Termohlen proved that corky root was caused by a fungus, which was readily isolated and cultivated. The fungus did not sporulate but several isolates made sclerotia on agar. Its features on nutrient medium were described. The fungus had not been named. Isolates varied greatly in pathogenicity. The pathogen remained in the soil as myceliurn in root debris and possibly also as sclerotia.Besides the tomato several other Solanaceae were susceptible to corky root. From Physochlaena orientalis and cucumber the pathogen could be isolated; these plants, however, did not show any symptoms and were thus carriers. Rotation experiments with cucumber and some other crops alternating with tomato had but little effect on the inoculum potential of the soilControl was by steaming the soil or disinfecting it with chloropicrin. DD had no effect.All cultivated varieties of tomato so far tested were susceptible. Lycopersicum glandulosum, L. peruvianum and L. hirsutum were highly resistant. Crosses to obtain resistant tomato varieties were made. The first filial generation of the crossing L. esculentum with L . hirsutum was resistant and suitable as a root stock for the tomato but it was susceptible to eelworm infestation.

Termohlen proved that corky root was caused by a fungus, which was readily isolated and cultivated. The fungus did not sporulate but several isolates made sclerotia on agar. Its features on nutrient medium were described. The fungus had not been named. Isolates varied greatly in pathogenicity. The pathogen remained in the soil as myceliurn in root debris and possibly also as sclerotia.Besides the tomato several other Solanaceae were susceptible to corky root. From Physochlaena orientalis and cucumber the pathogen could be isolated; these plants, however, did not show any symptoms and were thus carriers. Rotation experiments with cucumber and some other crops alternating with tomato had but little effect on the inoculum potential of the soilControl was by steaming the soil or disinfecting it with chloropicrin. DD had no effect.All cultivated varieties of tomato so far tested were susceptible. Lycopersicum glandulosum, L. peruvianum and L. hirsutum were highly resistant. Crosses to obtain resistant tomato varieties were made. The first filial generation of the crossing L. esculentum with L . hirsutum was resistant and suitable as a root stock for the tomato but it was susceptible to eelworm infestation.

Maxillectomized hornworms were reared from the beginning of the 4th instar to adulthood on four species of non-solanaceous plants which are not fed upon by intact larvae. Growth and reproduction were normal on Taraxacum, reasonably good on Arctium, but poor on Verbascum and Catalpa. Poor growth was related to a low rate of feeding which may have been due to the effects of non-nutrient feeding deterrents. But the possibility of anorexia caused by a nutritional deficiency or imbalance has not been eliminated. Tomato, Taraxacum and Arctium were converted to body matter with comparable efficiency. Verbascum and Catalpa were converted much less efficiently.