74 DISEASES OF TROPICAL PLANTS OH. 



Shepherd's Purse . Capsella bursa-pastoris 



Blackberry . . Rubus villosus 



Dog Fennel . . Eupatorium foeniculaceum 



Cypress Vine . . Quamoclit vulgaris 



Purslane . . . Portulaca oleracea 



Cassava . . . Jatropha manihot 



Pea-nut . . . Arachis hypogaea 



Petunia . . . Petunia sp. 



Begonia . . . Begonia sp. 



Dahlia . . . Dahlia sp. 



Citrus Fruits . . Citrus aurantium, etc. 



Plum . . . -Prunus myrobalanus 



. . . ,, domesticus 



Mulberry . . Morus sp. 



Walnut . . . Juglans cinerea 



Pecan . . . Carya olivaeformis 



Almond . . . Prunus communis 



Tobacco . . . Nicotiana tabacum 



Rose . . Rosa sp. 



Violet . . Viola sp. 



Sugar-cane . . Saccharum officinal e 



Banana . . . Musa sp. 



Although the present state of our knowledge of this 

 subject is decidedly chaotic and confusing, it is not 

 impossible to give a general and somewhat popular 

 discussion. The disease is not serious upon all species 

 of plants, but it is, no doubt, injurious to some extent 

 in all cases. In many instances the plants show no 

 external evidences whatever of the presence of the 

 nematodes, while in others the plants become unhealthy 

 and die with no apparent cause. However, an examin- 

 ation of the roots of the plants will reveal a greater or 

 less number of galls, which if sectioned and examined 

 under a microscope will be found to contain many of 

 these little worms. The number and character of the 

 galls varies largely with the host plants and the number 

 of worms in the soil. However, the galls on plants 

 with fleshy roots like the beet are frequently very large, 

 while the galls on the plants with fibrous roots are 

 much smaller. In some instances the galls are so small 

 as to be scarcely noticeable. 



It must be kept in mind that galls are frequently 

 produced by other organisms. One of the most common 



