68 THE REPORT OF THE No. 19 



Remedies. 



Except in towns there is very little need of using any remedy be- 

 cause parasites keep the scale well in check and, as mentioned above, it is 

 seldom bad many years in succession. In towns, await the hatching of the 

 young, and shortly afterwards prune severely, and where valuable trees are 

 attacked spray these thoroughly with kerosene emulsion, flour kerosene or 

 whale-oil soap. More than one spraying will probably be necessary. 



The Oyster-shell Scale, Lepidosaphes ulmi, (Linn.) Fig. 25. 



The Oyster-shell scale is found in almost every district in Ontario, and is 

 doing more injury to the fruit trees of the province as a whole than any other 

 scale. 



The scale can easily be recognized even without the aid of a lens. It is 

 2.5-4 mm. long, and .75-1 mm. wide in the broadest part, tapers toward the 

 the end, is shaped like a diminutive oyster-shell, and closely resembles in 

 color the bark on which it is found. The small end, or exuvia, is usually 

 much lighter in color than the rest. The male scale differs from the female 

 chiefly in being considerably smaller and broader in proportion to its length. 



It passes the winter in the e^g stage, from 20-100 eggs being concealed 

 under the covering of a single scale. The eggs hatch about the first week 

 in June. The tiny, white, young scale insects run about for a day or two on 

 the bark or leaves and then insert their sucking tubes in some chosen spot 

 from which they never move during the rest of their life. There is only 

 one brood in a season, but even so, the scales increase very rapidly where no 

 attempt is made to keep them in check. Badly infested trees become much 

 weakened and often die. 



Not only does this scale attack apple, pear, plum, and cherry trees, but 

 it also attacks currants, gooseberries, rose bushes, spiraeas, lilacs, and num- 

 erous shade and forest trees, such as the mountain-ash, hawthorn, red-osier 

 dogwood, black and white ash, American aspen, prickly ash, mulberry, and 

 horse-chestnut. 



Remedies. 



There are several remedies that can be used with success in combating 

 it: — 



(1) Spray with kerosene emulsion, flour kerosene, or whale-oil soap dur- 

 ing June as soon as all the eggs seem ^o have hatched. This date can easily 

 be ascertained by examining carefully, even with the naked eye, a few infested 

 blanches. These remedies are the most popular. 



(2) The lime-sulphur wash. This remedy, though not so popular as 

 No. 1, has given excellent results when well made and carefully put on late 

 in the spring when the buds are well swollen or are opening. 



(3) Whitewash. The trees must be sprayed twice, with an interval of 

 a few days between, with whitewash. This should be done as soon as the 

 leaves fall in the autumn. Use 1 to 2 lbs. lime to 1 gal. water. 



Parasites. — The most common parasites are : (1) A tiny little mite, probably 

 Tyroglyphus maZws, that preys both upon the adult and the eggs; (2) a small, 

 yellowish chalcid fly, probably Aphelinus mytilaspidis, Le Baron, the larva 

 of which preys upon the eggs (scales perforated by small, round holes have 

 been parasitised by this kind of insect) ; (3) certain species of ladybird beetles, 

 especially the twice-stabbed lady beetle (Chilocorus hivulnerus) Muls. This 

 year we found a pink fungus attacking the young scales, and on a mountain 

 ash tree, in Toronto, which was covered with scales, the pink fungus para- 

 sitised and killed nearly all the scales on the tree. (See Plate D. Fig. 6.). 



