THE SPRING CANKER-WORM. 21 



and preclaceous enemies is evident from the fact that in a near-by 

 orchard, untreated, the insects Avere excessively numerous, comj^letely 

 defoliating the trees during the spring of 190G. Figure 1, Plate IV, 

 is from a jjliotograph of trees in the worst infested portion of the 

 Lupton orchard in 1J)05, and shows the injury that had been done 

 before the application of the Paris green spray. The condition of 

 these same trees, but looking in another direction, on June 9, 190G, is 

 shown in figure 2. 



During the spring of 190(> sprayiug work against canker-worms 

 was also carried out in another orchard near Winchester consisting 

 of 30 acres of 35-year-old Baldwin trees. This orchard also had been 

 entirely neglected as to plowing and si^raying for many years past, 

 and for some years most of the trees had been comi)letely defoliated 

 by the spring canker-worm, some of them and portions of others 

 being dead. Arrangements were made to spray a portion of the 

 orchard, though it was not considered practicable by the owner to 

 have the ground plowed. Arsenate of lead was used as a poison and 

 applied at the rate of 3 and 5 pounds per 50 gallons of water for the 

 first and second applications, respectively. At the time of the first 

 application the leaves were Avell out, being from three-fourths of an 

 inch to an inch in diameter. The canker-worms had almost all 

 hatched, very man}' being in the second stage, and were literalh' 

 swarming over the trees. The second application was made ^lay 5, 

 most of the larva^ at this time being from one-half to three-fourths 

 grown, the untreated trees being already nearly bare of leaves. The 

 treated trees, while showing some injury from the larvie, especially 

 in the higher parts, were in almost full foliage, though subject to 

 infestation from adjacent trees. The second application largely pro- 

 tected the trees from further injur}', and there is no doubt that if the 

 entire orchard had been treated the insects would have been practi- 

 cally exterminated. P'igure 3, Plate IV, shovrs the defoliated condi- 

 tion of untreated trees June 9, after the larva^ had all disappeared, 

 and the condition of sprayed trees in an adjacent row is shown in 

 figure 4 on the same plate. 



RECOMMENDATIONS. 



Orchardists having canker-worms to contend with may confidently 

 expect to practically eradicate them in the course of one or two sea- 

 sons by following the methods above described, namely, thoroughly 

 spraying the trees with a strong arsenical and thoroughly plowing 

 the ground during the summer. If Paris green is used, this should 

 be applied at the rate of 1 pound for each 100 gallons of water, and 

 unless used in Bordeaux mixture there should always be added the 

 milk of lime made from slaking 4 or 5 pounds of good stone lime. 

 Arsenate of lead may be used at the rate of (> to 10 pounds to 100 



