234 FARM FRIENDS AND FARM FOES 



4. This mycelium soon produces certain swellings or 



pustules called aecidia from which spring spores or 

 aecidiospores are developed. 



5. These aecidiospores spread the disease and start more 



mycelium. 



6. In summer the mycelium produces other pustules 



from which the orange-colored summer spores or 

 uredospores are developed. 



7. These uredospores spread the disease far and wide, 



starting more mycelium from which more uredo- 

 spores are developed. 



8. In autumn the mycelium in the tissues produces black 



pustules from which the winter spores or teleuto- 

 spores are developed, thus completing the yearly 

 cycle. 



Even in a slightly infested asparagus field there are mil- 

 lions of teleutospores each spring. If each of these devel- 

 ops eight sporidia, there are of course enormous numbers of 

 the latter produced. These sporidia are short-lived, how- 

 ever, and each must soon find a living asparagus plant if it 

 is to start the disease anew. In established fields the 

 asparagus is cut and carried off almost as soon as it comes 

 up. Consequently, there is little chance for the rust to get 

 a foothold there. The asparagus plants upon which the 

 disease grows in spring are generally chance seedlings in 

 neglected corners or those newly planted fields in which 

 cutting has not been begun. It is important, therefore, to 

 destroy wild asparagus plants, for they help to tide the 

 disease over the weeks of spring. 



CLOVER RUST 



The Clover Rust is similar in its yearly history to the 

 Asparagus Rust. It has the same three kinds of spores 



