ANNUAL MEETING AT LEXINGTON. 299 



and the applications should be made to the young wood. Prof. Burrill 

 suogest^ tirst pruning away the young wood, especially that most 

 affected, then syringing the tree with the dilute emulsion. This emul- 

 sion destroys the spores of the fungus, but does not injure^the tree. 

 Prof. Sanders, (Canadian Horticulturist) suggests the following reme- 

 dies : 



First — Hyposulphite of soda one pound, water ten gallons, ai)ply 

 with force pump just before the leaves appear, or when the fruit first 

 forms. 



iSeconfl— 'One pound of sulphur suspended in fifteen gallons of 

 water. Apply same as number one. Constant stirring is necessary to 

 keep the sulphur suspended. Lime water has also been used with suc- 

 cess. It should be ai)plied with syringe or force pump soon after the 

 young fruit forms and at intervals throughout the summer. 



The leaves of young apple trees are frequently attacked by a fun- 

 gus which covers the leaves with a dirty white coating. This fungus 

 grows upon the surface of the host and the plant body, consists of long- 

 branching cob-web-like threads, which attach themselves to the host 

 or supporting plant by means of suckers, which form on the side of the 

 thread next to the leaf. 



This fungus is known to botanists as Podosphwra tridactyla, and 

 it occurs on several plants belonging to the Rose family. It appears 

 about the middle of June, and soon the cob-web-like threads send up 

 number of vertical branches. They are at first entire, but ultimately 

 they are divided by several transverse partitions. Gradually the 

 threads become constricted at the partitions, until we ultimately have 

 formed a number of globular bodies arranged like beads on a string 

 (C. Fig. 3). The globular bodies are known as conidia, and whenever 

 the proper conditions of moisture and temperature are present the 

 conidia germinate and give rise to the same kind of cob-web-like threads 

 from which they were derived. These threads in turn produce another 

 crop of conidia which in turn germinate and produce threads. This 

 process continues through the summer months, until the parts of the 

 host attacked is covered with the cob-web-like threads. 



Late in the fall another kind of productive body is formed which 

 is commonly called the winter spore or resting spore. The conidia are 

 destroyed by frost, but the resting spores fall to the ground with the 

 leaf, live through the winter, and germinate the following spring. The 

 spores are contained in a flask. shaped sack called an ascus (C. Fig. 2), 

 and the ascus is protected by a thick wall, and which is usually colored 

 black or dark brown. The whole forms a more or less globular body 



