twelve] our rivals — the INSECTS 



I have not given space to a discussion of the oil 

 remedy, because there is so much danger of serious 

 damage being done by amateur workmen. If, 

 however, you care to experiment with crude petro- 

 leum to destroy scale insects or aphides, I advise you 

 not to use a stronger than twenty-five per cent, mix- 

 ture. In peach orchards I should use it with still 

 greater caution. Pure crude petroleum was for a 

 while recommended to be used in very fine spray, 

 but a vast amount of damage was done. 



I shall not pass away from this discussion of in- 

 secticides, involving a free use of arsenical mixtures, 

 without warning you that these poisons cannot 

 be used without more or less danger. Some of 

 us cannot handle or come in contact at all with 

 these spraying materials without serious injury. 

 A great deal too much arsenic is used in potato 

 fields, and elsewhere. The storing of it is often 

 very careless. Arsenic, even when used in the 

 form of spray, and blown about by the wind, is nfjt 

 inhaled by the lungs wi h impunity. I give you, 

 therefore, a word of sharp caution in the handling 

 of this poison and its application. 



A large number of insects are very migratory in 

 their habits. They are always coming and they 



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