Off The Shelf Pest Control - The range of low toxic, off the shelf pest control preparations available to gardeners is expanding. Here are some of the main products/ingredients available.

BT - Also sold as Dipel, this naturally occurring bacteria (Bacillus thuringiensis) controls some types of caterpillars. It has been cultured and is available in a powdered form that is mixed and sprayed on to plants.

CONDIES CRYSTALS - (Potassium permanganate) A few drops in a bucket will turn the water pink. Controls powdery mildew and is used by some gardeners to kill ants in potted plants. It is toxic to worms!

COPPER SPRAYS - Copper oxychloride, cupric hydroxide and Bordeaux mixture are used to control a range of fungus diseases including mildews, anthracnose and leaf spots.

DERRIS DUST - Derris is made from the ground root of the rotenone plant (Derris elliptica). It is used to control chewing insects. While it is allowable under organic growing regimes it is toxic to worms, but some gardeners do use it for lawn grub control.

DIATOMACEOUS EARTH - Composed of the ground tiny salt-water organisms called diatoms, insecticide grade diatomaceous earth has microscopically sharp edges that desiccate insects on contact or kill them when ingested. The fine grey powder is mixed with water then sprayed on to plants. Please note that the diatomaceous earth used in swimming pool filters is heat treated and cannot be recommended for use in the garden.

HORTICULTURAL GLUE AND BARRIER PAINTS - These products are applied to the trunks of trees to prevent insects making their way up into the foliage canopy. They are particularly effective against ants, preventing them transporting scale, aphids and other insects from overcrowded colonies located nearby to clean plants.  They can act as effective barriers to a range of caterpillars.

NEEM OIL - This oil is extracted from the neem tree (Azadiracta indica). It kills insects by contact, ingestion and also acts as an anti-feedant. It is commonly sold as a plant spray or mixed with soap based products.

Neem oil has a long history of use in countries like India where it can be found in everything from soap and toothpaste to pest control products.

Under Australian law neem is not registered as a pest control product for plants. At this stage, it is only registered for control of fleas on cats and dogs. This makes it illegal for anyone to recommend neem oil for control of garden pests. Doing so risks prosecution.

Adding to the confusion for gardeners is the fact that several neem based products can be found on the shelves of nursery and garden outlets. Examination of label details and recommendations reveals that manufacturers are very careful not to make any insecticidal claims about neem.

Some neem products are mixed with soap. Claims made in relation to insect control on these products relates to the soap they contain. In other instances label details promote neem plant sprays as fertiliser enhancers, soil conditioners and root drenches.

OIL BASED SPRAYS - Oil sprays derived from petroleum such as white oil and PestOil are frowned upon under organic certification. Fortunately, it is possible to make up your own vegetable based oil spray (see Do It Yourself Control). Oil sprays are great for controlling a wide range of insect pests including scale, mites, aphids and citrus leaf miner. Commercial products such as EcoOil contain plant based oil and are a better choice.

POTASSIUM BICARBONATE - Exciting news for gardeners on the disease control front with the official registration of Australia’s first organic fungicide.  EcoRose (based on potassium bicarbonate) has recently been released as the home garden version of EcoCarb. It is exactly the same product, but comes in a smaller size for home garden use. A broad spectrum fungicide that controls powdery mildew and black spot, the new registration applies for use of the product on grapes and roses, although it receives regulatory approval in the USA for a wide range of foliar diseases.

PHEROMONE TRAPS - A pheromone is a non-toxic species-specific scent produced by the female insect to attract the male. Pheromones are often used as the attractant in baits and traps. Products available include Wild May and Eco-Naturalure for fruit fly control.

PYRETHRUM - Natural pyrethrum is extracted from the flowers of Chrysanthemum cinerariafolium. It will kill predators if used indiscriminately, so be sure to spray late in the day when bees have returned to their hives. It is used for a wide range of insect pests, particularly beetles. Synthetic pyrethroids or products in which natural pyrethrum is mixed with piperonyl butoxide are not allowable under organic certification.

SEAWEED SPRAYS - Foliar sprays made from seaweed have been found to be very effective in reducing fungus diseases that affect leaves and flowers. Seaweed extract also increases the microbial activity in the soil. This activity helps to make existing nutrients more available to plants. Seaweed also increases the ability of plants to cope with extremes of temperature including frost and drought.

SOAP SPRAYS - Soap sprays break down the waxy layer of the insect exoskeleton causing the insect to dehydrate. Be sure to use pure soap and not detergent. Commercial products include Natrasoap.

SULPHUR - Dusting sulphur and wettable sulphur preparations are effective against mites and powdery mildew.

Products acceptable under organic growing regimes are constantly under review, so always check with your local organic growing group or certifying agency [http://www.daff.gov.au/aqis/export/organic-bio-dynamic] before using any pest control product.

(This text contains an edited extract from my book, 'Organic Vegetable Gardening', published by ABC Books, plus additional information). See [What's New]