254 



THE CANADIAN HORTICULTURIST. 



The Plum Scale. 



1 1 57. Sir, — I enclose you two 

 small pieces of an apple tree from 

 Mr. G. L. Hubbs, Picton, P. O., with 

 scale, or insect, on the bark. A red 

 insect seems to come from the scale, 

 and when the scale is removed it 

 leaves a white spot on the bark. Will 

 you kindly give me any information 

 you can about it ? 



Picton. Walter T. Ross. 



We have frequently had sam- 

 ples of this scale sent into this 

 office, and it is quite common, 

 both in this province and in New 

 York state. It is so large as to 

 be easily fought, either by scrap- 

 ing off and burning, or by spray- 

 ing with whale oil soap. The 

 following is from our volume for 

 September, 1894, with the accom- 

 panying illustration : 



This illustration is from a pho- 

 tograph of an infested branch of 

 the Bradshaw plum. On the twig 

 at the left are seen scars show- 

 ing where some of the scales have 

 been removed. The actual length 

 and width of a full-grown scale 

 is indicated by the cross lines in 

 the illustration. The dimensions 

 are usually about five millimeters 

 by four — that is to say, abont 

 seven thirty-seconds by five thirty- 

 seconds of an inch. 



At the present writing, June 20th, the 

 scales are filled with a whiteish powder, 

 which, examined with a lens, proves to be 

 composed of eggs. The young lice, which 

 are produced from the eggs m the spring, 

 had already issued from the old scales this 

 season about May loth, when my attention 

 was first called to the insect. The branches 

 were then covered with a sticky substance 

 like honey-dew, evidently secreted by the 

 young insects. On leaving the old scale 

 they crawl over the branches till, finding a 

 convenient location, they attach themselves 

 to the bark. They seem to prefer a location 



Fig. 1833. 



-Branch of Plum Infested with Scale, 

 Lecanium Cerasifex. 



on the under side of the limbs. At first they 

 whitish, or nearly transparent, but gradually 

 assume the dark reddish brown color of the 

 mature insect. 



Mr. L. O. Howard, the United States 

 Entomologist, o whom specimens were 

 submitted for identification, states that it is 

 a somewhat rare species known as Lecanium 

 cerasifex. He adv^ocates spraying with di- 

 lute kerosene emulsion when the young in- 

 sects first appear in the spring. The scales 

 are soft and can easily be brushed or scraped 

 from the larger branches. 



