26 February 1999

Seed-bed vital for successful spring linseed

By Louise Impey

RAPID germination and crop establishment should be the aim for spring-drilled linseed, for existing and new growers of the crop alike.

That means waiting to get the seed-bed right and making use of the crops flexible drilling dates, says Jeremy Taylor of breeder Semundo.

"Linseed has a small seed, which should be shallow drilled into moisture. So cultivations need to produce a firm, fine and even seed-bed, in which the moisture has been retained near the surface.

"But spring cultivations should be minimised. Moisture must be conserved and linseed emergence can be restricted by capping. It is also very sensitive to compaction."

Drilling can take place from early March until April without a yield penalty, so there is no need to hurry to get the crop drilled, Mr Taylor stresses. "Getting the seed-bed right is the single most important factor with spring linseed.

"If it does not go into a warm, moist seed-bed, the crop will struggle. Then it will be vulnerable to pest attack and is more likely to suffer from the effects of weed competition."

Growers concerned about the possibility of a late harvest should consider a desiccant to bring harvest date forward and manage any uneven crops, rather than drill too early, he advises.

Semundo advice is to aim for an established plant population of 500 plants a sq m. "Assuming you get 85% germination and 25% field loss, which is what all our trials indicate, the seed rate should be 700/sq m. Drilling depth should be 2cm (0.8in).

"There is no evidence to suggest that this seed rate should be reduced. A weak, thin plant stand is just not desirable with linseed."

A seed treatment for flax flea beetle is advisable, continues Mr Taylor. "Flea beetle can be a big problem and it is unpredictable. Even with a seed treatment it is still wise to monitor crops after emergence. If the weather is warm and beetles are around a follow-up spray may be required."

Seed-borne diseases are another good reason to use treated seed, he believes. "Alternaria is around this year because of the wet weather through flowering last season. Botrytis is another potential problem, as is fusarium. Linseed needs the best start."

Mr Taylor says that the leading spring varieties have already sold out. "The combination of Agenda 2000 and failed autumn drillings has boosted interest in the crop for this year.

"Growers who still have seed of winter variety Oliver left from the autumn, can plant it in the spring without any problems."

The crop can be grown on a range of soil types, provided pH is between 6 and 7. &#42

LINSEED FACTS

&#8226 Seed-bed more important than sowing date.

&#8226 Firm, fine, even tilth, with moisture near surface.

&#8226 Drill early March to April.

&#8226 Target population 500 plants/sq m.

&#8226 Typical 85% germination and 25% field loss means 700 seeds/sq m.

&#8226 Allow for seed weight.

&#8226 Flax flea beetle and fungicide treatment advised.

&#8226 Area aid £467/ha.

Seed treatment

ADAS entomologist Jon Oakley stresses the importance of an insecticidal seed treatment on spring linseed this season. "This will be the first year that growers are not allowed to use post-em sprays of gamma-HCH," he warns. "So if you are relying on controlling the beetles on emerged crops, then you only have pyrethroids, which give variable results." He predicts that flea beetle damage will begin during the first warm and dry spell, which could be any time from the end of February onwards. "It varies each year, although farms with a previous problem are more likely to have an early attack. The amount of damage done depends on the temperature and the conditions of the seed-bed," he adds. "A well-consolidated seed-bed seems to help."