INJURIOUSNESS OF WEEDS 677 



Charlock and other Crucifers "1 Diamond-Back Moth (Plutella mac- 



ulipennis) 



Celery Fly (Acidia heraclei) 



\ Dial 

 Prickly saltwort (Salsola kali) j ulipennis) 



Thistles, and the Cotton Thistle") 



Stem Eelworm (Tylenchus devas- 

 tatrix) (not an insect) 



(Onopordon Acanthium) j 



Hops, Yorkshire Fog, Poa annua, 

 Daisy, Shepherd's Purse, Spurrey, 

 Buttercup, Cornflower, Sow This- 

 tle, Black Bindweed (Polygonum 

 Convolvulus) and Plantain 



NI i h rd ha T b S isUe e S I : ba G e o•ofe1„ a ot• "andl ^«B»* <"*"*»■ 

 many other plants J ' 



Shepherd's Purse, Winter Cress, \ Cabbage Root Fly (Phoroia bras- 

 Hedge Mustard J sicae) 



Various Grasses } Frit Fly (Oscinis frit) 



Docks, Goosefoot, and some other ") _ .,.,,.. . . x 



wee( j s >■ Bean Aphis (Aphis rumicis) 



} Ghost or Otter Moth (Hepialus 

 lupuli) 



7. WEEDS ARE INJURIOUS BECAUSE THEY HARBOR PARA- 

 SITIC FUNGI. 



Long and Percival, in "Common Weeds of the Farm and Gar- 

 den," have the following table of fungus diseases that affect va- 

 rious weeds : 



Weed "host." Disease. 



iFinger-and-toe of turnips (Plasmodio- 

 phora orassicae Wor.) 

 Peronospora parasitica De Bary 



"I White Root-rot (Rosellinia necatrix 

 ■m • « Prill.) 



Many species r Sclerotium Disease (Sclerotinia sclerotir 



j orum Mass.) 



Wild Barley (Hordeum mur* "l Blindness in Barley and Oats (Helmintho- 

 inum) j sporium gramineum Erikss.) 



Shepherd's Purse and other"! White Rust of Cabbages (Cystopus can- 

 Crucifers j" didus Lev.) 



Many species } Y %u\) Root - rot (Rhizoctonda violacea 



Agrostis canina L., and other"! Reed-mace Fungus (Epichloe typhina 

 grasses j* Tul.) 



