Insect Management (Biological Control) in Organic Farming

It is wondering you to know how to manage Insect Management in Organic Farming. But it is too important to make your farming organic for a long time. If you are not serious to manage it your efforts may worthless or your crops may not organic. So here I am presenting some research on how to manage insect for your Organic Farming.

In organic systems, insect pests are managed preventively rather than curatively. The idea is to alter the system so that pests do not find the plants, are controlled by natural enemies, or their damage is kept to a minimum. Insect management is also dependent upon having a healthy organic system. This includes a proper balance of nutrients in the soil and in the plant. Plants that are vigorous have a much better ability to withstand damage caused by insects and disease. Healthy soil and plants, therefore, are the best defense. This section describes the general principles of insect pest management in organic production.

In organic systems, much of the “control” of insect pests is by natural enemies. These natural enemies can be broken into two major categories: predators and parasitoids. Predators catch and eat their prey much like wolves or other carnivores.

There are several predator species commonly found in gardens. Lady beetles are oval and usually red, orange, or yellow with black spots. Lady beetle eggs, laid in groups of 5-20, are oblong and orangish/yellow. Eggs are almost always laid near some prey, so that when the eggs hatch, larvae will have a food source. Larvae are alligator-shaped and are black with yellow or orange spots.

Lacewings are green or brown and have iridescent eyes of green or gold. Their wings have many veins and, as their name implies, appear lacey. Immatures are alligator-shaped and have long sickle-like mouthparts that they use to impale their prey and suck out juices. Lacewing eggs are laid near prey and on the ends of silk threads.

Another common predator is the syrphid fly (flower fly). The adult syrphid has two wings and therefore is a fly, but resembles a bee with its black and gold stripes. The im­mature is a maggot, which feeds on aphids and other soft-bodied insects. The adult is called a “flower” or “hover fly” and it feeds on nectar and pollen. Other less commonly seen predators are minute pirate bugs, big-eyed bugs, assassin bugs, certain stinkbugs, spiders, and soldier beetles.

Some predators spend most of their time on the ground, and climb plants at night to search for prey. The most common of these are the carabids or ground beetles. These are dark-colored, sometimes shiny iridescent beetles that run rapidly along the ground when disturbed. The adults eat many types of things, which is a benefit because these predators will be present even if there are few pests. The immatures of carabid and staphylinid (another group of predators found in the soil) beetles are predaceous and feed almost exclusively on other insects such as caterpillars. Other predators found in the soil are centipedes, and wolf, garden, and jumping spiders.

The other group of natural enemies is parasitoids (or parasites). These are adult insects that usually do not eat their prey, instead they lay their eggs on or in the host (insect) such as a caterpillar, and when the eggs hatch, immatures use the host as food. Some parasitoids are very specific in selection, while others are more general. Many parasitoids are relatively small wasps that will be seldom seen, but the results can be detected if one knows what to look for. For instance, parasitic wasps often attack aphids and other sucking insects resulting in mummified prey. A parasitized aphid will be about two times its normal size and be brownish-tan. The parasitized aphid will not move. If there is no hole in the parasitized aphid, the wasp is still inside. The im­mature wasp completes its development within the mum­mified aphid, until it emerges, leaving a hole in the para­sitized pest. If mummified aphids are present on a leaf that is infested with aphids, no action should be taken.

Tachinid flies are another group of common parasitoids. These flies look like large houseflies and lay their white, oval eggs on the backs of caterpillars and other pests. The eggs hatch and the fly larvae enter and kill the caterpillar.

Two other types of natural enemies are birds and bats. Birds will eat a variety of pests and some beneficial insects too, as will bats. Attracting birds to your farm is possible, but a large scale (larger than just a vegetable field) is usually necessary. Bats can be encouraged to roost nearby by putting up bat houses or being sure not to disturb a nearby colony.

In the field it should NOT be necessary to purchase these various bio-control agents. All of these natural enemies are quite common. A grower just needs to know how to invite and keep these bio-control agents in their system. If they are not present in your field, it could mean that environmental conditions are not conducive to their presence and purchasing them would not help, as once they were released they would leave the area. Purchase of bio-con­trol agents does however; make good sense in greenhouse situations where the beneficial insects can be contained.

Since many adult predators and parasitoids feed on nectar and pollen, it is essential to have these resources nearby. A variety of plants will be more effective than a single species. An example would be several types of clover (red, crimson, sweet, white, etc.) along with more traditional flowers like marigolds, zinnias, etc. The objective is to have continuous nectar and pollen source throughout the season. The closer these flowering plants are to the vegetables the more often the vegetable plants will be searched by the parasitoids or predators. In addition to natural enemies, flowering plants will attract a wide variety of pollinators such as honeybees, bumble bees, wasps, and butterflies.