The Control of Insect Pests and Plant Diseases. 587 



plant and through them the insects suck out the sap. Examples: Squash 

 stink-bug, San Jos^ scale and plant lice (Fig. 191). 



Chewing insects are usually controlled by applying to their food poi- 

 sons such as Paris green, arsenate of lead or hellebore. Sucking insects 

 cannot be reached in this way and must be killed by a direct applica- 

 tion of contact insecticides, such as soaps, oils, 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 insects, 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 page 498. 



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 

 water. Repeat the application after the blossoms fall. Prevent the ascent of the 

 wingless females by means of sticky bands or wire-screen traps. 



This is the pinkish caterpillar which causes a large proportion 



Codling-moth, of wormy apples. The eggs are laid by a small moth on the 



(Fig. 192.) leaves and skin of the fruit. 



Most of the caterpillars enter 

 the apple at the blos.som end. When the petals fall 

 the calyx is open (Fig. 193), and this is the time to 

 spray. The calyx soon closes and keeps the poison 

 inside ready for the young caterpillar's first meal 

 (Fig. 194). After the calyx has closed, it is too 

 late to spray effectively. The caterpillars become 

 full grown in July and August, leave the fruit, 

 crawl down on the trunk, and there most of them 

 spin cocoons under the loose bark. In most parts 

 of the country there are two broods annually. p^^ ^ ^2. -Codling-moth cater- 



Immediately after the blossoms fall spray pillar in the 'apple. 



with 1 lb. Paris green or 4 lbs. arsenate of lead 



in 100 gals, of water. Repeat the application about 3 weeks later. For use with 

 Bordeaux and lime-sulfur see apple scab (page 486). Use burlap bands on 

 trunks, killing all caterpillars under them every ten days from July ist to 

 August ist, and once later before winter. Cornell Bulletin 142. 



The small white maggots xnrke brownish winding burrows in 

 Apple-maggot the flesh of the fruit, particularly in summer and early fall 



varieties. This insect cannot be reached by a spray as the 



