activity, deters slugs from hollowing out the grain, and also deters birds. Bayer expects
In addition to fungicides and insecticides, seed may also be treated with nematocides
to control nematodes, or with bird and animal repellants, or with growth stimulants
(such as Ergostim for maize) or with chemicals to protect the seed from herbicides.
Further details: see the UK Pesticide Guide (The “Green Book”) published by the
British Crop Protection Council/CABI, and the PNW Weed Management Handbook
(available online).
Advantages of Seed Dressing:
- logistics: the plants are protected at the appropriate time, when they are young and
weak; - environment: pesticides etc are applied to the seed only, not blanket sprayed on the
soil or into the air; - economics: less seed per unit area is needed, and the extra yield/quality often more
than pays for the cost of the dressing.
The chemicals normally used include:
- active Agent—the fungicide or insecticide;
- glutinous Agent—to make sure the chemical sticks to the entire seed surface;
- diluting Agent—to improve the distribution of the chemical so that the seed is
covered uniformly; - warning Colour—a coloured dye.
Sometimes the seed is coated before treatment with a glutinous agent such as textrine
linseed oil. This protects the seed to some extent from attack by wireworms and birds.
Seed Dressing for Disease Prevention
Seed treatment is mainly used to reduce the incidence of diseases which are found on
the surface of seed, for example Bunt (Tiletia cares) of wheat. Some other diseases can
also be controlled to some extent, such as:
- diseases inside the seed, eg Loose Smut (Ustilago nuda) of wheat and barley;
- diseases which attack the seed from the soil, eg the seedling Blights;
- diseases transmitted by wind, eg Powdery Mildew (Erysiphe graminis).
Fungicides
There are both systemic and non-systemic forms of fungicidal seed dressings, used
according to the fungal disease to be controlled.
The older type of organomercurial seed dressings are slowly being replaced, and
fortunately are now banned in many countries due to their toxicity to birds, mammals
and so on. Among the evils of this type of poison is their long persistence in a
potentially lethal form.
58 TONY WINCH
to replace Secur with the new “Deter” range, based on a new insecticide clothianidin.
A further range of seed dressings, “Redigo”, “Redigo Twin” and “Raxil Pro” was
launched by Bayer in 2005.
Composition of Seed Dressing: