io8 Second Reptwf on Econoniic Zoology, 



FUNGOID PESTS MISTAKEN EOR INSECT DAMAGE. 

 Canker in Fruit-trees. 



The common disease " canker " {Nectria ditissima), in apple and 

 other fruit trees, has recently been much on the increase, and several 

 peculiar symptoms do not seem to be known by fruit-growers, or 

 recorded in the literature. The symptoms so much resemble insect 

 work that it is advisable to point them out here. The cases recorded 

 were referred to the chief authority on the fungoid diseases of fruit 

 trees, Professor Percival, Director of the Agricultural Department of 

 Pleading College. Mr. Neame's letter, reproduced here, gives an 

 excellent idea of the symptoms : — " After the bud has started 

 growing, it withers off and dies. This complaint seems to occur on 

 spurs. Tlie wood dies back for a small area around each spur 

 affected. A few spurs were affected last year, still more this ; three 

 trees of ' Strumer Pippins ' are affected at the corner of a small plot 

 of thirty trees or so, those adjoining not. In another plot several 

 trees are touched ; it is not, I think, due to the frost. The sap fails 

 right round the branch when a spur is attacked. The infection 

 of the twigs seems to have taken place shortly after the blossoms 

 were fully out." 



There is a very decided resemblance between this attack of 

 "canker" and the working of the Pith Moth; but a casual 

 examination will show the presence of the caterpillar in the shoot 

 when Pith Moth is present. 



Eegarding the " canker," Professor Percival advises as follows : — - 



It is important that all cankered shoots should be cut off and 

 l)urnt, especially in young plantations. In old trees the cankered 

 branches are often large, and it is difficult to recommend wholesale 

 amputation in these cases ; but, even in these cases, it is advisable to 

 get rid of the most useless branches ; they are a source of infection. 



Some varieties are much more liable to the disease than others, 

 and these varieties I have found are sorts which ripen wood very late 

 in the season, and hence are liable to be damaged by frost during the 

 winter. 



In valuable trees it is advisable to cut away the dead cankered 

 portions of the bark to healthy wood and bark, and paint the wound 

 with Stockholm tar. But when the dead patch encircles, or nearly 

 encircles the brancli, cut it off altogether and burn, as a proper circu- 

 lation of saj) in tlie branch cannot go on long, and death takes place 

 very soon after growth has beuun in summer. 



