GENERAL PRACTICE. DISEASES. H7 



the winter. How, then, can mildew appear in the following year ? Another set of 

 growths forms on the spawn threads. Each is a slightly flattened sphere, black and 

 furnished with radiating brown tentacles, with an inconceivably thin outer coat 

 (wall) formed of cells, surrounding small transparent bladders (asci), each of which 

 encloses two, four, or eight spores. These are known as " fruits," the outer coat enclosing 

 them being proof against drought, frost, and water. During winter they remain intact, 

 but when early summer produces "genial warmth and soft glow of moisture," the outer 

 coat of the mildew " fruit " is so acted on that it cracks, and the bladders burst forth, rise 

 and sail through the air, but soon split open and scatter the spores. These falling on the 

 blossoms or tender growths of fruit trees, germinate at once, weave a web of mycelium, 

 and cause the immediate production of mildew, or Oidium in the club form. 



With a knowledge of the habits of mildew a clue to possible prevention or cure 

 becomes tangible, but without such information attempts to ward off the disease are 

 empirical. Various conditions of tree growth favour fungoid development, and these 

 are produced by certain climatic and cultural agencies. Eain following a dry period 

 cleanses mildew-afflicted fruits, leaves, and shoots simply through washing off the spores, 

 and mildew is rarely seen on well-syringed peach and other fruit trees grown under 

 glass. Ventilating fruit-houses in spring and early summer by opening only the upper 

 sashes in spells of cold, dry, " sharp " weather, or admitting air by the front or side 

 ventilators whilst keeping the top lights closed on account of unfavouring wind direction, 

 insures immunity from mildew simply because the rush of air is outwards and drives 

 away its spores. Thus the late Mr. Thos. Eivers, by the fixed roof system of his orchard 

 houses and practice of ventilating only on the calm side in cold, dry weather, excluded 

 Oidium. But when the early day ventilation of fruit-houses is neglected in bright, yet 

 cold weather, and the bottom as well as the top ventilators are thrown open, the external 

 air rushes in and with it the Oidium germs. Thus chills are said to produce mildew, 

 but it is always a question of spores. 



Cleanliness and careful culture are the antidotes for mildew. Therefore, all fallen 

 leaves, as well as the prunings, of mildew-infected trees should be collected and burnt, 

 the trees washed with a fungicide, and the ground about them pointed over. If under 

 glass, syringe every part of the house and trees with water at 140 to 160, thoroughly 

 cleanse the woodwork with soapy water and brush, whitewash the walls, and wash the 

 trees with a solution of soft soap, 3 or 4 ounces to a gallon of water, using a brush, taking 

 care not to injure or dislocate the buds. Clear away the surface soil, appiy a suitable 



