EXPERIMENT STATION BULLETINS. 183 



best to dust with, something beside arsenicals. The writer has used 

 dry -slaked lime and sulphur -for many years and with very good results. 

 Slake the lime dry (air-slaked lime is not as good, for it is not so caustic 

 in its effects). See directions on page 66. Mix one pound of flowers of 

 sulphur with every three pounds of dry-slaked lime and dust on through 

 coarse cloth. Three or four thicknesses of mosquito-netting works 

 better than anything else. Dust on liberally and repeat as the vines 

 grow or rain washes off the old coating. The beetles detest the mixture 

 and if the plants are kept covered, their work will be comparatively 

 insignificant. Weekly applications are usually enough. 



Tobacco-dust, or finely ground tobacco thrown about the roots, works 

 very nicely. The writer uses half a handful to a plant. It can be ob- 

 tained at from one to two cents a pound from the large tobacco factories 

 in the South or from their representatives in the cities. Tobacco-dust 

 is a valuable fertilizer besides killing many insects. By combining these 

 two practices one should be able to raise good crops of cucumbers in 

 spite of the beetles. As the beetles hibernate as adults, clean culture 

 will exert a marked beneficial influence. Plow up the fields just as soon 

 as the crop is gathered. 



Cucumber Flea-beetle (see Potato Flea-beetle). 



INSECTS AFFECTING THE HOP. 



INSECTS AFFECTING THE FOLIAGE. 



Hop Merchant (Polygonia comma). 



The spiny caterpillar of the hop-merchant is known to all hop grow- 

 ers. After a time, these caterpillars change to the naked pupae which 

 are marked with golden or silver spots. From these pupae come the 

 adults, very pretty butterflies of a general brownish color, marked with 

 darker brown and slate. On the underside of each hind-wing is a silver 

 mark, shaped like a comma, from which the insect takes its latin name. 

 The eggs are laid in strings on the leaves. Besides hops, the caterpil- 

 lars feed on elm and nettle. 



REMEDIES. 



The only remedies are hand picking and spraying with arsenical poi- 

 sons early in the season. After the hops form, no sprays should be 

 applied because of danger from poisoning. 



The Violet-tip {Polygonia interrogationis) . 



The violet-tip closely resembles the hop-merchant. It is, however, 

 larger and the greys on the wings are apt to take on a more purplisli 

 tint. Each hind-wing is marked with a silver spot something like an 

 interrogation mark. The larvae feed on nettle, elm and hackberry as 

 well as on the hop. 



