Thf: Canadian Horticulturist. 355 



they would sell much sooner. The value is not certain, but very nearly as 

 much. 



C. — Cultivation ? 

 Plant in old, tilled, clean land. For amateurs it is safer to buy two year-old 

 seedlings, as the difference in cost will not be so great as the extra cost of the 

 cultivation of small seedlings. Plant them four feet apart each way, and keep 

 the weeds down thoroughly for three years. 



D. — Soils fiest suited ? 



Sandy loam is the best soil, where easily worked with a cultivator. 



£. — Ifo7v many trees to the acre ? 



At four feet apart there would be about 2,700 trees to the acre. 



Except for experienced planters, the seedlings, which can be got from 

 wholesale nurseries in the United State at from $r.oo to $8.00 per thousand, are 

 much more satisfactory than planting tree seeds, and the cost of handling and 

 transplanting in the small way, as well as the trouble of keeping the very 

 small trees from the pressure of the weeds, will be more than the nursery prices. 



PEAR LEAF BLISTER MITE. 



SiK, — You will find enclosed some pear leaves which I sprayed with Paris green twice 

 this season. Did this cause their turning brown, or is it a leaf blight ? 



Gkorge H. Nixon, Hyde Pari-, Ont. 



Reply by Prof. James Fletcher, Entomologist, Experimental Farm, Ottawa. 



The leaves of pear are, as you suggest, badly infested by the pear leaf blister 

 mite (Phytoptus pyri), which is an extremely small, elongated mite, that forms 

 blisters like galls on the leaves. In each of these galls there are several of the 

 mites. There is a small hole in the centre of each gall, through which the little 

 creatures make their exit. The eggs are laid by the females inside the galls, and 

 hatch there. The young mites remain there for some time and then come out 

 and work their way into the tissue of the leaf at some uninjured spot. They 

 increase rapidly, and eventually do much injury to the tree. The mites live 

 within the galls until the time the leaves fall in the autumn, when most of them 

 migrate to the leaf-buds at the ends of the twigs, where they pass the winter. 



This insect is one of the most troublesome to combat. Prof. J. H. Com- 

 stock (Cornell University Bulletin, No. 23) has written the most extensive article 

 on this continent, and in Australia it has been treated of by Mr. C. French, in 

 his " Handbook of Destructive Insects of Victoria." 



Probably the best remedies are close pruning in winter or early spring, fol- 

 lowed by a thorough syringing with kerosene emulsion. An effort should also 

 be made to burn all the leaves which fall in autumn. I may mention that the 



