CHAPTER XVI 



Repellents 



Occasionally some chemical is found to be of service in driving away 

 insects at work on a plant. Many remedies of this nature are pro- 

 posed from time to time, but in most cases further tests prove that 

 they are without real value. 



Dry-slaked lime is of service in driving away certain pests, such as 

 the striped cucumber beetle. To prepare, place fresh lump lime in a 

 metal vessel and add a small amount of hot water. The lime will 

 slake to an extremely fine powder. This is dusted on the insects. 

 If desired, flowers of sulphur may be added to the slaked lime. 



Tobacco dust is reasonably effective as a repellent. It must be 

 fresh, and is dusted directly on the insects; or when used as a pre- 

 ventive of attack by root maggots, the dust is heaped up around 

 the stem of each plant. 



Naphthaline, or " moth balls," is of moderate value as a repellent 

 for such insects as the common clothes moths, or for some of the 

 pests that infest dried animal products. This material is not, how- 

 ever, a complete protection. It should be noted, further, that if 

 moths have already laid their eggs on garments, and the latter are 

 afterwards packed away with naphthaline, no benefit whatever will 

 be s'ecured. The substance is a repellent solely for the adult moth, 

 and not for the larva, which does the real damage. 



Protective Wash for Trunks of Trees 

 Dissolve 2 quarts of strong soft soap in a bucket of water. One 

 pound of hard soap may be used instead of the soft soap. Add ^ 

 pint of crude carbolic acid and 2 ounces of Paris green. Then add 

 lime, or clay, or both, so as to make a thick paste. 



Paint this on the trunks or limbs of trees as a deterrent for borers. 

 It will not give entire protection, but will help to ward off attack. 



79 



