PREVENTION AND ERADICATION OF WEEDS 71 



and so destroying their power of germination. The seeds of 

 bindweed, gorse, and some species of wild pea are often so 

 badly attacked that it is difficult to find an uninjured seed. 

 At best this method would be of limited value, some of the 

 worst weeds, such as wild oat (Avena fatua), being apparently 

 immune from the attacks of any kind of parasite, whether 

 animal or fungus. 



