Less Toxic Controls
Before considering a spray or a treatment (even if it is a less toxic one), consider the following controls first (these controls are part of Integrated Pest Management approach).
Cultural Controls (Habitat Modification)
- Optimum management using healthy garden practices (more to come...)
- Crop rotation (if vegetables are being grown)
- Sanitation – this doesn’t mean ‘garden clean-up’. Healthy gardens need good ground covers and mulches. One example would be removing diseased leaves (i.e., roses with black spot) from the base of plants. Check new plants (before buying) to make sure they are not diseased or infested with insects.
- Fixing leaks and sealing holes and cracks in homes, stairways, etc removes food, water and shelter sources for some pests.
Physical Controls
Trapping – one example is tangle foot or tangle trap, a sticky band placed around a tree trunk to catch female winter moths and prevent them from laying eggs on trees (these should be applied in mid-October and removed in February – do not use these in summer). They are available at local nurseries. Remember that traps are often misused because they trap beneficial insects - for the average garden they aren’t really necessary. For example, beer traps for slugs often trap ground beetles which are highly beneficial and prey on slugs and slug eggs – it is advisable not to use this slug trap!
Pest-proof Barriers – Floating row covers (also called remay covers) which can be either static or moveable can be effective against leaf miners, carrot rust fly, cabbage root maggot, cabbage looper, imported cabbage worm, and others. Copper slug barriers can be used on slug prone crops such as tender leafy greens, strawberries, dahlias, hosta, and marigolds, among others
Hand Picking – get out in the garden with a container and hand pick the pest. Many North Shore gardeners use this tried and true method to get rid of slugs! You can also do this with leaf miners as well.
Water – use a spray of water to ‘wash’ the pest right off the plant. This is a great control for aphids (and sawflies), as the water stream causes the mouth piece on the aphids to break off and beneficials can just climb back on. This is also great for powdery mildew on roses and rhodos.
Mulching – is a very effective physical control for weeds (link to mulch section)
Mechanical Controls: are machines or equipment used to control pests. These include vacuum cleaners, ultra-violet light traps, cultivators for weeds, and string weeders. Pouring boiling water on weeds in patio and pavement cracks is a good example of a very effective mechanical control.
Biological Controls: include releasing beneficial insects (e.g., ladybugs) or applying microscopic organisms like nematodes to control specific pest populations. See the section on beneficial insects above for more info (hyperlink to above section) – also see our sidebar at right for the do’s and don’ts when it comes to beneficial insect releases.
Less Toxic Controls
Baking soda, horticultural oils, insecticidal soaps, pyrethrum and sulfur products (all available at local nurseries and gardening centres) are much safer alternatives to most chemical pesticides. (Click here for some good reasons not to use chemical pesticides)
Corn gluten (a byproduct of the wet-milling process to make cornstarch) is a natural herbicide which kills the roots of sprouting seeds but does not harm established plants like grass, flowers and shrubs. It also has an added benefit of naturally occurring nitrogen (10%) in a slow release form. (Click here for more information)
Ecoclear is a weed and grass killer herbicide derived from common natural ingredients found in vinegar and lemon juice. EcoClear is non-selective, meaning it will kill not only weeds but other plants as well. (Click here for more information)
When you use any chemical control (even those deemed less toxic as mentioned above), be sure to read and follow the manufacturer's instructions for application and safe storage.