50 



INSECTICIDES AND SPRAYING 



5. Hopperdozers. Various forms of these may be constructed 

 to combat grasshoppers or other jumping insects (Figs. 70 and 71). 



6. Ditches may be dug around a threatened crop to prevent 

 inroads by chinch bugs, army worms, field mice, gophers, etc. 

 (see discussion of these pests). 



7. Dust furrows may be used against an advancing army of 

 chinch bugs. 



8. Oil barriers are also used to check chinch bugs where dust 

 furrows are not practicable. 



9. Tarred Paper or Tarred Felt Disks. These are placed on 

 cabbage or cauliflower plants when set out, to prevent eggs of 

 cabbage maggot being placed thereon. 



Fio. 70. Working against grasshoppers with a "hopperdozer." 



10. Covering of Seed Beds and Plants. Cabbage and other 

 plants in coldframes are protected by screens. Melons and cucum- 

 ber plants may be guarded against insect attack until well started, 

 by wooden frames covered on top with cheesecloth. 



Wash for Tree Trunks and Limbs. Several washes for pro- 

 tection of trees against borers are in use. They act as deterrents 

 and some of them as poisons for the young grubs entering the tree. 

 All are more or less effective, but must not be relied upon absolutely. 

 The following is an example: Two quarts of strong soft soap (or 

 one pound hard soap) dissolved in a bucket of water. Add one-half 

 pint of crude carbolic acid and two ounces of Paris green. Then add 

 lime or clay, or both, to make it a thick paste (O'Kane). Probably 

 two applications of this wash during the year would be necessary. 



Never use an oil paint white lead, for example or any form of 

 boiled linseed oil on trunk or limbs. 



