Good news for pests could also help the local wildlife to thrive.
More than 80 products used by amateur gardeners to control pests, diseases and lawn weeds have been taken off garden centre shelves after the latest round of checks on active ingredients.
Gardeners who have them in their sheds are required by law to finish using them by December 31. The waste-disposal departments of local councils should have information about safe disposal.
The banned products include such well-known brands such as Vitax House Plant Pest Killer, Murphy Mortegg tar oil wash, the fungicide Spotless, Cutlass, the labour-saving hedge-growth retardant and many types of selective weedkiller for lawns.
Some lawn weedkillers will remain on sale because the active ingredient they contained, dichloroprop, has been reformulated as dichloroprop-p. Other products, such as Jeyes Fluid and Armillatox, both based on tar acids, will remain on the market but will no longer be able to claim control of moss, lichen or liverwort. Again, gardeners cannot legally use them for that purpose after December 31.
Two reviews have led to this clear-out.
First, the Government called for a reappraisal of some insecticides because of concerns over their effects on human health. Companies marketing such products were required to produce additional data to show that they were safe to use.
Many decided that the income derived from particular sales could not support the cost of additional research. This means that several pesticides are being withdrawn for commercial, not safety, reasons - those containing chlorpyrifos (to control soil pests such as cabbage root-fly), dimethoate (sap-sucking insects like aphids), malathion (various insects and mites), permethrin (various insects) and pirimiphos-methyl (Fumite greenhouse smoke cone).
Secondly, the European Union reviewed pesticides approved for use before 1991. Again, additional testing was called for if they were to be included on the EU list. This process is bringing the safety and environmental information about these products up to the level of more recently introduced pesticides. Again, some pesticides have not been put forward as the additional research was too costly for companies - from pounds 400,000 to pounds 800,000 per chemical in some cases.
Some of the withdrawn chemicals have been replaced with new products that comply with the current safety testing requirements.
For instance, the combined fungicide and pesticide Roseclear 2 has been superseded by Roseclear 3. In other instances, organic substances are fairly effective.
These are not subject to EU review as their active ingredients come from natural substances such as pyrethrum, rotenone/derris, vegetable oils, fatty acids and sulphur. Biological methods, which are outside the review, are also available, mainly in glasshouses.
These use other insects to prey on the pests and can be effective, though they are fairly expensive and timing is crucial.
The fact remains that the range of insecticides, fungicides, herbicides and other preparations available to home gardeners is now more restricted than 10 years ago.
The new situation will demand more work from enthusiasts who wish to maintain an immaculate garden but it may encourage them to turn to more natural garden controls, an important consideration as gardens are becoming more significant as habitats for a wide range of wild creatures.
Purely on practicalities, more gardeners will have to adopt organic gardening principles, especially when dealing with some fruit and vegetable problems. Choice of the most appropriate varieties and good cultivation - sensible planting times, adequate spacing, watering and feeding - will produce more robust plants which will be better able to withstand pest and disease attack. The use of crop covers, such as horticultural fleece, can be effective in keeping pests out.
For some fruits and vegetables there are now no pesticides that can be used, other than the organic types. The insecticide bifenthrin can be used on cabbage and other brassicas against flea beetles, caterpillars, aphids and cabbage whitefly. However, only one application is permitted during the growing season, so a difficult decision has to be made on which pest to target.
Bifenthrin can also be used on apples and pears but not on plums. With the loss of synthetic insecticides for use on plums and the removal of tar oil for winter aphid-egg control, aphids and plum moth could become much worse problems on plums.
New pesticides might be developed to replace some of those lost. However, in the immediate future, the reduced range of pesticides means greater reliance on those few that remain. This could lead to problems with pests and diseases gaining resistance to chemicals.
In the worst-case scenario, the inability to control the more damaging pests and diseases may lead to some plants declining in popularity as they become harder to grow well.
On the bright side, gardens could become more wildlife-friendly and cultivation skills could improve.
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|Publication:||The Journal (Newcastle, England)|
|Date:||Aug 16, 2003|
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