DISEASES OF PLANTS. 761 



show the weights of air dry plants in the different pots, are tabulated, 

 in which it appears that "sulphur employed in considerable quantities 

 upon soils which are acid or which contain but a limited excess of 

 basic ingredients is capable of causing much subsequent injury to 

 crops, the extent of the same being greatest upon acid or neutral 

 soils." It is further stated that the application of sulphur to soils for 

 the preyention of potato scab regardless of the character of the soil 

 is liable to occasionally cause much injury. The authors state that 

 sulphate of ammonia, which has a high manurial yalue, giyes promise 

 of being more satisfactory and economical than flowers of sulphur as 

 a means of lessening the tendency to scab in contaminated soils which 

 are fayorable to the growth of the fungus. 



Experiments in the prevention of tomato blights, G. H. Pow- 

 ell {JJtIaivare Sta. Rpt. ISOO^pJ)- 1-^-^-ioO). — Reports are giyen of 

 experiments in spraj'ing tomato plants in 1898-99 with Bordeaux mix- 

 ture for the preyention of tomato blights. In 1898 yarious plats 

 were sprayed at different times and with different numbers of appli- 

 cations. The results obtained were of a decidedly conflicting nature, 

 some of the check plats yielding more than some of the sprayed ones. 

 The results obtained indicated that Bordeaux luixture did not check the 

 progress of the disease, although it was yisible upon the foliage 

 throughout the season. 



In 1899 the experiments were repeated. One lot of 100 plants was 

 covered with Bordeaux mixture from the time of their appearance 

 aboye ground until the ripening of the first fruits; a similar lot was 

 kept thoroughly spraj-^ed from the time the plants were set in the field 

 to the ripening of the first fruits; a third lot was sprayed from the 

 time of setting first fruits to their ripening, and a fourth lot was 

 retained as a check. Records were kept of the numl^er, weight, and 

 diseased character of all the fruits, the results of which are shown in 

 tabular form. The plants sprayed from the time of their appearance 

 in the seed bed gained at the rate of 2.1:5 tons per acre; those sprayed 

 from the time of setting in the field, 1.21: tons; while those sprayed 

 from the time of the setting of first fruits until their ripening gained 

 2.25 tons per acre. The tomato blight appeared on none of the plants 

 until late in the summer, after which all the plants seemed to be 

 affected alike, the foliage dropping from the sprayed as well as the 

 check plants. 



The yalue of Bordeaux mixture in these experiments seems to be 

 shown in the increased yigor of the plants, haying stimulated them to 

 a more rapid growth. It was of particular merit in keeping down the 

 attacks of flea-beetles, and spraying the seed bed is thought advisable 

 by the author, especially if it should be on land preyiously set to 

 tomatoes. 



Report on the treatment of apple scab, 1898. F. D. Chester 



