84 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



the hop flea-beetle. Being more adhesive, this mixture, when sprayer! 

 npon the plants, sticks more firmly to the leafage than Paris green, 

 and is also very much less likely to produce scorching or burning; 

 indeed, it has been used at 1 pound to 10 gallons of water on some of 

 the hardier plants, such as potato, without injurious effects. This is, 

 however, not advisable, owing to the extra cost, provided that a 

 weaker solution will accomplish the object. Moreover, scorching is 

 apt to follow its use at this rate on some plants, especially when these 

 are exposed to the direct rays of the sun. The adhesiveness is still 

 further enhanced by the addition of about the same amount by 

 weight of resin-fishoil soap as of the arsenical employed. Mr. Wil- 

 son reported that arsenate of lead, applied at the rate of 4 pounds to 

 40 pounds of Bordeaux mixture, was inadequate, yet Mr. Quayle re- 

 ports that used at the rate of 5 pounds to 50 gallons it will kill a 

 large number of the beetles, although many take to the new growth 

 that is constantly appearing, or apparently carefully avoid those 

 places on the foliage that have a good coating of poison. The failure 

 of these two arsenicals must be attributed, in large part, to unsuitable 

 spraying apparatus; either of these applications should kill insects 

 on hops, as they have both been found effective, according to Fletcher, 

 against this same beetle on rhubarb in the Northwest Territory and 

 Manitoba. 



Dry Paris green. — Mr. Thos. Cunningham reported that very 

 little impression was made by an arsenical spray in the region just 

 mentioned, but stated that Paris green dusted on the plants seemed to 

 produce better results. It was applied by means of a Leggett powder 

 gun. Even then some trouble was experienced; in fact, as the 

 arsenical dust or so-called " dust spray " struck the vines the " fleas " 

 hopped to the ground. " In all my experience with insecticides," he 

 says, " I have never seen anything which will approach the fleas in 

 resistant power." 



Paris green spray. — Paris green, being the most readily obtainable 

 insecticide, was advised by this Bureau Avhen information as to 

 remedies w^as requested. When properly prepared and applied, 

 according to the directions furnished in Farmers' Bulletin No. 127, 

 this insecticide should have no deleterious effect on the hop or other 

 plants affected. It was advised that other food plants growing in the 

 vicinity, such as rhubarb, turnips, and weeds, should be sprayed with 

 the solution. 



Regarding its efficiency in hop fields Mr. John Wilson, in a report 

 to the late Doctor Fletcher, stated that when applied at the rate 

 of from 4 to 8 ounces, in combination with Bordeaux mixture, made 

 according to the 4-4-40 formula, or in 40 gallons of water, it was not 

 successful. 



