Around a year ago, fears were at their height over the possible loss of vast numbers of pesticides leaving problems such as mildew, rust spot and weeds to run riot. Since then, the immediate threat has receded a little. Some products have been given a stay of execution and some new products have appeared on the market. But there remains real cause for concern.
New EU rules on pesticides came into force in June of last year. In theory, this meant that many products could have been withdrawn with effect from 2012. However, due to the normal mixture of administrative hold-ups and Government compromise, the implementation has been delayed.
Cathy Knott, researcher and acknowledged expert on herbicides, points out that growers of field vegetables can still use many of the threatened products. "The timetable has slipped," she explains. "Linuron (which controls weeds in carrots, root vegetables and onions) was due to be phased out in 2013. Now the date is 2016."
Herbicides on notice
The same applies to pendimethalin, which is generally used to control knot grass and black bindweed. Pendimethalin is currently due to be phased out in 2016. In addition, there is a use-up period - typically of 18 months. "This should give growers and the chemical companies a bit more time to sort things out," says Knott. However, she sounds a cautionary note. "If we can't find a replacement and we lose pendimethalin, it will be a disaster."
Other herbicides are also at risk. Flumioxazin - used on a range of broad-leaved weeds - is due to be reviewed in 2015. Knott suggests that growers of lettuce and celery could be hit very badly if these products were removed from the market.
She points out that the development of new products has been particularly slow. The situation has been aggravated by the European Water Framework Directive. "Europe is a very difficult place to introduce agents," she says. "We have to produce data on the effect on non-target plants and on the water system."
Although there are some radical new herbicide products being introduced by the Japanese, it will be some years before they reach the British market, she adds. However, many existing products have been given extensions of authorisations (EoAs) that license them for a wider range of uses.
Another major issue is glyphosate weedkillers such as Monsanto's Round Up, which is widely used on broadleaf weeds. Registration of these products was due to end this summer and there were fears that they might be categorised as endocrine disruptors and consequently outlawed by the EU. However, according to Knott, the danger seems to have passed and the European Commission seems to have no appetite for outlawing such an important herbicide.
Chemical giant BASF has been given EoAs for a number of its herbicides. Wing-P has been licensed for use on alliums and brassicas. Field vegetable product manager Robert Storer explains: "This only came in at the end of last year, so this is our first whole season with this product." Stomp Aqua can now be used with post-transplant brassicas. However, the pesticide requires plenty of moisture in the ground.
BASF has also won the licence to distribute the US product Serenade (see box). This is a biological fungicide based on the bacterium Bacillus subtilis. It competes with other pathogens, depriving the fungi of the nutrients that they need. It also activates the immune system of the plant and produces metabolites that interfere with the fungus.
Most of the activity in the industry has centred around pesticides rather than herbicides. Allium & Brassica Centre agronomist Simon Jackson explains: "We have lost quite a number of pesticides over the past few years. We don't think that many more will go. The industry seems to be concentrating on finding new applications for existing products."
Syngenta expects label approval for REVUS (mandipropamid) for control of downy mildew in lettuce in time for the 2012 season. "Subject to registration, it is also hoped to introduce several new products in the near future," according to technical manager Jon Ogborn. These include emamectin, an insecticide that is effective against caterpillars and thrips. It will initially be introduced into fruit and later into vegetables.
Syngenta will also introduce isopyrazam, a broad-spectrum fungicide that binds closely to leaf wax, offering excellent persistence. In addition, the firm is planning to launch a novel product based on an extract of giant knotweed.
Already sold in the USA, where it is also approved for use in organic production, the extract activates the plant's natural defences against fungal infection. It is planned to obtain approvals for use in fruit and vegetables.
Pesticide manufacturer Certis does not expect to be introducing any completely new products over the next year. Technical officer Alan Horgan says: "It currently costs around £250,000 to get full approval for a new product, so we tend to be wary about new launches."
However, the firm has made some launches in recent months. Cosine, which attacks mildew and has the active ingredient cyflufenamid, gained full label approval last year. It can be used to prevent an outbreak of powdery mildew or to cure an existing outbreak. It is approved for use on apples and pears and can be used twice in any year, and up to 28 days before picking.
Last year, Certis also introduced the herbicide Finalsan Plus, which contains pelargonic acid and maleic hydrazide. It will attack anything from minute seedlings up to young plants of 10cm and can be used to control chickweed, cleavers, annual meadow grass and knotweed.
Certis is only too aware of the problems brought about by the new regulations. One of the company's fungicides, Aliette, was recently banned. The firm is advising to growers to use any remaining stocks before October 2012, the last date on which it can be used legally.
Bayer has not had any of its licences revoked this time. Product manager Nathan Whitesides says: "We lost some products in the past, but most of the ones we have are not at risk." In fact, Bayer has had a number of new approvals over the past year. Biscaya, a neonicotinoid insecticide, has been given full label approval for Brussels sprout, broccoli, calabrese, cabbage, cauliflower, carrot and parsnip. It is designed to kill insects, particularly aphids at the later stages of plant growth when the plants are more open.
It also has EoAs for use on other root vegetables including swede, turnip, horseradish, red beet and salsify. Bayer recommends that Biscaya should be alternated with another insecticide such as its recent introduction, Movento. This will help destroy the aphids throughout the life of the plant and will also prevent the build-up of resistance. It can be used up until seven days before harvest.
Adding to the range
Bayer also has a number of new fungicides. Around a year ago, it introduced Unicur - a mix of strobilurin fluoxastrobin and triazolinthione prothioconazole, aimed primarily at brassicas, carrots and leeks. Recently it added to its range with Rudis, which also has triazolinthione prothioconazole as its active ingredient.
Bayer recommends that Rudis be alternated with another fungicide, Nativo. Up to three applications of Rudis can be used and spraying can occur until 21 days before harvesting.
Manufacturers themselves are also taking action to head off future legislation. Dow Chemicals and Makhteshim have signed up to a new stewardship scheme to promote the responsible use of pesticides. They are particularly concerned to prevent the needless spread of the insecticide Dursban. The "no drift scheme" promotes efficient application.
Bio-fungicides set for market
At least two firms will be marketing bio-fungicides, which are seen as environmentally friendly and have been used in the USA for organic production.
The American product Serenade, made by Agraquest, is being sold under licence by BASF. It contains live bacteria (Bacillus subtilis), which have up to 30 lipopeptides that punch holes in the membranes of the fungal cells.
Other active ingredients in the product boost the immune response of the plant and also promote plant growth. This means that the plant is better able to deal with the fungal infection. The chemical remains active for 10 days after application.
Syngenta is marketing another American product, Regalia, currently produced in the USA by Marone Bio Innovations. It is made from an extract of Reynoutria sachalinensis (giant knotweed) and will spread throughout the leaf of the target plant. It protects plants against infection and can be used on fruit and leafy greens. In the USA, workers can return to the fields only four hours after spraying and the product can be used right up until the crop is harvested.