BACTERIAL ROTTING OF APPLE FRUIT

Three bacterial isolates obtained from a rotten apple were found to produce actively spreading firm brown rots when stab‐inoculated into Bramley's Seedling apples, but bacteria were not found at the front of the rot. One isolate was a capsulated, non‐motile, non‐fluorescent, Gram‐negative rod apparently not described previously. The name proposed for the isolate is Pseudomonas pomi. The other two isolates were the same and were non‐capsulated, non‐fluorescent, Gram‐negative motile rods, usually with two polar flagella, and were considered to be identical with Ps. melophthora Allen & Riker (Allen & Riker, 1932). The three isolates grew on media at pH 5.0 and in apples with juice of pH 3.5. For each isolate the square of the distance of the front of the rot from the point of inoculation of apples, was found to be directly proportional to the time after inoculation. The isolates were able to invade fruit at the stalk and eye ends and where the skin had been pricked. No apparent infection followed spraying leafy shoots or flowers of Bramley's Seedling trees with bacterial suspensions and there was no visible reaction after hypodermic inoculation of bacterial suspensions into apple shoots.