Drupaceous Fruits 85 



during the period of attack. The injury in the present year, 

 manifest by a loss in productiveness, is obvious to the grower. 

 The injury in succeeding years, often fully as great, is fre- 

 quently overlooked, or is not attributed to its true cause. 



It was formerly thought that this fungus persisted in the 

 twigs over winter, and thus lurked ready to infect the new 

 leaves as they began to develop. It has, however, been 

 proved that nearly, if not quite, all spring infection is due, 

 not to perennial mycelium, but to spores which remain on 

 the bark of the trees. 



Prevention of the disorder lies in killing these spores of 

 the fungus by winter spraying. For this purpose Bordeaux 

 mixture, Hme-sulfur, or a simple copper-sulfate solution 

 is efficient. There is probably little choice between these 

 solutions on the ground of efficiency; hence, the cost of the 

 various sprays may become the deciding factor. Lime- 

 sulfur is preferable when insects also are to ])e met. The 

 spray should be applied from one to three weeks before the 

 buds open in the spring, and thoroughness should be the 

 chief aim. Spraying should be done in dry, calm weather, 

 during the middle of the day, in order to avoid dew or frost 

 upon the limbs. 



Pierce states that as a result of the treatment of peach 

 curl in California, from 95 to 98 per cent of the spring 

 foliage was saved. A net gain of 600 per cent in the foliage 

 over that retained by adjoining unsprayed trees resulted 

 in the case of several different sprays. Bordeaux mixture, 

 when applied to the dormant tree, increased the weight and 

 starch-producing power of the leaves, and the sprayed trees 

 showed great gain over the unsprayed in the number and 

 quality of the fruit buds which they produced for the follow- 

 ing year. The gain in the numl)er of spur buds was over 

 100 per cent in some cases. The sprayed trees also produced 

 more vigorous growth of new wood, the wood to produce the 

 crop for the next year. Thus, in one experiment the spring 

 growth of the unsprayed tree averaged 7.85 inches; on the 

 sprayed trees it was 24.75 inches. The average value of 



