Dec. 1895.] 



INJURIOUS INSECTS AND FUNGI. 



321 



."^ Apple-trees should be kept free from the common Apple 

 Aphis, and the Woolly Aphis, as these convey fungus spores 

 from tree to tree. In woods and plantations the cankered 

 branches should be removed from infected trees and burnt. 

 Careful foresters will examine trees that show signs of decay 

 with a pocket lens to ascertain if the Nectria ditissima is the 

 cause of the evil. 



Smut of Corn (Ustilago tritici, Persoon), 



A. "Wheat ear, natural size, destroyed by Ustilago. 



B. Glumes, twice natural size, destroyed by Ustilago. 



C. Spores of Ustilago tritici much'magnified. 



D. Spore germinating and producing conidia, much magnified. 



E. Conidia germinating, much magnified. 



Every corn-grower is familiar with the appearance of smutted 

 ears of wheat, as shown at A in the illustration, which in 



O 89185. 



