bordeaux mixture or potassium sulphide, will prevent this disease if applied early and often. Care must be taken to spray the mixture upon the under sides of the leaves. In addition to encumbers, this mildew occurs on muskmelons, squashes, and pumpkins. Another fungus, Cladosporium en eumerinum, attacks the fruit of the cucumber and melons, producing upon the young fruits small, sunken areas that later become black, rot ten places. Often a sort of gummy exudation is associated with this disease. The treatment given above is recommended for this disease.
In the greenhouse the most serious trouble to cucumber-forcing is the powdery mildew (Ery siphc cichoraccarum ). It may be known by the white, flour-like splashes on the leaves. The leaves become yellow, then brown, and dry up, killing the plant. The disease spreads with great rapidity, but may be kept under control as in the above cases. A disease known as the wilt disease is often of great destruction to cucumbers, melons, etc. It is caused by a kind of bacteria to which the name Bacillus trachei philus has been given. The organisms till the water-ducts of the plant. causing it suddenly to collapse. The leaf-blades shrivel and dry up, and later the petioles and stem become flaccid and the whole plant perishes. If a stem be cut across, a sticky, milk-white substance exudes. The disease is readily produced by inoculation, and is largely spread through the agency of in sects. A somewhat similar disease is caused by a species of Fusarium, a fungus.