Industry united in battle to reduce pesticides in water

The water industry and the farming community will come together for the first time at Cereals 2014 to raise awareness of water issues and crop protection.

Severn Trent Water’s catchment manager Jodie Whitehead is keen to stress the importance of collaboration between the two industries.

“Our key message is that we want to work with farmers to solve problems, rather to than to see products being banned. It’s all about working in partnership, raising awareness and looking at the type of schemes that water companies are putting forward to deliver best practice and innovative ways of working together.”

Most pesticides can be removed from raw water, with the exception of metaldehyde. But when a number appear at the same time it causes a challenge to the treatment works.

“If we can reduce the peaks by 50% then the treatments we have in place are absolutely fine.”

But it is metaldehyde in particular that continues to be the bane of water companies. Breaches of the strict EU limit of 0.1µg/litre for any pesticide in water, especially in 2012, have forced EU regulators to put pressure on water companies to solve the metaldehyde problem before 2020.

“If it is not solved, then they will be pushing DEFRA to ban metaldehyde. At this time, there is not a cost effective means of removing it from raw water.”

And although all water companies are working together on new treatment options for all pesticides, the solution is to work in catchment to reduce the risk, says Dr Whitehead.

Strategy

There are a number of strategies that Severn Trent Water are looking at to reduce the incidence of pesticides in water in addition to cultural control methods and ensuring best practice is employed.

For example, information on planned pesticide applications is being provided to the water company via a fortnightly online survey that’s filled in by growers and agronomists in order to provide an early alert within in the Avon and Leam catchment, enabling intake to the waterworks to be managed more effectively.

“If there is a rainfall event and drains are flowing, then with the knowledge of the downstream travel time and pesticide treatments, we can act swiftly to shut down pumps so we don’t abstract during high peaks of pesticide.”

Collaboration helps raise low-drift awareness

    The successful collaboration between industry and growers has helped regulators to take low-drift nozzles into account when approving or re-registering active ingredients in the UK.

    The Say NO to DRIFT stewardship campaign has been established to help secure the future availability of chlorpyrifos. It is providing much impetus to the overall re-registration of chlorpyrifos through the implementation of application guidelines including the use of low-drift nozzles and extended buffer zones.

    And the credit due is to farmers and spray operators, whose willingness to switch to low-drift nozzles and adhere to increased buffer zones for the application of the insecticide gave the Chemicals Regulation Directorate the confidence to make the adjustments to the legislation, says Dow’s James Knight.

    “Without the change in approach by regulators we wouldn’t have got any further, but there is still work to be done.”

    At the moment the change only applies to boom sprayers and arable crops, so a further change is needed for applications to fruit. Although the campaign is still voluntary, growers and sprayer operators are still being reminded of the importance of adhering to the stewardship measures so that when labels change there won’t be a problem. “It is now in the hands of the regulatory authority.”

    Overall the recognition of low-drift nozzles in decision making is very positive for UK agriculture, not only because it has helped to fight the case for maintaining chlorpyrifos, for which there is no direct replacement, and is crucial for the control of key pests such as wheat bulb fly and orange wheat blossom midge. This change will also support the introduction of new chemistry which is currently used by farmers across Europe but not in the UK due to high conservatism in assessment, says Mr Knight.

    This means the use of low-drift nozzles, which have no adverse effect on efficacy of chlorpyrifos, could be taken into account for most insecticides and some herbicides and fungicides in the future.

In a similar manner, an early warning detection system is being developed in the form of an online sampling system located upstream of abstraction points. So if metaldehyde levels start to creep up it indicates that the pump needs to be shut off.

Working with the Metaldehyde Stewardship Group (MSG), which encourages best practice with metaldehyde and has been raising awareness of the water-related issues, a new and industry-wide initiative has been devised to home in on the highest risk water catchment areas.

The two-year pilot scheme follows research into the routes by which metaldehyde reaches water, and the observation in one high-risk catchment which saw a 50% reduction in exceedances during the high pressure season of 2012, compared with the situation in the previous high pressure slug season in 2008. This was achieved through targeted slug pellet product substitution.

The pilots used data from catchment scan modelling and the knowledge that drain flow, slope, proximity to watercourse and soil type were of primary importance. Risk scores were then generated per field within the pilot areas. All areas scoring above a defined threshold score were then designated as high risk fields and as “zero metaldehyde zones”.

The four pilot catchments taking place during 2014 are the Avon and Leam in Warwickshire (Severn Trent Water), Mimmshall in Hertfordshire (Affinity), Pincey Brook in Essex (Thames Water) and Pitsford in Northamptonshire (Anglian Water).

Alongside this pilot scheme is another project involving DEFRA, water companies, MSG and the Environment Agency, looking at how to how to align mapping techniques and scale up to map the whole of England, Wales and Scotland, says Dr Whitehead.

For growers within the pilot areas the scheme is voluntary, explains MSG spokesman, Simon McMunn, yet the early response has been really positive and growers understand that they need to play their part in maintaining the active ingredient.

“We are asking farmers and agronomists to be vigilant with metaldehyde stewardship guidelines across the whole of the catchment, and to abide with MSG guidelines. But on fields that the mapping has designated as ‘high risk’, we are appealing to farmers not to use metaldehyde at all, throughout the 2014 calendar year.

“We are hoping, for the purposes of the pilot, to have a normal or high pressure year, not low pressure, so we don’t get any false results. And we are hoping to see a reduction in exceedances in raw water.”

The delivery mechanism is via Catchment Sensitive Farming officers, who have been meeting with growers in each of the pilot areas. There have been some concerns, the main one being the lack of knowledge about alternative products.

Alternatives

Only two active ingredients will be available to growers in high risk areas, methiocarb and ferric phosphate. But with the approval of methiocarb having been revoked and only available on the market until September 2014, with just one year use-up period, many of the growers in the hot spot areas will to be looking to ferric phosphate, a relative newcomer to the molluscicide market.

Sluxx, manufactured by Certis, has all the features of a top-quality wet extruded pellet with rainfastness and efficacy comparable with top-quality metaldehyde pellets, and a cost per hectare midway between methiocarb and metaldehyde, says the firm’s Robert Lidstone.

But whereas the product is comparable in many aspects, its mode of action is different from metaldehyde and will require growers to adapt their thinking and approach to slug control.

“Ferric phosphate is a stomach poison and when ingested stops the slugs feeding almost immediately. They are not killed outright, but disappear under the surface and die a few days later. Unlike metaldehyde, growers will not see a classic slime trail and dead carcasses, so it’s important to observe the crop.”

Mr Lidstone is encouraging growers to try out the product, understand how it works and gain confidence.

“Some growers will use the product simply because they don’t want to be responsible for contaminating raw water.”

Others are likely to look at the total permissible limit of metaldehyde in a calendar year (700g ai) and may choose to use ferric phosphate on one or more crops, and potatoes would be a good example of this.

But if we have a season like 2012, growers in high-risk situations, for example those with under drained fields where drains may be flowing or about to flow, will need to carefully consider when it is appropriate to use metaldehyde and when they should be using ferric phosphate instead. In other words, a programmed approach to molluscicide treatments.

“If we do this right we will help ease the pressure on metaldehyde.”