Biological Pest Control

Tomato Hornworm with Wasp EggsWasps can be a nuisance, especially in late summer when the sweet-toothed workers no longer need to engage in nest building activities, and turn their attention to stealing soft drinks, cakes and other sugary treats. A wasp nest close to your home, business premises or children’s playground may need to be removed as some people are uncomfortable around wasps and children in particular can find them upsetting.

However wasps can be beneficial to the environment. They provide food for animals including birds, bears, bats, weasels, rats, mice and badgers. Wasps can also be used to great effect as biological pest control. The BBC recently highlighted a pilot project in Brazilian sugar cane crops. Eggs of the parasitic wasp were released into the fields. When the eggs hatch the tiny wasps  inject their own eggs into those of the sugarcane borer, killing them in the process.

How Biological Pest Control Works

  • A parasitic wasp infected insect pupae are released into an area where pest insects are breeding.
  • At temperatures above fifteen degrees Celsius, one wasp will emerge from each infected pupa. The female wasp then hunts out insect pupae and injects an egg into each one.
  • After hatching inside the pupa, the developing parasitic wasp larva kills and consumes the insect pupa as it grows, preventing the adult pest from emerging and breaking the lifecycle.
  • Mated females are then ready to start the activity again, killing yet more pest insects in the process.

The benefits of biological pest control is that it is a chemical free process. Once the nuisance insect population is eliminated the parasitic wasp population naturally declines as they have no hosts left to prey. However, previous experiments with biological pest control have been disastrous. One of the highest profile cases are the deployment in 1935 of the cane toad from Hawaii to Australia to control the native cane beetle. When the cane beetle had been devoured, the cane toad then turned its attention to eating anything and everything in its path including carrion, beetles, honey, ants, native frogs, small snakes and small mammals.

Nature is a delicate balance and as with using pesticides a professional should always be engaged. If it doubt please call the experts.

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