Chapter 24

Greenhouse Pesticides

Insecticides

Insecticides are biological or chemical compounds designed to kill, injure, reduce the fertility of, or modify the behavior of insect pests. Control may result from killing the insect or otherwise preventing it from engaging in behaviors deemed destructive. Insecticides can be classified a number of different ways, which involve the following categories: 1) method of application, 2) mode of action, and 3) breadth of activity.

Methods of Application

Contact Insecticides

Contact insecticides are sprayed on the insect’s body and poison is absorbed through the body wall. Most soft-bodied insects are vulnerable to contact insecticides.

Systemic Insecticides

Systemic insecticides are delivered through a drip irrigation system or sprayed directly on the vines which, is then absorbed by the plants. Insects feeding on treated vines then receive a dose of the insecticide, causing repellency or death.

Mode of Action

Insecticides can be grouped according to their mode of action (MoA) or the way they destroy or control the target pest. For example, one insecticide may affect insect’s nerves while another may affect moulting.

Breadth of Activity

Broad Spectrum

Broad spectrum insecticides kill a wide variety of insects, usually by affecting a system common to all, such as the nervous system. Broad spectrum pesticides are general purpose killers used when several kinds of insects are a problem.

Target-Specific

Target-specific insecticides are much more selective against insects with certain feeding habits, at certain life stages, or within certain taxonomic groups. For example, chitin inhibitors affect insects only at certain stages in the development of their exoskeleton.

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