ROSES.— INSECTS AND DISEASES. 



179 



Stem-boring Saw-fly. — The larva of this is quite distinct. It is a much smaller 

 maggot than the preceding, and when ready to pass into the pupa state burrows into 

 the pith of young shoots, also taking advantage of any injury or crevice. The shoots 

 die at the point, or if the maggot has penetrated lower down, the growth above droops 

 over and succumbs. The same maggot eats into the pith of briar stems used for 

 standard roses, starting from the top, and often killing the briar below the part 

 budded with roses. 



Very destructive, indeed, are a few of these flies, as a single insect will deposit an 

 egg in the piths of many briars. The flies may be seen during early morning and 

 evening, flitting from plant to plant, and with a little alertness a number may be killed 

 at this time. With briars it is always well to smear a little grafting-wax over the 

 top, also at the end of budded branches, when trimmed back in the spring. Two parts 

 of pitch, one of resin, and two of a composite or tallow candle, melted together, 

 make an excellent and cheap wax for the purpose. Apply in a lukewarm state. We 

 now pass to a few maladies. 



Mildew. — This is the worst and most prevalent enemy of the rose. A dry 

 atmosphere, a chill after a spell of hot weather, in fact any great atmospheric change, 

 will almost invariably bring on mildew. We cannot avoid it in the open, but a judicious 

 syringing directly a great change is noticed will have a beneficial effect. Under glass, 

 however, there is little excuse for its presence to any alarming extent, as here we have 

 the atmosphere comparatively under control by care in heating and ventilation. 

 Avoid the conditions favourable to the growth of mildew, which is a parasite and fungus, 

 and then resort to the precautionary measures named under the heading, "Recipes." 



Eed Rust and Orange Fungus. — Rust is an early condition of mildew within the 

 plant, and, on reaching maturity, bursts through the epidermis. They are increased 

 by spores, and affected leaves should be gathered and burned. Fortunately, they 

 seldom become very troublesome until late in the season, and then chiefly upon the 

 summer-flowering roses that are of little further use the same, season. The leaves turn 

 brown and spotted, have the appearance of premature ripening, and soon fall, leaving 

 the plant as bare as during winter, while those not attacked are still in full growth and 

 health. 



Canker. — This affection is not often found except upon Marechal Niel, William 

 Allen Richardson, and a few more very strong growers. Occasionally an injured 

 plant will develop it, and it is more frequent when the rose-growth foster or stock 



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