337 



prepared by an authority in that particular field. Study aiid follow the 

 directions carefully, apply the remedies in time and with thoroughness, 

 and in case of failure or difficulty write to the Cornell Agricultural 

 Experiment Station for assistance. 



11. INSECTS AND THEIR CONTROL. 



M. V. SLINGERLAND AND C. R. CROSBY. 



For purposes of control, insects are divided into two great classes: 



A. Chewing insects, or those having jaws by means of which they 

 bite off and eat portions of the tissues of the plant. Examples: Potato 

 beetle, (Fig. 145) canker-worm and codling-moth caterpillar. 



B. Sucking insects, or those furnished with a beak containing four 

 bristles united into a slender tube. The bristles are inserted into the 

 plant and through them the insects 



suck out the sap. Examples: Squash 

 stink-bug, San Jos^ scale and plant- 

 lice (Fig. 146). 



Chewing insects are usually 

 controlled by applying to their 

 food poisons such as Paris green, 

 arsenate of lead or hellebore. 



Sucking insects cannot be reached „. ^ . , , 1 z ., 



Fig. 146. A plant-louse, one of the suck- 

 in this way and must be killed by mg insects, showtng the beak. 



a 'direct application of contact 



insecticides, such as soaps, oUs or other substances. In fighting sucking 



insects, thorough and skillful work is required since every individual 



insect must be hit by the spray, while in the case of chewing injects, 



it is merely necessary to apply the poison thoroughly to the food-plant. 



APPLE. 



The small brown caterpillars with a black head devour the 

 Bud-moth. tender leaves and flowers of the opening buds in early spring. 



Make two applications of either i lb. Paris green or 4 lbs. arsenate 

 of lead in 100 gals, of water; the first when the leaf-tips appear and the second just 

 before the blossoms open. If necessary, spray again after the blossoms fall. For 

 use with Bordeaux, see apple scab, Cornell Bulletin 107. 



These caterpillars are small measuring-worms or loopers that 

 Canker-worms, defoliate the trees in May and June. The female moths are 



wingless and in late fall or early spring crawl up the trunks of 

 the trees to lay their eggs on the branches. Spray thoroughly once or twice, before 

 the blossoms open, with i lb. Paris green or 4 lbs. arsenate of lead in 100 gals, of 



