Double digit Estimation

The method was improved by using two digits, representing the vertical disease progress and an estimate of severity. The first digit gives the relative height of the disease using the original 0-9 Saari-Prescott scale as a measure. The second digit shows the disease severity as a percentage but in terms of 0-9. Because it is difficult to evaluate diseases on dead leaves, disease notes should be taken when at least four leaves are still alive and green (soft to mid-dough growth stage). Then visually evaluate the average percentage severity on only those leaves of the uppermost four that are infected. In practice, the percent severity is estimated on an overall score. The following format is used for scoring severity: 10% coverage = 1, 20% coverage = 2, 30% coverage = 3, 40% coverage = 4, 50% coverage = 5, 60% coverage = 6, 70% coverage = 7, 80% coverage = 8, 90% coverage = 9. The score of 10 is not used.