. Botany for agricultural students . Botany. 370 THALLOPHYTES velvety appearance. These erect hyphae are conidiophores and bear conidiospores as shown at B in Figure 320. The conidi- osporcs are scattered by the wind and upon germination grow directly into hj^phae which can penetrate a young shoot and start the disease anew. In late summer after the produc- tion of conidiospores is over, the knot becomes black and on its surface occur numerous small papillae which are the flask - shaped perithecia, opening with a pore and lined on the inside with asci as shown at C n Figwe 320. The asco- spore
. Botany for agricultural students . Botany. 370 THALLOPHYTES velvety appearance. These erect hyphae are conidiophores and bear conidiospores as shown at B in Figure 320. The conidi- osporcs are scattered by the wind and upon germination grow directly into hj^phae which can penetrate a young shoot and start the disease anew. In late summer after the produc- tion of conidiospores is over, the knot becomes black and on its surface occur numerous small papillae which are the flask - shaped perithecia, opening with a pore and lined on the inside with asci as shown at C n Figwe 320. The asco- spores are mature and ready to be distributed early the next spring. It follows then that the disease may be spread dur- ing the early spring by ascospores or during late spring and summer by the conidiospores. The de- struction of the knots be- fore the shedding of the spores will check the dis- ease. Bordeaux mixture applied at proper times is useful in checking the dis- eiise, but most attention should be given to the de- struction of the diseased Fig. 320. — Black Knot, Plowrightia morbosa. A, branch of a Plum, showing the wart-like excrescences caused by the Fungus; B, conidiophores producing conidiospores (X 500), and at the right a conidiospore germinating; C, two perithecia sectioned lengthwise, showing the asci and paraphyscs within (X 50); D, asci and paraphyses more highly magnified. Ergot (Claviceps purpurea and Paspali).' — Ergot is a parasite on the young ovaries of the Grasses, being especially common on Rye and occurring sometimes on Wheat, Barley, and a number of > Ergot and Ergotism. Press Bulletin ZS, Nebraska Agr. Exp. Sta., 1906. Life History and Poisonous Properties of Claviceps Paspali. Vol. 7, No. 9, pp. 401-406, Jour. Agr. Research, U. S. Dept. Agr., Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perf
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