l88 BULLETIN NO. 54. [M(irc/l, 



Some Spraying Experiments. 



The Illinois Experiment Station has, since its inception in 1888, 

 annually carried on experiments with insecticides and fungicides and 

 their use for controlling fruit enemies. While many valuable results 

 have been obtained from time to time as a consequence of these syste- 

 matic and thorough investigations, they were in most instances merely 

 duplications of work carried on and published by other stations. More- 

 over, these were conducted upon plants which were grown for some 

 purpose other than the direct test with spraying solutions, and lacked 

 the material for illustration which could only be secured by operations 

 carried on in commercial orchards. Accordingly, in the spring of 1898, 

 these were supplemented by a thorough set of experiments carried on 

 for the most part in several acres kindly offered for the purpose by 

 Mr. H. M. Dunlap of Savoy. These experiments were inaugurated for 

 the sole purpose of furnishing accurate illustrations of what could be 

 accomplished in Illinois by thorough and systematic spraying, and by 

 varying degrees of thoroughness. They had for their object a consid- 

 eration of the best methods for controlling apple scab fungus, codling- 

 moth and scurfy bark louse. The latter will not be considered in the 

 present discussion. For the sake of brevity the details of this work will 

 be omitted, giving only the results obtained, which are well illustrated 

 in the accompanying plates. 



Applications Made. 



It should be borne in mind that both the apple scab fungus and the 

 codling-moth were in no instance treated separately. That is to say, 

 when Paris green was applied for the sake of experimentation in con- 

 trolling the codling-moth, it was done only in connection with the Bor- 

 deaux mixture, thereby furnishing a like experiment for the scab. This 

 was because of the fact that it is no longer deemed advisable to make 

 separate applications for these two pests, since one is entirely sufficient 

 and the time and labor saved by combining the two is great. 



Trees were first treated with the copper sulphate solution March 3 1 st, 

 and the last application of this was made April 8th. This solution was 

 applied in varying strengths to different trees, using in some cases one 

 pound to fifteen gallons of water, while in others one pound to ten gal- 

 lons of water and one pound to five gallons of water was tried. A care- 

 ful examination by Mr. Clinton, Assistant Botanist of this Station, made 

 May 6th, revealed the fact that trees so treated had a much smaller per- 

 centage of scab than than those not treated. At this date too he found 

 that the trees treated with the strongest solution of copper sulphate had 

 very little or no scab on the young leaves, while in the case of the one- 

 to-ten solution they were not so free, and on those treated with the one- 

 to-fifteen solution there was considerable scab present. These stronger 



