69 



fectly effectual. .The lice fell before it as the grain falls before a 

 reaping-machine. 



Statement 6th. — "An ounce of prevention is better than a 

 pound of cure." When young apple-trees are purchased from ths 

 nursery, it will always pay well, in the northern parts of Illinois, to 

 look them carefully over, and scrape off with a knife any scales of the 

 Oyster-shell species that may be found on them. In the extreme 

 southern parts of the State, this need not be done; for, as already 

 shown, the Oyster-shell Bark-louse does not like the climate of that 

 region and perishes if it is imported there. Recollect tliat every full- 

 grown scale is a female full of eggs, and that the eggs average over 

 50 in number. There are absolutely no males in this crowd, to lessen 

 the number of fruitful individuals. "Always plant a clean tree," is 

 Dr. Mygatt's advice; and this advice of his is indisputably excellent. 

 But unfortunately fruit-growers often wait till it is too late to fight 

 the foe to advantage, and in the hurry and press of business the homely 

 old adage is apt to be forgotten, that "a stitch in time saves nine." 



Dr. James Weed, of Muscatine, Iowa, believes that this Bark- 

 louse was almost entirely extirpated in his neighborhood by the in- 

 tense cold — 27 degrees below zero — of the winter of 1855 — 6. From 

 the fact already twice stated, that it is a northern species, intolerant 

 of a high summer temperature, I strongly incline to believe that there 

 must be some mistake here. In the Prairie Farmer for October 39, 

 186-1, J. C. Plurnb, of Madison, Wisconsin, writes that the cold win- 

 ter of 1863 — 4 had effected no diminution of the numbers of the Bark- 

 lice, even in that higli latitude. 



As to what is a very current opinion amongst many of our most 

 intelligent fruit-growers, namely, that it is only diseased, unhealthy, 

 and badly-cultivated trees that suffer materially from Bark-lice, I am 

 satisfied that this is an error. My own trees grow in garden soil, dug 

 originally two spit deep, with a porous gravelly subsoil two or three 

 feet below the surface, manured moderately every year with old thor- 

 oughly rotten cow manure, and cultivated through the summer; and 

 the chief difficulty that I have with them is, that they grow too ex- 

 uberantly and run too much to wood. Yet in spite of palliatives 

 applied from time to time, and in spite of my little friends the Mites, 

 the Bark-lice are steadily gaining on me ; and unless I make a vigor- 

 ous onslaught on them before long, they will probably in the end 

 overrun all my trees. The truth seems to be, that, after a certain 

 number of years, the Mites and Insects that prey upon the Bark-lice 

 become so numerous as to check them up permanently. And thus we 

 can account for the notorious fact that in those northern regions. 



