IV 



CAUSES OF PLANT DISEASES 73 



who has described a large number of species of nematodes, 

 expressed the opinion that the Australian species, 

 which he named Tylenchus arenarius, was identical 

 with the species previously reported from the United 

 States. In 1909 the same author reported Heterodera 

 radicicola on the sugar-cane in Hawaii. It will be 

 readily seen that our present knowledge of the subject 

 is in a decidedly chaotic condition. However, it is safe 

 to say that nematode diseases are widely distributed 

 throughout the torrid and the two .temperate zones. 

 Dr. Ernst A. Bessey, who has recently made extensive 

 studies upon this subject has sent me an unpublished 

 list of more than three hundred plants on which the 

 disease is known to occur. From a number of published 

 lists which are before me, I have made the following 

 incomplete list which will indicate the wide range of 

 host plants which suffer to a greater or less degree 

 from this pest : 



Amygdalus persica 



Ficus carica 



Vitis vinifera (several varieties) 



Thea sineusis 



Solarium tuberosum 



,, melongenum 

 Lycopersicum esculentum 

 Gossypium herbaceum 

 Hibiscus esculentus 

 Cassia obtusifolia 

 Dolichos Catjang 

 Phaseolus vulgaris 

 Lespedeza striata 

 Melilotus alba 

 Ipomea sp. (several) 

 Phytolacca decandra 

 Helianthus annuus 

 Citrullus vulgaris 

 Beta vulgaris 

 Amaranthus retroflexus 



Peach . 



Fig 



Grape 



Tea 



Potato . 



Egg-plant 



Tomato 



Cotton . 



Okra 



Coffee-weed 



Cow pea . 



Bean 



Japan Clover . 



Sweet Clover . 



Morning Glory 



Poke Berry 



Sunflower 



Water-melon . 



Beet 



Careless Weed 



Corn 



Cabbage . 



Turnip . 



Kutabaga 



Parsnip . 



Lettuce . 



Zea Mays 

 Brassica oleracea 



rapa 



,, campestris rutabaga 

 Pastinaca sativa 

 Lactuca sativa 



