1908.] PUBLIC DOCUMENT — No. 33. 133 



Summary. 



I. Of the sprays used this year on the experimental plots, 

 the soda Bordeaux and Paris green was the best. It adhered 

 to the leaves the best of any used, it did not color the foliage 

 greatly, and effectively prevented the plants from being injured 

 by either fungi or insects. In mixing this spray, however, 

 great care should he taken to add sufficient lime to make the 

 mixture slightly alkaline, otherwise serious leaf hum might 

 result. 



II. Bordeaux and sodium benzoate ranked a close second in 

 effectiveness, and hardly any discrimination can be made be- 

 tween the soda Bordeaux mixture and the benzoate mixtiu-e. 

 This mixture colors the leaves scarcely at all, and adheres about 

 as well as the soda Bordeaux. The sodium benzoate could be 

 added in slightly larger amounts without injury to the plants. 



III. Bordeaux and " Disparene " seemed to be productive 

 of fairly good results, and held the blight and insects well in 

 check. It did not, however, give such good results as the first 

 two mentioned. It showed up well on the foliage, coloring it 

 heavily, and it adhered well to the leaves. 



IV. Bordeaux and Paris green did not seem to hold the 

 diseases in check as w'ell as some of the other sprays, and did 

 not adhere as well to the leaves ; nevertheless, it was produc- 

 tive of good results. 



V. Copper phosphate and " Disparene " seemed to have no 

 appreciable effect on checking the disease, and this jxar's re- 

 sults, at least, seem to indicate that it is not equal to other 

 funoficides. 



& 



10. Influence of Various Potash Salts on Potato Scab 

 (Oospora scabies, Thaxter). 



In connection with the preceding spraying experiments on 

 potatoes, observations were made on the occurrence of potato 

 scab in the various plots treated with different combinations of 

 potash.^ As previously stated, there were five series, each 

 containing eight plots, fei-tilized with seven different potash 

 compounds, with normal or untreated rows between the ferti- 



1 See report of agriculturist, p. 39, for details as to fertilizer. 



