An Introduction to Bacterial Diseases of Plants

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...water-soaked areas enlarge slowly or rapidly according to the age of the bolls and the weather conditions. If the bolls are small when attacked they drop off, and if large they become first green-spotted, then brown or black-spotted and sunken in the attacked parts, and the lint either fails to develop under the spots or becomes wet, brown-stained and rotten (Fig. 246). The pods may also become one-sided in their development. On the stems, particularly the upper and softer terminal branches, the elongated water-soaked spots end in long sunken black stripes (Fig. 247) and the branch either shrivels and dies or is broken over. The amount of branch infection varies greatly according to the season and the variety. The main stem of young plants is also subject to attack and may be killed. From the older spots, especially on bolls and stems, there is often a yellowish bacterial ooze which dries in the form of yellowishwhite granules, scales or crusts. This disease is widespread in our Southern States and has been reported also from other parts of the world. I have proved it to occur in Asia (Turkestan) by cultivating my organism out of diseased cotton stems received from Tashkent (Dr. Schroder's cotton gummosis), and with pure cultures of it have reproduced the typical disease in American cotton on both leaves and stems in one of our hothouses (1909). I have also isolated it from stems of Egyptian cotton grown at Zomba in Fig. 241.--Angular leaf-spot of cotton showing varying manner of infection dependent on age. (See next page.) East Africa (Nyassaland), and more recently (1915) from cotton grown in Pretoria in S. Africa. In 1915, Bovell and Dash reported it as serious on late cottons in the Barbados. In 1918 Reinking reported it from the Philippines. Miss Doidg...