Measurement of Faba Bean Diseases
3.7. Scale for Rating Bean Yellow Mosaic
(After C.C.Bernier, University of Manitoba, Canada)
|
DESCRIPTION
|
DISEASE
RATING a/
|
|
| Foliar
Symptoms |
||
| None |
0
|
|
| Mild, barely visible |
1
|
|
| Moderate, pronounced mottle |
2
|
|
| Severe mosaic, leaf crinkling and distortion |
3
|
|
| Necrosis | ||
| None |
0
|
|
| Slight necrosis on top leaves and petioles |
1
|
|
| Moderate to severe necrosis of top leaves and petioles |
2
|
|
| Necrosis
on top part of plant as in 2, but necrosis on stem extending down to the mid-point |
3
|
|
| Necrosis severe on middle and lower part of stem |
4
|
|
| Stunting | ||
| None |
0
|
|
| Stunting restricted to top parts of the plant |
1
|
|
| Stunting
occurs early and pronounced |
2
|
