Organic Gardening

The organic gardener has several options for the biological control of pests. One of the earliest forms of organic pest management was to simply introduce predator species in the garden, the most common being ladybugs and praying mantis. Garden supply companies were quick to make available these natural predators, usually in the form of eggs, but in some cases selling live insects. You can thus introduce them en-mass, or you may choose to use the slower, and more natural method of simply encouraging the local populations of predatory species. Praying Mantis will eat beneficial insects as well as pests, so you may not want to have a large population invade your garden all at once, but encourage the few natural visitors.

Many people think of birds as garden-pests, but here too it really depends on the species. Some birds do not eat plants or fruit, but live on insects. Encouraging such species by providing bird houses near the garden will help prevent insect infestations. As we pointed out for the Praying Mantis, insectivore birds are indiscriminate eaters and will consume beneficial bugs as readily as pests, so it is best to maintain a delicate balance — nature tends to maintain it’s own balancing act, too many insect eaters in your garden will eat themselves out of house and home, and the will move on to better hunting grounds.

Bats are also great bug-eaters, though they rely mostly on night-flying insects. So if your garden is plagued by catepillars that grow into moths, you can reduce their numbers the following season by putting bat-houses in the trees near your garden. The bats will eat the moths, reducing the numbers available to lay the eggs that hatch into plant-eating catepillars.

You can also attack many pests on the micro-scale. Making compost-tea and spraying it on your plants can help prevent destructive bacteria and molds, as well as some insects. A properly made compost-tea (and we will discuss how to make that in a future post) will have beneficial bacteria, nemotodes and fungi, all of which work together to kill or displace the harmful sorts. Added to the soil, the tea will also help make minerals available to your plants, and helps aereate the soil so that plant roots get the oxygen they need.

Experience is the best teacher when it comes to biological control. Your specific needs are dictated by the types of plants your grow, and the types of pests and diseases that affect them. Be observant! If your plants have tiny aphids sucking the life out them, be sure you look close enough to notice them. If there are chunks eaten out of the leaves, try to find the culprit. Look at the undersides of the leaves, and observe the plant at different times of day. Watch the predators at work in your garden and see which species of predator prefers which prey, so you will know which ones you need when a pest species gets too numerous.