79° CONNECTICUT EXPERIMENT STATION REPORT, I907-I908. 



"There have been practiced different methods for the pro- 

 tection of our elm trees, and the cheapest and best is to cover 

 the body of the tree two or three feet from the ground with 

 paper smeared with printers' ink. This is better than the applica- 

 tion of tar, for it remains sticky much longer. It does not gloss 

 over like tar. It is the cheapest application that can be made, 

 and has been tried with success in some parts of New Haven 

 City. It must be put on in the fall and in the spring. 



"The trees about the colleges were provided with a leaden 

 rim surrounding the tree, fitting it like a collar, and having a 

 hollow filled with oil between the rim and the tree. The idea 

 was that the canker worm would tumble off in trying to climb 

 around the shelving edge, or if he succeeded in getting around 

 this that he would die in attempting to cross the intervening fluid. 

 These were found not to work well. 



"The best protection against these worms and other pests is 

 to have their natural enemies flourish at the same time. There 

 is an enemy of the canker womf, a green beetle, which has an 

 enormous appetite, for they eat all the while. These beetles and 

 the birds which live upon the pests of our trees are our best safe- 

 guards against the attacks of the worm. 



"There is also a fly called the ichneumon fly, which attacks the 

 eggs of the canker worm and blights them. All these enemies of 

 the canker worm kill it, and diminish their numbers, so when it is 

 noticed that during some seasons our trees are comparatively free 

 from the worm, you may be sure that this decrease is owing 

 to the fact that their natural enemies have increased in a corre- 

 sponding ratio. When these enemies of the worm also die off, 

 then you will notice that the elm trees are beginning to be laid 

 bare again. And as one end of the scale goes up, the other end 

 goes down." 



Mr. T. S. Gold* made the statement that canker worms are 

 abundant only on light soils, and advised as remedies fall plowing 

 and the use of guards around the trunks treated with oil or tar, 

 to prevent the wingless females from ascending to lay their eggs. 

 At a similar meeting in 1881, Mr. P. M. Augur advisedf spraying 

 with a weak solution of Paris green or London purple as soon 



♦Report Conn. Board of Agriculture for 1866, p. 204. 

 t Idem 1881, p. 334. 



