230 



EXPERIMENTAL FARMS. 



64 VICTORIA, A. 1901 



leaves, and are said by Mr. Sirrine to be much more particular about what they eat 

 than is the case with the imported Cabbage Worm. They walk rapidly, and, if they 

 find any foreign substance on the leaves, they move off to other parts of the plant. 



The caterpillars are pale green, striped with longitudinal whitish lines. The body 

 of these caterpillars is shaped diiferently from most of the common noctuid caterpillars 

 found in gardens, in that it increases gradually from the head to the last segment, 

 where it is largest and slopes oli' abruptly. Another noticeable difference between the 

 caterpillars of the Plusias and otiier noctuid caterpillars, is the fact that they have only 

 two pairs of prolegs instead of four. There are several species of these insects, but 

 none have ever proved very troublesome in Canada. In ] 884, the Cabbage Plusia was 

 very destructive in the State of Minnesota, almost equalling the injuries of the 

 common Cabbage Worm (Pieris rapae, L.). Dr. Forbes states (111. Agr. Exp. Stn. Bull. 

 60) that the larva feeds on celery, kale, turnip, tomato, lettuce, mignonette, dandelion, 

 dock, clover, lamb's quarters, and some less common cultivated crops. It ranges 

 through the United States and occurs also in Canada. The eggs are laid upon the 

 food plants, singly or in small clusters The larva spins a gauzy cocoon among the 

 leaves. The pupa is light yellowisli brown in colour. The moths are very dark, the 

 upper wings being almost black or very dark gray, marked with small white points 

 and indistinct bands, and having a silvery U-shaped spot on the middle of the f orewing, 

 and a smaller round silvery dot close to it on the outside. There seem to be two 

 broods of this insect in Canada. 



It has proved to be a difficult matter to destroy the caterpillars of the Cabbage 

 Plusia upon cabbage and lettuce crops. Mr. F. A. Stirrine (N.Y. Agr. Exp. Stn., 

 Bull. 144) tried many experiments with remedies, and found that a soap wash con- 

 taining arsenical poisons proved the most useful. IJe speaks of this as a resin-lime 

 mixture and gives the best formula for its preparation. The estimated cost for 

 preparing and applying this remedy is $2 an acre. 



THE SAN JOSE SCALE 

 (Aspidiotus perniciosus, Comsk.). 



This insect continues to receive the Iceenest attention from practical entomologists 

 in all parts of North America, and most careful experiments have been carried out In 

 the endeavour to find any treatment which will control the scale without injuring the 



tree. At the present time crude petroleum and 

 whale-oil soaps (caustic potash fish-oil soaps) 

 seem to give the greatest promise in this direc- 

 tion. With regard to crude petroleum, more 

 experience seems to be necessary before a definite 

 recommendation can be made as to the strength 

 and manner in which it can be safely applied. 

 Mr. George E. Fisher, the chief Inspector for 

 tSan Jose Scale for the province of Ontario, has 

 experimented extensively during the past summer 

 with both of the above-mentioned materials, and 

 the results of this work, which he presented in 

 an important address before the Entomological 

 Society of Ontario, at the annual meeting in 

 November last, may be summarized as follows : — 

 AYhale-oil soap, at a strength of two pounds 

 to one gallon of warm water, killed many scales; 

 but in no case was complete success obtained, how- 

 ever carefnllj' the work might have been done. The 

 trees, nevertheless, were in most cases benefited 

 by the application. The scale was reduced to the 



Fig. 16. — San Jose Scale; apple branch 

 with scales ; large scales above at 

 left 



