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Agar Plate Tests
At present, many of our disease tests are carried out using the agar plate method. Tests on cereals using this method can provide information on more than one seed-borne pathogen. As in previous years, we will report all pathogens considered to be of importance at no extra charge. This service is of particular importance to organic farmers and to conventional farmers when making decisions on seed treatment/management. Advice on interpretation of results is available from both SAC and the OSTS.
Wheat
Both Microdochium nivale (Fusarium) and Stagonosphora nodorum (Septoria) can cause pre-emergence blight. S. nodorum is less common on seed than M.nivale.
When S. nodorum is reported in the seed test, the percentage should be added to the M.nivale percentage and seed treatment/management decisions made on the combined total.
Barley
The Leaf Stripe test now includes a report on levels of Net Blotch and M.nivale.
Seed-borne Net Blotch is important as a source of inoculum, particularly in areas where it has not previously been a problem.
M. nivale is only of importance in spring barley if seed is sown very early, eg, December/January. There is no evidence to suggest that barley sown at normal sowing times is at risk.
Ergot
In the last few years, we have seen an increase in the levels of ergot in cereal seed, particularly barley. Grasses tend to provide the main source of inoculum, although contaminated seed can also contribute. It is therefore advisable not to sow farm-saved seed where ergot levels exceed the certification standard of 3 pieces of ergot per 500g (minimum standard). For further information on ergot control, contact SAC or the OSTS .
Loose Smut and Bunt
The smut test involves the examination of 1000 embryos for the presence of fungal hyphae. The maximum permitted infection in certified seed is 0.5%. It is therefore advisable not to sow farm-saved seed where levels exceed 0.5% without an effective seed treatment.
The bunt test involves a microscopic examination with results reported as the number of Tilletia caries (bunt) spores found per seed. If present, bunt balls will be reported as a percentage.
Advice on interpretation of results is available from both SAC and the OSTS.
Peas and Beans
An Ascochyta advisory germination package provides customers with considerable savings over the cost of individual tests.
Stem Nematode in Field Beans
More than 50% of field bean samples tested for stem nematode were infected last year. Infected seed is an important source of introducing nematodes to non-infected fields. The nematodes can remain viable for many years placing future bean crops at risk of damage. It is likely that the demand for field bean will remain high in 2001/2. It is advisable to await the result of the stem nematode test before proceeding with other seed quality tests. It is therefore important to send samples in well before sowing time.
Organic Growers
Our seed testing packages are of particular value to organic growers. Interpretation of results will differ depending on whether seed is for multiplication or cropping. Please contact the OSTS for further advice.
Quality Assurance
Our seed health testing laboratory is accredited to both the International Seed Testing Association and UKAS to the ISO/1EC 7025 Standard. Our laboratory aims to give customer confidence and satisfaction in the technical integrity of our test results and in the service we provide. For more information contact Valerie Cockerell
Valerie Cockerell
Seed Pathologist |
