Natural pesticides – find many of these in your kitchen cupboards!
July 22, 2010 § Leave a comment
In the home garden and allotment a variety of non-toxic, non-systemic natural pesticides can be made from ingredients/chemicals which can be found in the average home.
Natural pesticides have manifold benefits and are tried and tested methods. There is a very minor application hazard and no concern of harmful residues on edible crops. Largely they will not affect natural predators.
Alliums are toxic to soft bodied insects. A spray can be made from garlic and onions (blend and strain) which will paralyze flying insects and damage their soft bodies. This spray also works as a fungicide.
Fresh or powdered chilli peppers in a spray form are great for killing soft bodied insects. They are most effective when mixed with alliums. As a guide use 1 whole bulb of garlic and 2 fresh or 10 dried chilli peppers blended with a cup or two of water, diluted into a gallon of spray. Pepper mixtures work very well on capsicum plants.
Ground cloves are an insect repellent and can kill flying insects. Whizz some cloves in a blender (unless you have it already powdered, though it may not be as potent) or crush with a pestle and mortar and use several tablespoons per gallon of water.
Neem oil is a sophisticated natural oil-based pesticide which suffocates pests and disrupts their habits (like feeding and reproduction). Adding a drop of oil (neem, soybean or cottonseed ideally, but any vegetable oil will work) along with insecticidal or natural soap (or dishwasher soap if you can’t find natural soap, but it’s not quite as good) to any of the above will create an emulsion which suspends the active compounds in the water, allowing them to ‘stick’ to leaves and pests much more effectively than whensimply diluted in water. It is important to add the soap to the water before adding the oil.
Soft bodied insects are killed instantly by 70% or 90% isopropyl rubbing alcohol. This can be applied with a cotton bud directly to each pest or can be sprayed directly onto theplant. Spraying with isopropyl alcohol is a drastic option and not suitable for seedlings-alternative methods should be considered first.
It is crucial that any spray covers all of the pests and this means spraying every square centimetre of your plants and sometimes the soil around plants. When using homemade sprays a very fine fog is the ultimate delivery and for this reason a hand held pump-action fogger is a useful tool. It saves much time, ensures good coverage and facilitates your reach to the underside of leaves. Aim to spray as early in the day as possible. Oil based sprays will have a greater potential to scorch leaves if applied in bright sunlight.
Physical barriers can be placed around plants to deter pests. Copper discs and copper wire are particularly effective for slugs and snails. Mulch mats are also effective (and cheaper). Netting and fleece will keep out just about everything.
The structure of diatomaceous earth damages and dehydrates the bodies of many insects and many soil pests. Diatomaceous earth is a very fine powder which can be spread on the soil or sprayed on the plant in a solution of insecticidal soap and water. It remains active in the soil for many years.
Other barriers which can be placed around the base of plants include a variety of mulches, crushed eggshell or damp wood ashes. Corn meal isused as topdressing to reduce cutworm populations and is used to make a fungicidal tea.