Farmers must take extra care when using treated seed to ensure a valuable method of controlling key pests and diseases is not lost. Lee Bennett, national sales manager, Openfield, explains

Seed treatments have increasingly come under the regulatory spotlight over the past couple of years. Rising concern over neonicotinoid compounds and bee safety, fuelled by campaign groups and the media, might have been the trigger, but there is also concern in general over risk to the environment through accidents.

All treatments are potentially under scrutiny, and we all have to play our part to safeguard their use. Despite these concerns it must be remembered that all approved products have been through a rigorous registration process that allows safe use when applied and drilled as directed.

Why should we worry?

Seed treatments are something that farmers take pretty much for granted. Modern dressings began with mercury treatments in the 1920s, which were widely adopted over 50 years ago. These have since been replaced with an armoury of contact and systemic materials, constantly being updated, that control a range of diseases and insect pests.

Treating seed is an effective way of applying fungicides and insecticides. The technique is the only way highly damaging seed-borne diseases like bunt, loose smut and leaf stripe can be controlled. Seed dressings can also provide early protection against a range of damaging foliar diseases.

They also offer a precisely targeted mechanism for dealing with pests. For example, a seed dressing to control grain and bird-cherry aphids can replace a broad spectrum pyrethroid insecticide applied through a crop sprayer, and can deter slugs to the point where pelleting may be reduced.

Similarly, modern neonicotinoid seed treatments offer probably the only reliable and effective control of Myzus persicae in sugar beet and the all-important virus yellows it carries, as well as soil pests. Just over 60g of ai/ha can replace a couple of foliar sprays and a soil-applied granular insecticide.

These materials also offer a step forward in flea beetle control in oilseed rape, again at very low doses, and they reduce early aphids and virus infection.

Used correctly, seed treatments are a cost-effective and safe way of applying pesticides. But we have to remember they are pesticides, and that legislators treat them as such. Registering new products is just as costly and difficult as other agrochemicals, and the need to preserve existing products is equally relevant.

Seed stewardship

The Chemicals Regulation Directorate has asked agrochemical companies to flag up stewardship more as part of the approvals package. Companies have responded by setting up their own seed stewardship schemes. Information is available on company websites; some advisory groups and seed companies are adopting this information and relaying it to farmers.

A cross-industry scheme, the European Seed Treatment Assurance Scheme, is also being developed and should soon be in place.

All seed treatments come under these stewardship guidelines. Although the spotlight has focused on neonicotinoids, which include actives like imidacloprid, clothianidin and thiamethoxam, it is important to note that stewardship guidelines apply to all seed dressings, not just these materials.

Most of the messages are not new - they have been on seed bag labels for years. What is new is growers need to be seen to be acting on these messages.

Key risk areas

The main concerns driving seed stewardship are environmental, and the key factors and how to address them are what we will concentrate on in this academy.

However, it goes without saying that human health is paramount, so drill and seed treatment plant operators should always wear the appropriate protective clothing as outlined on the label, and wash hands after working with treated seed.

Accidental seed spills

Spills potentially carry the biggest risk to the environment, as there is such a concentration of material in one spot. This can attract wildlife, and if wet the seed treatment can dissolve in the water and spread.

To avoid spills, take care when loading the drill. And don't fill the drill where seed spillage is difficult to clear up, such as verges. Handle bags with care and ensure no seed is released in transit, either from the drill or from an empty trailer - be sure to sweep it off first to remove any spilt seed.

Always clear up spilt seed immediately. Small spills can be buried in the field, larger spills should be cleared up into a seed bag for later safe disposal. A spill kit consisting of spade, spare seed bag and label, plus canvas sheet for use when calibrating, should be carried.

Prevent dust

It was dust arising from poorly-treated maize seed at drilling that gave modern seed treatments their initial bad press. In 2008, many bees were killed in Germany as dust containing neonicotinoid settled on flowering crops.

To keep dust to a minimum, make sure a quality dressing is applied to European Seed Association standards. Handle bags with care, and don't drop seed into the hopper from too great a height.

Drills (especially precision vacuum drills) must vent into the soil or onto the ground - not into the air. Some manufacturers offer retro-fitted kits for older vacuum drills that need adapting. Take extra care if it is windy as fine dust can be prone to drift.

Finally, do not tip remaining dust into the drill - leave it in the bag.

Ensure seed is buried

All treated seed must be suitably covered by soil so it does not attract birds and mammals. The most important message here is that broadcasting treated seed is forbidden - and that includes Autocasting oilseed rape. This is not new advice; when imidacloprid was first introduced 10 years ago as an OSR dressing, it was on the label.

It seems quite a few people were not aware of this restriction. Now there is no excuse. And, while the focus may be on neonicotinoids, most seed treatment tags will have a similar phrase.

It is also worth remembering that some seed treatments such as tefluthrin, which controls wheat bulb fly, must be buried adequately to work effectively.

A properly maintained drill operated at the right speed in a good seed-bed will help ensure seed is covered. Do not force the drill round sharp corners or coulters may ride out, and ensure coulters are in the soil and the drill is moving forward before seed is released.

Cloddy seed-beds can be a problem; patience may be needed to achieve a finer tilth. If a lot of seed remains on the surface, a post-drilling harrowing or rolling might be needed as soon as the seed-bed is fit to travel, though it could be argued that seed wasn't buried at the time of drilling.

After drilling

Once drilling is completed, check difficult areas like corners and headlands where seed may be left on surface, and take action to cover it.

Do not re-use seed bags, except to store treated seed, and dispose of them as contaminated waste.

Finally, make and keep a record of the drilling operation.