Journal of agricultural research . ible todetermine the position of this organism among previously describedspecies, since it has been found to be morphologically not unlike severalof them. Its relation to the production of Citrus canker is definitelyestablished as a result of this study. Then, too, no particular difficultywould be experienced by other investigators in identifying it because of its association withCitrus canker. Inview of these facts itseems well to de-scribe it as a newspecies with the fol-lowing brief technicaldiagnosis: ^ Phoma socia, n. sp. Pycnidia irregularlydistributed,
Journal of agricultural research . ible todetermine the position of this organism among previously describedspecies, since it has been found to be morphologically not unlike severalof them. Its relation to the production of Citrus canker is definitelyestablished as a result of this study. Then, too, no particular difficultywould be experienced by other investigators in identifying it because of its association withCitrus canker. Inview of these facts itseems well to de-scribe it as a newspecies with the fol-lowing brief technicaldiagnosis: ^ Phoma socia, n. sp. Pycnidia irregularlydistributed, globose,wholly or partially em-bedded, 100 to 150M indiameter; walls thin,corky brown in color,thickened only around theostiolum, which opens centrally; conidia continuous, ellip-tical or oblong, hyalin, 9 to 12 by 3 to 4ju. Occm-s in the cankers produced by Pseudomonas citri on living leaves and branchesof Citrus trifoliata, C. nohilis, and Fortunella sp. and on living leaves, branches,and fruits of C. decumana and C. Fig. 8.—a. Cross section of a pycnidium of Phoma socia from a grape-fruit leaf. This material was fixed in chromo-acetic acid, embeddedin parafiin, sectioned, and stained in saffranin and gentian outlined with the aid of a camera lucida. 6, Germinationof conidia of Phoma socia after 24 hours in water, c. Mycelium of thisfungus in old cultures. ACIDITY AND RESISTANCE TO CANKER It is generally conceded by both nurserymen and growers and has beensubstantiated by the field observations of the writer that Satsuma orangesare not as susceptible to Citrus canker as grapefruit. This differencemay be noted when both species are grown in locations where they areequally exposed to infection. The tolerance of bacteria to acidity hasbeen found to be relatively low. Resistance to certain fungus diseases,as, for example, the resistance of hard wheat to rust, has been found (3) 1 Phoma socia, sp. nov. Pcrithedis irregulariter distributis, globosisplu
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagricul, bookyear1913
