. Figure 9. Blackfire or angular leafspot in the seedbed. Spots at first are dark and watery. the field. They are irregular in outline (Figure 9), only rarely perfectly round, with no definite margin or halo. These characters make it easy to distinguish them from wildfire spots. At first they give one the impression of flea beetle injuries, but closer examination shows that the leaf tissue is not eaten but is collapsed and sunken, with the epidermis intact. As the spots get older and dry after a few days, the tissue becomes brittle and easily cracks and falls out, leaving irregular, ragged hol
. Figure 9. Blackfire or angular leafspot in the seedbed. Spots at first are dark and watery. the field. They are irregular in outline (Figure 9), only rarely perfectly round, with no definite margin or halo. These characters make it easy to distinguish them from wildfire spots. At first they give one the impression of flea beetle injuries, but closer examination shows that the leaf tissue is not eaten but is collapsed and sunken, with the epidermis intact. As the spots get older and dry after a few days, the tissue becomes brittle and easily cracks and falls out, leaving irregular, ragged holes. As the disease pro- gresses, the leaves become somewhat distorted and the margins and tips turn downward. In severe cases the plants are badly stunted but not killed. When examined under the microscope, the leaf tissue is found to be collapsed and disintegrated in a soft rot and teeming with motile bacteria. In the field, usually only a small percentage of the plants is attacked. The writer has never found more than 10 percent infection, and the disease
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Keywords: ., bookcentury1900, bookpublishernewhavenconnec, booksubjecttobacco
