90 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 47 



CONTROL MEASURES 



Following are the control measures mentioned on previous 

 pages of this circular. In most instances, formulas given are for 

 100 gallons of spray. The amounts of insecticides to be used for 

 small quantities of spray can be calculated from information 

 given in tables 1 and 2, page 89. 



Control Measure 1. — Apply a lead arsenate spray: 4 pounds 

 of lead arsenate to 100 gallons of water. 



Control Measure 2. — Apply a DDT spray : 2 pounds of 50 per 

 cent DDT wettable powder or 2 quarts of 25 per cent DDT emul- 

 sifiable concentrate to 100 gallons of water. Both lead arsenate 

 and DDT are effective against most leaf-eating insects. Where 

 either insecticide will do the job, lead arsenate (Control Measure 

 1) should be used, because of the aphid and mite infestations 

 likely to follow repeated use of DDT. 



Control Measure 3. — Apply a malathion spray : 1 quart of 50 

 per cent malathion emulsifiable concentrate or 4 pounds of 25 

 per cent malathion wettable powder to 100 gallons of water. 

 CAUTION: Malathion may injure Canaert red cedar, Juniperus 

 virginiana canaertii. 



Control Measure 4. — Prevention of borer attack is more suc- 

 cessful than attempts at a cure. To discourage borer attack, keep 

 the trunks of newly set trees wrapped with heavy paper for the 

 first 2 years, or until the trees are established and growing vig- 

 orously. Special paper, 3 to 4 inches wide, in rolls suitable for 

 spiral wraps can be purchased. Start the wrap just below the 

 lowest branch and spiral it downward to the ground. Heap soil 

 around the base of the tree to close the space between the wrap 

 and the ground. Secure the wrapping in place with stout twine, 

 fig. 54. Keep the soil well watered, as drought-weakened trees 

 are attractive to borers. 



Borer attack can be prevented, for the most part, by a DDT 

 spray applied to tree trunks: 4 pounds of 50 per cent DDT wet- 

 table powder or 1 gallon of 25 per cent DDT emulsifiable concen- 

 trate to 100 gallons of water. Designed to kill young borers as 

 they hatch from eggs on the bark, the spray should be applied 

 at monthly intervals throughout the summer, beginning about 

 May 1. Application of DDT to the entire tree is not recommended 

 unless necessary, as such application may result in serious infes- 

 tations of mites and aphids. A durable insecticide deposit can be 



