24 July 1998

EASY DECISION ON TREATMENT

Many claims are made

about the strength of one

seed treatment over

another. But is there really

that much to choose

between them? We provide

some timely advice.

UNLESS you have specific pest problems choosing a seed treatment this autumn should be simple.

If yellow rust is a worry use a broad-spectrum product, if not use a single purpose treatment. But in all cases treatment is likely to be worthwhile this season.

Cereal growers considering seed treatment choice for this autumn should match the best seed protection material to the variety and the situation in which it is being grown, says Andrew Davy of Proleaf Seeds.

"There are now six major wheat varieties with a yellow rust rating of 5 or less," he points out. "As these are likely to account for 50% of wheat sales this year, it would be wise to treat them with a broad-spectrum product such as Baytan. It gives a much wider window for spring spraying."

He includes Savannah, Reaper, Hussar, Madrigal, Harrier and Equinox in this category and predicts an increase in the use of Baytan. "There is a lot of yellow rust inoculum around and growers will be mindful of their experiences over the past couple of years."

Of the single-purpose seed treatments, Mr Davy believes there is not enough to differentiate between the products technically. "They all do a very good job at controlling the main seed-borne diseases. Growers do not need to agonise over their decision, just buy on availability. With the exception of BYDV control, there is nothing new on the list this year."

He warns against the use of untreated seed. "You only have to see what fusarium can do to realise that seed treatments are an insurance you cant afford to ignore. Plant losses in the region of 50-60% are commonplace with fusarium-infected seed."

Rainfall during ear emergence and flowering will have helped to infect developing seed with fusarium, he adds.

"It is not the right year to experiment without a seed treatment," he cautions. "Growers who want to reduce input costs should reduce seed rates instead. Earlier drilling at lower seed rates will save £10-£20/ha."

Bob Miles at Elsoms Seeds agrees that seed treatment choice is easy. "Differences between the products are only seen at very high levels of disease, so growers need not worry about requesting a particular treatment.

"Prices have been held at last years levels, so there is only £2/t between the single-purpose treatments, which range from £42-£44/t."

He advises growers in high BYDV risk areas to consider the use of Raxil Secur. "It is a big step forward in BYDV control. The chemical is present from day one and growers do not have to worry about the timing of autumn aphicides."

Mr Miles believes the use of untreated seed is both dangerous and unfriendly, particularly where bunt is concerned. "And do not forget that a seed treatment is the only way to control loose smut and leaf stripe in barley. It really is cheap insurance."

James Wallace of Daltons Seeds predicts that the next 12 months will be more exciting for seed treatment developments. "The real advances will come in the next couple of years with new molecules which offer better control of foliar diseases and improved crop safety."

He expects that most farmers will opt for one of the single-purpose dressings, with only those in the high risk areas incurring extra expense by adding wheat bulb fly or BYDV control with an insecticidal treatment.

"Both Evict, containing tefluthrin, and Raxil Secur, imidacloprid, are only cost-effective where growers have a specific problem with the relevant pests," he says. "They add a further £60-£70/t to the cost of the basic seed treatment, so growers are looking at £60-£120/t for seed treated with these products."

He also believes Baytan at £87/t has a useful role in early-drilled crops and those varieties which are prone to yellow rust.

"A wireworm treatment at £20/t is often a sensible precaution in cereals following grass," he adds. "And a manganese product should be used in areas where a deficiency exists." &#42

SEED TREATMENTCHOICES

&#8226 Baytan if yellow rust worries.

&#8226 Raxil Secur if high BYDV risk.

&#8226 Evict if wheat bulb fly threat.

&#8226 Manganese dressing where severe deficiency likely.

&#8226 Little to choose between single purpose treatments.

&#8226 Avoid untreated seed.

&#8226 Big seed treatment developments in the pipeline.