. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 247 Conidia (=Diplodina citrullina) Pycnidia similar to the peri- thecia, spores 2-celled, hyaline, straight or curved, more or less cylindric, 10-18 x 3-5 /*. The fungus was isolated in pure culture by Grossenbacher ^"^ from muskmelons by direct transfer of diseased tissue to potato agar. Inoculations from these cultures proved the fungus capable of entering healthy uninjured tissue, the disease showing about six days after in- oculation. The brownish pycnidia origi- nate from an extensive
. The fungi which cause plant disease . Plant diseases; Fungi. THE FUNGI WHICH CAUSE PLANT DISEASE 247 Conidia (=Diplodina citrullina) Pycnidia similar to the peri- thecia, spores 2-celled, hyaline, straight or curved, more or less cylindric, 10-18 x 3-5 /*. The fungus was isolated in pure culture by Grossenbacher ^"^ from muskmelons by direct transfer of diseased tissue to potato agar. Inoculations from these cultures proved the fungus capable of entering healthy uninjured tissue, the disease showing about six days after in- oculation. The brownish pycnidia origi- nate from an extensive subepidermal, partially cortical, much-branched, brown- ish myceUum but soon break through and appear almost superficial. When mois- ^'°eri\fecTum-anS: a1: tened, spores issue in coils. Darker peri- *®'' Klebahn. thecia, nearly superficial, are found on old diseased spots. Both ascospores and conidia are capable of causing infection. Inocu- lations on pumpkin and watermelon gave positive results; these on cucumber, West Indian gherkin, squash, pumpkin, and gourd were negative. The same fungus has been reported as cause of canker of tomatoes.^ M. tabifica (P. & D.) Johns.^-*'" Perithecia rounded, brown; asci oblong-clavate, 8-spored; spores hyaline, upper cell larger, 21 x /x. Pycnidia (=Phoma) subglobose; conidia elliptic, hyaline, 5-7 x fi, escaping as a gelatinous cirrus. This conidial form, common on beets causing leaf spot through- out the summer, is said by Prillieux and Delacroix to be connected with M. tabifica the perithecial form, which is found upon the dead petioles at the end of the season. Convincing evidence^ of this connection seems wanting. The conidial stage ^"^ is variously known as Phoma betas, Phoma sphserosperma, Phyllosticta tabifica. The Phoma-form from stems and rotten roots and the Phyllosticta-forms from leaves were both studied by Hedgcock ^"' in pure cultures on many media and many inoculations were made, all leading to t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfungi, bookyear1913
