SHADE TREE INSECTS 15 



blown to other trees by the wind. In early June the caterpillars drop or crawl to 

 the ground, spin cocoons just below the surface of the earth, and there pupate, 

 the adult moths appearing in late fall to lay their eggs. There is only one genera- 

 tion a year. 



The moths of the spring cankerworm emerge from cocoons in the ground late 

 in the winter or ver}' early in the spring. The wingless females climb the trees 

 and lay their eggs in loose irregular clusters in crevices on the bark. These eggs 

 hatch about the same time as those of the fall cankerworm and the caterpillars 

 feed on the leaves, causing the same type of injury. They mature in early June 

 and then go to the ground to pupate in cocoons. There is one generation a year. 



Control. 



1. Sprays. Adequate control can generally be obtained by spraying with 

 lead arsenate in the spring as soon as the leaves are large enough to hold a poison 

 spray. Powdered lead arsenate may be used at the rate of 4 or 5 pounds to 100 

 gallons of water with 2 pounds of flour or 1 pound of calcium caseinate added as a 

 sticker. If only one application is to be made, it should not be applied too early, 

 because the leaves which develop later will not be poisoned and so may be eaten. 

 However, in severe infestations the caterpillars may cat the leaves as fast as they 

 appear, at no time leaving enough leaf surface to poison. In this event, before 

 much damage occurs, it may be advisable to spray with or add to the lead arsenate, 

 a contact insecticide such as 40 percent nicotine sulfate. This may be added to 

 the lead arsenate in the proportion of 1 pint to 100 gallons of the lead arsenate 

 spray. Rotenone, derris, or pyrethrum may be substituted for the nicotine sulfate 

 and should be mixed according to the directions of the manufacturer. All these 

 contact sprays kill by touching the insect, so care should be taken to hit the 

 insects directly. Because the young opening leaves are more susceptible to spray 

 burning than older ones, it would be safer to apply not more than 3 pounds of 

 lead arsenate in 100 gallons of water to foliage sprayed at that time. If a later 

 application is necessary, 4 or 5 pounds of the powder may be used. 



Spraying with lime-sulfur or nicotine sulfate in the spring before the buds 

 begin to swell, has also been advised, to kill the eggs in localities known to be 

 heavily infested. The lime-sulfur spray may be mixed in the proportion of 1 

 part of liquid lime-sulfur {ii° Baume) to 9 parts of water. The nicotine sulfate 

 spray may be mixed in the proportion of 1 pint of 40 percent nicotine sulfate to 

 100 gallons of water. 



2. Sticky Bands. Because of the wind drift of the insects, banding is not 

 advised where the trees to be protected are close together. However, banding 

 should prevent severe injury to trees not yet infested which stand off by themselves. 

 Sticky bands can be placed around the trunks of isolated trees in late October to 

 prevent the wingless moths from climbing to lay eggs. These bands should be 

 kept sticky during November and December for the fall cankerworm moths. 

 They should be renewed in the early spring just before the frost leaves the ground 

 and kept sticky until the end of May to prevent the wingless moths of the spring 

 cankerworm from ascending to lay their eggs in the early spring, and to prevent 

 the caterpillars from crawling up to feed when the leaves appear. 



It is best to place the sticky bands on strips of cheap cotton batting, which 

 should securely fill up all bark crevices to prevent insects from crawling through 

 'underneath. Regular banding strips are for sale on the market. 



Britton, W. E. Conn. State Ent. Rpt. 34:213-220. 1935. 



Britton, W. E., and Friend, R. B. Conn. Agr. Exp. Sta. Bui. 369:269-272. 1935. 



Fernald, C. H. Hatch Exp. Sta. Mass. Agr. Col. Bui. 20:4-6. 1893. 



Hartzell. A., and Youden, W. J. Contrib. Boyce Thompson Institute 7(3) : 365-377. 1935. 



McDaniel, E. I. Mich. Agr. Exp. Sta. Spec. Bui. 243:30-33. 1933. 



