AGRICULTURAL TEXT-BOOK. 135 



313. A great variety of preventives have been tried, but 

 only a few appear to be worthy of use. Salt, perhaps, is the 

 most generally successful against such grubs as live in the 

 ground : Two to four bushels per acre of fine salt being sown 

 broadcast, and slightly harrowed in, a few days before planting. 

 If the corn is to be planted on sod, Ml plowing late in the 

 season will affect some good ; also steeping the grain in salino 

 and ammonical liquors ; and tarring. It has been recommended, 

 and practised with success, to hang the seed corn in the smoko 

 house, and smoke it with the hams : the pyrol igneous acid ap 

 pears to be offensive to insects and birds, while it does no injury 

 to the grain. For insects injuring the ripe corn when stored, 

 abundance of air, and thorough ventilation are the best preven 

 tives. A barrel, impregnated with tar, it is said will drive 

 away the True Grain Weevil, ( C. granarius,) (g,) if it is 

 placed in the granary. It is thus employed in France. 

 The farmer will find much profit in cherishing birds; even 

 the red-winged Black Bird, (Agelaius phoeniceoeus,) and Crow 

 Black Birds, (Qidscalus versicolor and ferrugineus,) on his 

 farm ; for though they destroy some grain, it is but a choice of 

 two evils; it being always found that where birds are driven 

 away the loss by insects becomes extreme. A single pair of 

 Crow Black birds will, in one season, destroy thousands of in 

 jurious grubs. 



The whole subject of insects injurious to vegetation in America, still 

 requires much study and persevering observation ; and notwithstanding 

 Dr. Harris labors, there is yet much of practical importance to learn 

 regarding it. &quot;We believe that the day will come when means will be 

 discovered of preventing these ravages ; but before this can take place, 

 not only must the habits of the insects themselves, but also the peculiar 

 ities of the plants and soil be much better understood than at present. 

 Many facts would lead us to believe, that an impoverishment of the soil 

 is necessary before insects can become seriously injurious, as it is cer 

 tainly connected with diseases of vegetation. 



314. Many of the European physiologists, have for a length of time 



