101 



The Hawthorn Hedge. 



I am of opinion that the Hawthorn hedge is a mistake in fruit- 

 growing districts unless it receives the same care as the orchards 

 themselves. 



The Hawthorn is closely related to the apple, pear, quince, and 

 some other common fruits, and in consequence the various pests of 

 these species find a convenient refuge in Hawthorn hedges. This 

 opinion is not based on a mere surmise ; I have frequently, as others 

 have done, seen the pests actually in the possession of the hedges. It 

 is said that the codlin moth can live in the Hawthorn berry, with what 

 truth I do not know from actual observation, never having seen such 

 a case myself. There are other insect pests injurious to the pomaceous 

 fruits that thrive on the Hawthorn and find a lurking place there. 



As to fungus pests, I have found several destructive pests of the 

 orchard to be common on the Hawthorn. Ripe-rot and canker fungi 

 are both very common on it. I believe it would be almost impossible 

 to find a Hawthorn hedge without these diseases. 



The edges of the leaves are frequently eaten away after the manner 

 of the pear-leaves examined and reported upon some years ago in this 

 journal. Among the debris to be scraped away from the edges of 

 such leaves may be found minute spores, which 

 appear to have originated from very small peri- 

 thecia. After lying for an hour in water the 

 spores appear in masses supported in a gelatinous 

 transparent substance, as if they had been forced 

 out from a hidden receptacle where they had been 

 previously packed away. The time of their 

 appearance is too soon after the preparation is made to admit of the 

 supposition that they have grown from a single spore or a few spores, 

 or from mycelium. 



The bark of the Hawthorn is often eaten away by a canker fungus. 

 The external and microscopic appearances are the same as on apple- 

 trees. The bark is destroyed down to the wood. 



A species of G-loeosporium was found on the Hawthorn, a descrip- 

 tion of which will be found in the notes on Ripe-rot. 



in? 



Fig. 116. Canker fungus of 

 the bark of hawthorn. 



X400 



Fig. 117. Spores of 

 Gloeosporium of the 

 hawthorn. 





Fig. 118. Spores of the Gloeosporium 

 found growing naturally on th 

 berries of the hawthorn. These ar 

 shown in the first stages of germina- 

 tion. It is not often that the spores 

 become four-parted in this manner 

 before throwing out a definite my- 

 celia thread. 



X 400 



I 

 ! 



Fig. 119. Gloeosporium, 

 found growing on the 

 fruit of hawthorn (Cra- 

 taegus). June, 1902, at 

 Killara, New South 

 Wales. 



The berries are often found covered with a blackish growth, and 

 upon removal this is found to be composed of spherical dark-coloured 



