62 BOARD OF AGRICULTURE. [Pub. Doc. 



Formula 4a. Lead Arsenate* 



Lead arsenate, 1 pound. 



Water, 50 gallons. 



Arsenate of lead acts slower as a poison than Paris green. 

 It can be kept suspended in the water better than Paris 

 green ; it does not burn the foliage and sticks to it better 

 than Paris green. For these reasons it proved, in our ex- 

 periments in 1900, more satisfactory than Paris green. 



Mr. Christopher Clark (of Northampton). I consider 

 arsenate of lead by far the most effective insecticide that can 

 be used. It is also a perfect remedy, almost, for the Colo- 

 rado beetle. During the past two years I have noticed 

 where persons have used Paris green on one field it had to 

 be applied three or four times, and where arsenate of lead 

 was used it had to be applied only once. 



I consider the addition of glucose to the spraying mixture 

 very important. I found that out by experiments on shade 

 trees. In recent publications in regard to the use of arse- 

 nate of lead as a remedy against the Colorado beetle the 

 glucose was left out, which should not be, because, if you 

 spray the potato vines when they are not wet, or spray the 

 trees when the leaves are not thoroughly wet, you will see 

 the difference in the adhering qualities. The arsenate of 

 lead will adhere to the leaves through the heaviest thunder 

 storms, whereas with Paris green applied in the ordinary 

 way a very large percentage would be washed off entirely. 



I have found that arsenate of lead can be used freely upon 

 maples, that have most delicate leaves ; and it is a most 

 effective remedy for the lice that attack the maple leaves 

 and cause them to fall off quite early in the season as if they 

 were dead, and because of which so many people have 

 thought their maple trees were dying. 



Professor Woods. Arsenate of lead is considerably supe- 

 rior to Paris green, and, while we have not experimented as to 

 how little could be used, we have used a pound of arsenate 

 of lead, as against half a pound of Paris green. At this rate 



* Swift's lead arsenate or Bowker's disparene. 



