There are numerous articles on plant diseases published in which the authors note that the pest in question was found on seed. Often the relevance of such publications is questionable. The presence of a plant pathogen on seed does not necessarily mean that it transmits a disease or that seed is a pathway for establishment of the pathogen. The conclusion drawn of a pest being seed borne or seed transmitted may be based on experimental evidence, limited observations, or in some cases, simply suggestive statements.

In some instances, even when seed provide the means for a pest to enter, establish or spread, there is no technical justification for regulating them. The seed industry has begun preparing Technical Fact Sheets for these cases (see below).

Many pests that are not seed transmitted or for which seed is not a pathway for establishment are, nevertheless, regulated. Seed companies have to meet these requirements, even when they are not technically justified, in order to move seed. To facilitate trade, ISHI-Veg on occasion develops detection methods for seed that has not been proven to be a pathway for the entry and spread of disease. The protocols for such tests are listed below.

Test Protocols:

• Detection method for Candidatus Liberibacter solanacearum in Carrot seed
• Detection method for  Pospiviroids in Tomato seed

Technical Fact Sheets:

• Fact Sheet – Southern tomato virus