42 



to be infested with red spider. Eggs of the mite were found in 

 abundance at the eyes of most of the specimens. Very few living 

 mites were seen. 



The Beure Bosc pear was manifestly infested with the spider, but 

 not so many eggs were to be found as on the apples. On the Butter 

 pear no traces of the mites were to be seen, although the deformities 

 were the same as in the case of the other varieties. 



So also with regard to the quince. The deformities were identical 

 in form, but on the few specimens sent no definite traces of mites were 

 seen. 



All the above specimens came from the same orchard. The 

 number of eggs in the eye of an apple reached two to three score in 

 the worst cases. They were present in every apple examined. 



Shot-hole Stigmonose. 



The so-called shot-hole disease is one of the few serious diseases of 

 the apricot. This fruit tree is for the most part very vigorous with 

 us, if only it can be kept free from shot-hole. Not infrequently, how- 

 ever, this disease makes sad havoc with the crop. Every season 

 specimens are forwarded to me representing badly diseased crops that 

 have been a total or partial failure. The disease is almost universally 

 present in a mild form, and only awaits the right conditions to make 

 itself felt in the shape of obvious money loss. 



For some time I have felt that . our theory of this disease did not 

 account for all the facts. 



The disease is commonly set down as of fungus origin, and remedies 

 have been proposed on this basis, and these remedies have been more 

 or less successful. 



There can be no doubt that certain fungi do cause the so-called shot- 

 holes to appear in the leaves of the apricot and other stone-fruit trees. 

 The fungus Phyllosticta circumcissa is that to which shot-hole used to 

 be referred. 1 have described another form that is sometimes seen 

 on the margin of shot-holes and of scabs on the fruit. Professor 

 McAlpine has recently described quite a number of other shot-hole 

 fungi. 



I have seen numerous cases of this kind, however, that yielded, 

 after the most careful examination, no traces of a vegetable parasite 

 of any kind. 



In April, 1901, I began a systematic examination of the shot-holes 

 of certain apricot trees, with the result of proving that on mature leaves 

 the disease was generally stationary. Week after week the holes 

 remained the same in size, and new holes did not appear. The obser- 

 vations extended over several weeks. No traces of a vegetable parasite 

 were seen. The opening of the following spring was awaited with much 

 interest, as this would give an opportunity to extend the observations. 



A continuance of similar observations proved that the shot-holes 

 appeared on very young leaves, leaves that were still in the early stages 

 of growth, and that they were preceded by very minute decoloured 

 areas, in which, however, no vegetable parasite could be discovered. 

 The holes in the young leaves increased in size with the growth of the 



