B. P. I.— 568. 



EXPERIMENTS ON THE APPLE WITH SOME NEW 

 AND LITTLE-KNOWN FUNGICIDES." 



INTRODUCTION. 



For many years Bordeaux mixture has been the leading fungicide 

 for summer treatment of the apple, the pear, and certain other fruits. 

 It was soon found, however, that it could not be used on the peach 

 and the Japanese plum, as it caused serious shot-holing of the leaves 

 and summer or premature defoliation of these trees. 



Injury caused by Bordeaux mixture has not been confined wholly 

 to the peach. There has been an increasing number of complaints 

 during the last few years about russeting or spray injury to the fruit 

 of the apple due to this mixture. Not only the fruit is injured, but 

 trouble has occurred on the foliage also, in the form of dead spots, 

 minute reddish flecks, yellowing, and, what is still more serious, defo- 

 liation. 



The fruit russeting has been pretty clearly recognized as due to 

 the spraying with copper. Minute reddish flecks on the fruit and 

 particularly the spotting and flecking of the foliage have been less 

 clearly attributed to copper poison, some pathologists and fruit grow- 

 ers understanding it, while others have mistaken the copper injury 

 for disease. While Bordeaux mixture has been the most useful 

 and successful fungicide that has ever been discovered, it has been 

 open to this serious objection, which for some unknown reason has 

 increased in recent years. 



«This paper is a preliminary report on some experiments on the apple with nine 

 different fungicides carried on in Virginia during the season of 1909. Among these, 

 an iron sulphid and a copper sulphid were sufficiently different from those previously 

 used to be regarded as new. The experiments were conducted in connection with a 

 study of the russet problem or spray injury to apples caused by Bordeaux mixture. If 

 the results can be relied upon they will help materially in solving this problem. While 

 the results with the new mixtures were favorable, the author very properly does not 

 recommend them for general use, but only for trial in an experimental way. The inter- 

 est in fungicides and in spraying fruit trees is so great and the demand on the part of 

 fruit growers for prompt information is so insistent that it seems desirable to give out 

 these results before they can be further tested. — G. H. Powell, Acting Chief of Bureau. 

 [Cir. 58] 3 



