162 TREES IN" WINTER 



pentine 20 parts, coal tar 10 parts. With tall trees it is usually 

 necessary to get up among the branches. 



Since the caterpillars feed mostly at night and congregate on 

 the trunk of the tree during the day, it is possible to trap many of 

 them under burlap bands. A simple band may be made up by 

 tying a piece of cheap burlap, eight inches in width^ around the 

 trunk and turning the upper edge down over the string. The bands 

 should be examined every afternoon and the trapped insects 

 brushed off into a pail of kerosene and water. 



When infested trees have been sprayed with arsenate of lead (12 

 pounds to 100 gallons of water) soon after the leaves appear, and 

 while the insects are small, good results have followed. The full- 

 grown caterpillars are more resistant to arsenical poisons and may 

 feed upon the sprayed foliage for a long while before they get 

 enough to kill them. 



Slugs — The larvae of certain insects known as saw-flies, are 

 slimy-looking creatures and are called slugs. One species is quite 

 troublesome on the Pear, another on the Willow, and the most de- 

 structive of all on the Larch. The slugs vary in size according to 

 the species; the species affecting the Willow being over an inch in 

 length, while that on the Pear is less than a half inch. The slugs 

 appear in the spring and lavishly feed upon the developing foliage. 

 They are readily controlled by spraying with arsenate of lead at ord- 

 inary strength. 



Another insect belonging to this class is known as the Maple leaf- 

 stem borer. It has entirely different habits from those just de- 

 scribed. The adult lays its eggs in the leaf-stalk at the base of 

 the blade of the leaf. The young larva tunnels inside the stem, 

 eating out the tissue. The affected blades break off and fall to the 

 ground about June first. The stems containing the insects remain 

 attached to the ground where they pupate and emerge the following 

 spring as adult saw-flies. 



The insect attacks the Sugar, Norway and Sycamore Maples. It 

 is not widely distributed and seldom causes serious injury. Spray- 

 ing the ground well with kerosene emulsion about June 15th when 

 the larvae are going into the soil, has been suggested. 



Spiney Elm Caterpillar — This is the name applied to the 

 larva of the common "mourning cloak" butterfly. Besides the 

 Elm, it feeds on the Poplar and Willow. In some seasons it be- 



