Chemical Pest Control
When faced with a pest or disease, there is a confusing array of chemicals available. So which one should you use?
When faced with a pest, your first response may be to reach for a chemical, but are you using the right one? Garden pesticides fall into three categories: insecticides (for insects and mites), fungicides (for fungi or mushrooms) and molluscicides (slugs and snails). A growing number are made from naturally occurring chemicals, and can be used by organic gardeners, but many are of synthetic origin.
When using pesticides, it is really important to follow the instructions closely. Store in a cool, frost-free location, out of direct sunlight, away from children and pets. Only buy the amount you can use in a year. If you do need to dispose of chemicals, don't put them in the bin or pour them down the sink. Instead, contact your local council's waste removal team, who can tell you where you can take them for safe disposal. |
Old Chemicals
Since 2002, many familiar garden pesticides, including Malathion, tar oils, permethrin, and derris have been withdrawn. If you still have any of these on a shelf, you cannot use them and must dispose of them. The insecticide bifenthin and the fungicide mancozeb (Dithane) were taken off sale in 2010. After this date, you had only one year to use up any left overs before they were banned.
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Insecticide Types
Fatty Acids or soaps are effective against sap-sucking insects (aphids) and mites. They must come in contact with the pest to work, but leave minimal residues and have limited toxicity to humans. (i.e. Armillatox)
Plant oils are naturally occurring substances extracted from plants. They are contact insecticides, which work against a range of bugs including Vine Weevils and are suitable for use by organic gardeners.
Pyrethrins are extracted from the flower heads of two chrysanthemum species. Though naturally occurring, they are potent contact insecticides, but are used by some organic gardeners.
Pyrethroids are synthetic chemicals similar to pyrethrins. They are contact insecticides and include bifenthin, deltamethrin and lambda-cyhalothrin. All contact insecticides can kill beneficial insects. Not suitable for organic gardeners.
Neonicotinoids are systemic insecticides, which are absorbed by plants, then passed on to any insect that feeds on them. They are particularly effective at combating persistent or hard-to-reach pests like mealy bug. Examples include acetamiprid, imidacloprid and thiacloprid. Toxic to all insects including bees.
Plant oils are naturally occurring substances extracted from plants. They are contact insecticides, which work against a range of bugs including Vine Weevils and are suitable for use by organic gardeners.
Pyrethrins are extracted from the flower heads of two chrysanthemum species. Though naturally occurring, they are potent contact insecticides, but are used by some organic gardeners.
Pyrethroids are synthetic chemicals similar to pyrethrins. They are contact insecticides and include bifenthin, deltamethrin and lambda-cyhalothrin. All contact insecticides can kill beneficial insects. Not suitable for organic gardeners.
Neonicotinoids are systemic insecticides, which are absorbed by plants, then passed on to any insect that feeds on them. They are particularly effective at combating persistent or hard-to-reach pests like mealy bug. Examples include acetamiprid, imidacloprid and thiacloprid. Toxic to all insects including bees.