Biological control for indoor plants

Steve and Val Bradley explain the biological methods for controlling red spider mite and whitefly that involve the use of predatory mites and parasitic wasps

- Steve and Val Bradley

BIOLOGICAL pest control is a ‘bug eats bug’ approach that involves the use of natural enemies to help control pests on your plants. There are predators for almost all situations now, not just outside in the garden but also in enclosed places such as indoor rooms, conservatories, greenhouses and polythene-clad structures where edible plants may grow alongside ornamental and tender ones.

Selective organic control

This method of pest control is suitable for organic gardeners and anyone who is reluctant to use pesticides, especially indoors or on plants being grown for food. The predators or parasites are bred to be host-specific, so they will only prey on the insect pest you wish to control and are harmless to other wildlife and pets.

Management not elimination

Dealing with pests biologically is quite different from the traditional practice of aiming to wipe out the whole pest population with one or two applications of a chemical. Biological control is actually about pest management, rather than outright control, so the aim is to keep the pest population at a manageable level, rather than eliminating it altogether. If the pest population disappears completely, the control agent will die out, too, due either to a lack of food or a disrupted lifecycle. So, the aim is to have a balance at all times, with a low population of pests supporting a low population of control.

The two ways biological controls work