| 0027049 |
Phytophthora blight |
Phytophthora nicotianae |
|
| 1149208 |
Phytophthora blight |
Phytophthora nicotianae |
1976 |
| 1440054 |
Phytophthora blight |
Phytophthora nicotianae |
Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs. |
| 1402039 |
Phytophthora blight |
Phytophthora nicotianae |
Plants cut longitudinally reveal brown to black discoloration of the pith, which is often separated into discs. Discing may not occur in resistant varieties and only a small portion of the pith may be discolored. |
| 1149209 |
Phytophthora blight |
Phytophthora nicotianae |
1976 |
| 1436044 |
blue mold |
Peronospora tabacina |
on upper leaf surface of seedling |
| 1440052 |
Phytophthora blight |
Phytophthora nicotianae |
Black shank is primarily a disease of the roots and the lower stalk of the tobacco. The symptoms of black shank vary with weather conditions, age of plants, stage of disease development, degree of plant resistance, and virulence of the soil-borne fungal pathogen. Stunting is often the first symptom of black shank, but the disease is seldom recognized until plants wilt. At first, wilted plants will recover in the evening hours, but later become permanently wilted, with leaves turning yellow and hanging down the stalk. During the early stages of disease development, an examination of the plant will show a black discoloration of one or more of the larger roots and the interior of the lower stalk. As the disease progresses, the lower part of the stalk becomes black near the soil line, hence the name black shank. In advanced stages of the disease, the tissues in the center of the lower stalk become blackened, and as the pith dries, it becomes segmented into discs. |
| 1436051 |
Phytophthora blight |
Phytophthora nicotianae |
on outside of stem. |
| 1436052 |
Phytophthora blight |
Phytophthora nicotianae |
on inside of stem. |
| 0027046 |
Phytophthora blight |
Phytophthora nicotianae |
|
| 1149207 |
Phytophthora blight |
Phytophthora nicotianae |
1976 |
| 0027050 |
Phytophthora blight |
Phytophthora nicotianae |
|
| 1402038 |
Phytophthora blight |
Phytophthora nicotianae |
Stalks generally develop black lesions which may extend several inches above the ground |
| 1497010 |
Phytophthora blight |
Phytophthora nicotianae |
Black shank on tobacco |
| 1497059 |
Phytophthora blight |
Phytophthora nicotianae |
Black shank on tobacco |
