Diagnosis procedure

Making a good diagnosis requires proper preparation. With this in mind we recommend you read the following carefully, and also refer to two important chapters that will help you better to define the location of diseased plants in the field and locate disease symptoms and their characteristics on plants.

The identification of tobacco diseases is not easy and many mistakes can be made in the process. In order to put the odds on your side, we recommend the following procedure:

•  Choose the plants with early, representative symptoms of the disease.

It is essential to pull out the whole plant including roots. Do so with care and wash the roots.

•  Collect all available information on :

- the disease and its symptoms (distribution of diseased plants in the field and location of symptoms on the plant, rate of speed, weather conditions prior to disease occurence or possibly promoting its development ...);

- the plant (variety information, seed quality...) (figure 1 and 2) ;

- the field (environmental conditions, soil characteristics, previous crops, addition of soil or manure...)

- the cultural practices (fertilisation, irrigation methods and their frequency, water quantity, pesticide applications in the field or in the surroundings (figure 3) ;

- the environment of tobacco plant and field (figures 4 et 5).

Figure 1	Figure 2	Figure 3	Figure 4	Figure 5