1.      Estimating severity with a percentage scale

1.1.     Download the DISEASE.PRO software (9,12) and copy it in your computer. Run the program by clicking twice on Disease.exe.

1.2.     Assess disease severity on 40 leaves using the percentage scale.

1.2.1.     Wipe all score cards (Menu 9).

1.2.2.     Go to Menu 1 and select 40 leaves with no actual percentage to be shown.

1.2.3.     Go to Menu 2 and select a disease. In the case of early leaf spot, late leaf spot and mixed leaf spots also select lesion size and presence or absence of chlorosis. Write down your selection because you will use the same settings in the next step.

1.2.4.     Go to Menu 3 and estimate the percent of infection for each diseased leaf.

1.2.5.     Go to Menu 7 to write your data to a file. This file will be saved in the directory of DISEASE.PRO.

1.3.     Open the file that you recently created with EXCEL. If you can’t see your file, choose All Files in File of type. In the Text Import Wizard choose Delimited, Next, Space, and Finish. Copy and paste your results into the appropriate columns of Table A in the EXCEL file Estimating disease severity. Tables and figures on this file are defined with capital letters, e.g., Table A, Table B, Figure A, etc.

2.      Estimating severity with a Horsfall-Barratt scale

2.1.     Repeat the exercise above but this time estimate disease severity with the former CIP scale, which is a Horsfall-Barratt scale (Table 1).

2.1.1.     Wipe all score cards (Menu 9).

2.1.2.     Go to Menu 1 and select 40 leaves with no actual percentage to be shown.

2.1.3.     Go to Menu 2 and select the same settings that you used in the previous activity (disease, lesion size, and presence or absence of chlorosis).

2.1.4.     Go to Menu 3 and assign one of the class values from the Horsfall-Barratt scale for each diseased leaf – don’t estimate the percent infection.

2.1.5.     Go to Menu 7 to write your data to a file. This file will be saved in the directory of DISEASE.PRO.

2.2.     Open the file that you recently created with EXCEL. Copy and paste your results into the appropriate columns of Table B in the file Estimating disease severity.