Dec. 1895.] 



INJURIOUS INSECTS AND FUNGI. 



317 



Canker {Nectria ditissima). 

 Fig. 1. 



A. Piece of apple-tree affected by Nectria ditissima. 



B. Section of branch with Nectria upon it. 



C. Bark, with Nectria, x 4. 



D. Nectria with crimson perithecia, showing orifices from which spores 



emerge, x 40. 



E. Asci from perithecia, each ascus with 8 spores, x 400. 



F. Spore, uniseptate, x 1,000. 



It is customary with fruit growers to style the various 

 disorders which affect and kill branches and boughs of apple- 

 trees " canker." Injuries from frost, hail, improper and excessive 

 pruning, and from insects, such as the Woolly Aphis and species 

 •o^ Lachiius, all come under this common appellation. It is the 



