DISEASES OF PLANTS. 433 



not be inserted, or an imperfect nnion of bud and stock, and (2) a 

 stunted development due to the annual early loss or dryiuij- up of the 

 leaves. Experiments conducted in 1889 and 18!)() showed that these 

 diseases could be prevented by the use of fungicides. Another series 

 of experiments was conducted at MuUiken, Maryland, beginning in 1S!)1 

 and ending in 1893. The treatment was to begin with the seedling 

 and end when the trees were of market:ible size. Incidentally, the 

 resistance of certain stocks was to be considered. The first year dif- 

 ferent stocks were budded at the same time and record keptof thednte 

 and number of applications, conditions of growth, and amount of 

 material and cost of spraying. The second year the growth of buds, 

 resistance, time, and amount of material needed to sj)ray the trees were 

 noted. The third year notes and measurements Avere taken and the 

 time and amount of material again noted; and finally the stock was 

 graded and photographed. The fungicides used were Bordeaux mix- 

 ture, ammoniacal copper carbonate, and ])otassium snlphid, the for- 

 mulas of which are given. Different numbers of sprayings were given 

 different plats, 5, G, and 7 applications being given the different plats 

 for the first 2 years. The third year the plats which had received 7 

 sprayings received G and the other 5 a[)plications. The more important 

 points brought out by the experiments are summarized by the author 

 as follows: 



"(1) The treatmeut had comparatively little effect on the apples; that is, tlie 

 nntreateil trees were, from the heji^inniiig to the end of the experiment, practically 

 as good as the treated. It must he borne in mind, however, that powdery mildew, 

 the ouly fungns that serionsly interferes with the growth of the apple in the nur- 

 sery, was almost entirely absent during the jirogress of the work. 



"(2) The most striking results of the work were seen in the case of the pears, 

 cherries, and plums, in the order named. 



"(3) Bordeaux mixture in every instance gave the best results, materially increas- 

 ing the growth of the pears and cherries, and never in any case injuring the foliage 

 in the slightest. iVs pointed our in other pul)lications of this divisioji, th(? remark- 

 able effect of this mixture can not be wholly accounted for on the ground of its effl- 

 cieucy as a lungicideor insecticide. It certainly possesses qualities aside from those 

 mentioned, and tiicse qualities, when well understood, it is believed ^\ ill jn'ove of 

 ccmsiderable practical im])ortance. 



"(4) There was no appreciable difference as regards growth between stocks treated 

 early and those treated late. In other words, withholding the application of the 

 fnngicide 10 to 15 days in spring did not materially affect the result so far as growth 

 was concerned. In some cases the plats sprayed 7 times seemed to be better than 

 those which received o sprayings, but the differences were so slight as to be hardly 

 worthy of notice. 



" (.5) As regards the effect of the stock on the bud, it may be said that- the experi- 

 ments showed nothing striking, excepting that the Japan pear roots in ahnost everj' 

 case gave the best growth. An exce])tion to this, however, occurred in case of 

 Tyson, which made tlie best growth on French roots. 



" (6) The treatments ilid not seem to produce any marked effect on stocks so far as 

 rendering them more easily budded. These lesnlts may iu a measure be accounted 

 for, however, by the fact that the leaf-blight diseases were not so severe during the 

 early part of the season of 1)^91 as usual. ■ 



