What is the difference between biological control and pesticides?

Answer 1

Pesticides.

Pests that affect human health and crops are a major problem.

However, one possible consequence of using pesticides is that beneficial

organisms living in the same environment as the pests could also be

harmed. This can happen because many pesticides kill more than just

the pest. For example, the lygus bug are pest that feeds

on alfalfa and canola plants and causes severe damage to these crops.

However, pesticides that are sprayed to kill lygus bugs also kill bees.

Another downside to using pesticides is that they can also harm the

beneficial insects that normally prey on the pests. This can result in

the populations of pests actually increasing because there are fewer

organisms to prey on them!

Biological control.

Another way to control insect pests is to use their natural enemies.

This method, called biological control, can be very effective and limits

or eliminates the need for pesticides. For example, leafy spurge is a

weed that was accidentally introduced into Canada in the late 1800s . Leafy spurge grows faster than naturally occurring

pasture grasses. Cattle will not eat leafy spurge, so land that is infested

with this weed cannot carry livestock. The black dot spurge beetle is a

small beetle that feeds on leafy spurge. The beetle was introduced into Alberta in 1983, and has been very successful in

controlling the spread of leafy spurge. Desirable plants, such as pasture

and rangeland grasses, are returning to the areas where leafy spurge

used to grow. Although biological control can work very well, there can be risks.

Whenever a new organism that is not native to the area is introduced

to an ecosystem, there is always a risk that it will cause harm.