INJURIOUS INSECTS. Ill 



of about fifty gallons each, in a wagon and fill them with water. 

 Then they take a pound of London purple for each barrel, first 

 mixing it well in a pail of water, and pour it into the barrel. The 

 wagon is then driven along the windward side of the row of trees, 

 if there is much wind, and, with a fountain pump having a fine rose 

 attached, the liquid is thrown over the trees in a fine mist till the 

 leaves begin to drip. The water in the barrels must be stirred 

 constantly to prevent the poison from settling. Great care is also 

 taken to prevent the wind from carrying the liquid towards the 

 men or horses. In rainy weather they repeat the application two 

 or three times. With two teams and four men they are able to 

 spray three or four hundred trees in a day, and the cost is set at 

 three cents a tree for twice spraying. 



The above estimate of the cost of spra3-ing trees seems rather 

 low ; still the actual cost must have been known. Professor 

 Forbes, of the Illinois Industrial Universit}-, made some experi- 

 ments in spraying trees to destroy the codling moth, and he esti- 

 mated the cost at ten cents a tree. But he stated that, with 

 proper appliances, it would cost much less. If we estimate the 

 cost of showering an apple tree to be ten cents even, which I have 

 no doubt is twice as much as the actual cost would be, I believe 

 it would then prove to be the cheapest and most eflfectual way of 

 destroying all leaf-eating species, and the most eflfectual method 

 thus far suggested for the destruction of the codling moth. The 

 experimenty of Professor Forbes, conducted witli great care 

 through two seasons, resulted in the saving of seventy-five per 

 cent of the apples which would otherwise have been injured by 

 the codling moth ; and when we take into account the fact that by 

 the same application numerous other insects were destroyed, we 

 must admit that spraying the trees, even at ten cents apiece, is an 

 exceedingly profitable investment. 



Professor Forbes used Paris green in water in the proportion of 

 fifteen ounces of the former to fifty gallons of the latter, and 

 sprayed the trees thoroughly with a hand force-pump, the fluid 

 falling in a fine, mist-like spray upon the leaves until they began 

 to drip. He found by comparative experiments that the Paris 

 green was decidedl}' more efficient than London purple. 



I have no doubt that the above is a larger proportion of the 

 poison than is necessar}' or desirable. Various proportions have 

 been recommended, even as low as one tablespoonful to a barrel 



