108 Capskl Bugs cuid Apples 



in England and this paper is intended partly to throw more light on this 

 question — though it has for its primary object the attraction of more 

 attention to the subject at large, since the actual loss which may result 

 from the attacks of Capsids is very serious. 



As in the case of most plant bugs {L. pratensis is sometimes an 

 exception) the primary cause of the damage is a puncture made by the 

 bug in feeding. The juices of the plant are drawn up through this 

 wound and either on account of the direct loss of sap or possibly from 

 the injection of some irritant poison the surrounding tissues are more or 

 less injured, the extent of the injury varying with the condition and 

 portion of the plant attacked. In the case of apples the injury takes 

 place very early in the season, probably before the blossom opens, when 

 the tissues of the developing fruit and foliage are soft and in a state 

 of rapid growth. The bugs responsible have then but recently been 

 hatched and are very small ; they appear to feed equally on the 

 young fruit, foliage and young shoots, all of which suffer to some 

 extent, though the injury to the fruit is the serious feature. The 

 puncture of the bug appears to cause a definite check to the sur- 

 rounding tissues so that, as the fruit grows, some parts develop more 

 rapidly than others and a badly shaped, distorted apple is formed. When 

 the check is very severe all growth ceases near the wound and as the 

 remainder of the fruit swells rapidly a crack appears and may extend 

 the whole length of the apple. A further feature often present is a 

 more or less extensive discolouration or " russetting," which seems to 

 arise from the abnormal development of the damaged cuticle. Finally 

 the surface of the fruit may show a number of small pimples which so 

 far as is known at present are the result of the unhealthy healing of the 

 punctures. In the young fruit the actual puncture is readily seen but 

 later it becomes obliterated and there is not as a rule any discolouration 

 in the flesh of the apple as described by Caesar in the Canadian attack. 

 It will be noticed that some of these forms of injury may also appear 

 from other causes and are not infrequently attributed to some climatic 

 action, as for instance to cold winds or excessive moisture. Although 

 it seems probable that Capsid injury is more common than is generally 

 supposed, at the same time it is obvious that all checks to the developing 

 tissues of the fruit would be likely to produce very similar results so 

 far as the mature fruit is concerned. 



The injury to the foliage is perhaps more definitely diagnostic of 

 an insect attack. As in the case of the fruit the puncture afTects the 

 surrounding tissues so that an attacked leaf shows numerous brown 



