. Journal of Agricultural Research. f the Society ofAmerican Bacteriologists the name of this clover organism would be Pseudomonas trifoliorum, n. sp. 60097—23 2 488 Journal of Agricultural Research Vol. XXV, No. li OVERWINTERING AND DISSEMINATION No experimental evidence on the overwintering and disseminationof Bacterium trijoliorum is at hand. The field observations, however,during the several seasons in which the disease has been investigatedshow that it recurs annually in the same general areas in the cloverfields and on the same small groups of plants in meadows and old clover f
. Journal of Agricultural Research. f the Society ofAmerican Bacteriologists the name of this clover organism would be Pseudomonas trifoliorum, n. sp. 60097—23 2 488 Journal of Agricultural Research Vol. XXV, No. li OVERWINTERING AND DISSEMINATION No experimental evidence on the overwintering and disseminationof Bacterium trijoliorum is at hand. The field observations, however,during the several seasons in which the disease has been investigatedshow that it recurs annually in the same general areas in the cloverfields and on the same small groups of plants in meadows and old clover field at Madison was observed almost daily during April,May, and June, 1920. The disease appeared, with the advent of warmweather in April, upon the young leaves soon after they had , no doubt, fallen diseased leaves harbored the parasite duringwibter and it spread from them to the new leaves. The disease wasvery much in evidence during May, and by blossoming time every leafon a plant might be conspicuously spotted. ;. Fig. 3.—Diagram of two clover leaves in which insect injuries (Phytonomus punctaius) and the bacteriallesions (Bacterium trifoliorum) are associated. In the leaf at the left, the lesions were youns; and water-soaked and apparently had originated at the insect puncture. In the leaf at the right, the insects may,at least in some places, have eaten out the invaded tissue. In any case, the water-soaked margins indi-cated that the invasion was still progressing. (Drawing by Charles Drechsler.) The fact that the disease under favorable conditions involves theplant so generally makes it highly probable that the floral parts mightbecome infected. Lesions have not been observed, however, on thefloral organs, but they are of common occurrence on the flower though flowers are not involved, there would be ample opportunityfor the seed to become contaminated either while yet in the field or duringharvesting or threshing. The initial infections in
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