244 ANNUAL REPORT OF THE Off. Doc. 



wherever the scale oecnrs. and always takes a certain percentage 

 of specimens. The female lays a single egg in a scale insect and the 

 {)arasite larva develoi)s and conies to maturity within the body of its 

 host. Other lady-birds feed on the crawling larvae, and some other 

 j)redatory species pick them up occasionally; but nothing is really 

 effective as a check. 



In 181)0, the writer introduced into New Jersey a large number of 

 lady-birds from California. All of them died. In 18I)S, he intro- 

 duced the Ch'docorus simllls from Japan; but this also died. 



Other natural checks, are heavy rains in the breeding season and 

 diseases. The writer has seen hundreds of larvae washed down and 

 battered to death by a heavy summer shower, and knows from ob- 

 servation that damp cold weather is fatal to many of the crawling 

 stage. 



Disease plays an important part in the multiplication of the 

 species, and its percentage affects very materially the rate of in- 

 crease. On some trees, in some years, the writer has found ninety 

 per cent, of the scales dead from some unknown disease; but thus far 

 this has been neither isolated, studied nor propagated. Prof. Rolfs 

 found a transmissible disease in Florida, that was effective there, and 

 he succeeded in getting pure cultures. Some of the diseased scales 

 and some of the cultuies were brought into New Jersey, and on a few 

 scaly trees the disease was actually established; but it was found 

 that the climatic conditions were not favorable for its spread, and 

 while for two years the disease was active where it was established, 

 it has not extended to other trees and did not eveu control the scales 

 where it had taken hold. 



Up to the present then, we cannot in the Atlantic States, depend 

 upon natural checks for effective assistance in preventing injury from 

 the San Jose or Pernicious Scale. 



THE SCALE PROBLEM AS IT CONFRONTS THE HORTICUL- 

 TURIST. 



The presence of the pernicious scale in any orchard offers two al- 

 ternatives to the fruit grower. He must either abandon his trees or 

 he must fight the insect actively, persistently and intelligently. If 

 he has an infested peach orchard the need for action is imperative 

 or his trees will be beyond help. Other trees will last longer, but 

 as soon as the insect extends throughout the tree, the fruit will be- 



