44 



bered, as explained elsewhere, that the necessity we were under 

 to keep the party at work in g-ood weather and bad, whenever work 

 was at all possible, increased the averag-e cost of fumigation per 

 tree above what it would have been if our men could have been 

 laid by in bad weather without expense, or could have been other- 

 wise profitably employed. 



At Sparta 2,297 trees were fumigated on seventeen different 

 premises— an average of 135 trees at each place. 1,160 lbs. of 

 cyanide of potassium and 290 gallons of common sulphuric acid 

 were used in this work, at a cost of $412; and 1,700 hours of labor 

 were required, at 10 cents an hour. The total expense was $582 — 

 an average of 25 cents a tree. 



At Richview, where the trees were smaller and conditions were 

 more favorable generally, 3,879 trees were fumigated on seventeen 

 different places, an average of 228 trees on each. 994 lbs. of cya- 

 nide of potassium and 248 gallons of sulphuric acid were used, at a 

 cost of $353; and the bill for labor was $113 for 1,130 hours — an 

 average, all told, of 12 cents a tree. 



Taking both places together, the cost of the mere fumigation of 

 6,176 trees was $1,048, or approximately 17 cents a tree. Compari- 

 sons of effectiveness and cost by this and other methods will be made 

 later in this article, after a detail and discussion of the results of 

 the use of the fluid insecticides. 



Treatment with Whale-oil Soap. 

 Our experience in the treatment of many thousand trees with 

 this well-known insecticide, prepared in the usual strength of two 

 pounds to the gallon of water, has merely served to confirm the 

 common conclusions with respect to it. It has proved to be very 

 efficient for the destruction of the scale, killing practically all 

 reached by it ; has done no injury to trees or shrubs ; but has 

 proven dangerous to the fruit buds of the peach unless applied in 

 spring after the buds begin to swell. It is much the most expen- 

 sive of the sprays of which we have made use, costing at the rate 

 of $6.50 per hundred gallons, and has also been the most inconre- 

 nient of application in cold weather. This solution is only fluid 

 while warm, becoming of a semi-gelatinous consistency when 

 entirely cool, and if, owing to the clogging of the nozzle, it was 

 necessary to stop its flow for a little time, the delivery hose was 

 sure to clog and fill if the weather was much below freezing. Our 

 ■work was all done with potash soaps, but I have made no compar- 

 ative tests of these and soda soaps, and have failed to find any pub- 

 lished evidence in support of the very common preference of the 

 former as an insecticide. 



