120 MAINE AGRICULTURAL EXPERIMENT STATION. I908. 



THE EFFECTIVENESS OF PREPARED BORDEAUX MIXTURES, WET 

 AND DRY COMPARED WITH FRESHLY PREPARED. 



Wet read-to-use Bordeaux mixtures were compared with 

 freshly prepared Bordeaux mixtures by the Station in 1900 * 

 with the result that when these mixtures were used according to 

 directions, the results were not as effective as the freshly pre- 

 pared Bordeaux mixture. This was probably due to the fact 

 that when the directions are followed, a much smaller amount of 

 copper is used per acre than in the freshly prepared Bordeaux. 



In one instance in 1900 a ready prepared Bordeaux mixture 

 was used in sufficient quantity to furnish as much copper as is 

 carried by ordinary Bordeaux mixture. 



The results of the experiments indicated that ready prepared 

 Bordeaux mixtures were about as effective as freshly made 

 goods provided they were used in such amounts as to supply an 

 equal amount of copper. 



In 1907, a field experiment was made on quite a large scale 

 the primary object of which was to compare dust spraying with 

 wet Bordeaux. However one ready prepared wet Bordeaux 

 (Boxal) was used. The results are reported in detail in Bulle- 

 tin 149 of this Station and are shown graphically on the opposite 

 page. 



So far as the results of the experiments show, none of the 

 substitutes for wet bordeaux in any way approached it in effi- 

 ciency as a preventive for late blight. While none of the dust 

 sprays in any way produced the results claimed for them by the 

 manufacturers and others, they all showed more or less fungi- 

 cidal value. This was least with Leggett's Blight Dust No. 2 

 and Bowker's Dry Boxal, which only showed a gain of 18 or 

 20 bushels per acre resulting from 6 applications of 6 pounds 

 each, when compared with the unsprayed check. The same 

 amount of Dust Sprayer Manufacturing Co's. Sal Bordeaux 

 increased the yield 60 bushels per acre, while 10 pounds of the 

 same material to an application gave an increase of 102 bushels 

 per acre. The fact should not be overlooked that wet bordeaux 

 under the same conditions gave an increase of 168 bushels per 

 acre. 



* Bulletin 73, Maine Station. 



