The aim of the working sheets is to give detailed descriptions of methods for testing seed samples to determine the presence of specific pathogens. It is hoped that they will be useful for plant pathologists working in routine seed testing as well as for those working in research. In principle, the working sheets contain information only on matters relating to specific pathogens and specific hosts. The general aspects of seed health testing are treated in Section 1.2 of the handbook, and the two parts of the handbook supplement each other. In the working sheets a detailed description is given of all available methods which the author(s) consider(s) useful. The methods are evaluated as regards reproducibility and agronomic value of the test results.
Description of a method in these working sheets does not imply formal recognition by ISTA. Although many of the methods described in this handbook have been evaluated in comparative tests they cannot be considered to have been validated. Only those methods described in the Annexe to Chapter 7 of the International Rules for Seed Testing may be included in the scope of accreditation and used on an ISTA certificate.  Methods that have been validated and accepted into the Annexe to Chapter 7 of the International Rules for Seed Testing will be removed from this Handbook.