HETERODERA RAD1CICOLA. 413 



Cajanus indicus — dal, or pigeon pea. 



( 'alendula officinalis — marigold. 



Cannabis indica — "dagga." 



( 'apsicum annuum — chillies. 



( 'arica papaya — pawpaw. 



Chenopodium sp. 



( ' in a mis satirus — cucumber. 



( 'ucurbita pepo — pumpkin. 



Dahlia variabilis — dahlia. 



Datura stramonium — "stinkblaar." 



Dane us carota — carrot. 



Diantli us caryophyllus — carnation. 



Fagopyrum esculent um — buckwheat. 



Ficus raric us— edible fig. 



Helianth us annuum —sunflower. 



Ipomoea batatas — sweet potato. 



Lactuca sativa — lettuce. 



Lagenaria vulgaris — calabash. 



Lupin us sp. — lupin. 



Lycopersicon esculentium — tomato 



Lygustrum vulgarum — priveF. 



Medicago sa t iva — lucerne . 



Nicotiana tabacum — tobacco. 



Pastinacea sativa — parsnip. 



Phase ol us vulgaris — bean. 



Petunia hybrida — petunia. 



1'ii I or sp. — perennial phlox. 



Physalis peruviana — Cape Gooseberry. 



Pentstemon wrightii — Pentstemon. 



Pi sum sativum — pea. 



Prun us armeniaca — apricot. 



I'm n us domestica — plum. 



/'run us persica — peach. 



Iiiiiuus communis — castor-oil tree. 



Rosa setigera — rose. 



Solan u m a uric ula t u m . 



Solatium nigrum — nightshade. 



Solan um tuberosum — potato. 



Vitis vini f era — grape vine. 



Zea mais — mealie cr maize. 



Conditions Favouring Heterodera radicicola. 



It has been noted that heavily infested plants, containing 

 numerous Heterodera, often occur on loose, sandy soil, well supplied 

 with water, so that the subsoil is constantly moist. A heavy 

 loamy-clay soil does not appear to be favourable to the parasite, 

 and plants growing on such a soil would, consequently, be free 

 from the pest to a large extent. 



Geographical Distribution of Heterodera. 



Heterodera radicicola has a world-wide distribution. The 

 fact of its not having been reported from Rhodesia and other 



