. Figure 23. Ringspot. Continuous lines follow the veins or form rings between them. Since no tobacco plants remain alive over winter in this climate, and all the virus must die out every winter, it is difficult to explain how the disease gets into the fields each year.

---

Size: 1841px × 2714px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: ., bookcentury1900, bookpublishernewhavenconnec, booksubjecttobacco