Influence of Compaction and Subsoil Tillage on Soil Conditions and Pink Eye
Fluorescent bacteria were isolated frequently from discolored xylem and parenchyma of Maine-grown potato tubers that had the red-xylem disease, pink eye, or infected bruise cracks. Isolates were identified as strains ofPseudomonas fluorescens. Some strains produced softening of potato slices and a progressive black rot inside tubers, whereas other strains produced neither; the former did not lose their pathogenicity in the course of several years’ maintenance in broth. In the field, pink eye, associated with Verticillium wilt, was correlated positively with soil moisture. Black rot was more active at 35° F. than at 50° or 70°. Infection in bruise cracks was less frequent in tubers dipped in solutions of Agri-mycin, sodium hypochlorite or Phygon previous to bruising than in comparable untreated, noninoculated tubers. Stolon and tuber stem-end inoculation induced red-xylem symptoms. Tuber eye-end inoculation induced pink-eye.