Physical Pest Controls Physical controls include floating row cover, a fine cloth netting that prevents insects from laying their eggs on plant leaves, or barriers to deter slugs or ants. Hand picking of insect eggs and larvae or removal of infested leaves are also examples of physical controls. Physical controls are the preferred choice because they involve minimum disruption of the ecosystem. Biological Pest Controls Biological controls are essentially those that nature has provided. Most of the time they work quite well without any human intervention.
All pests have predators which keep their populations in check.
Some important predators for insect pests are birds, other insects, or parasites. When you see birds, lacewings or lady bugs in the garden, you know that they are eating your pests. Now and then, pests get the upper hand. Usually this is temporary, and balance is restored in time. However, sometimes we need to help out a little by supplementing the predator levels.