Plant Doctor Archive

Bugs on orchids

MY orchids are infested with small white scale with a black centre, no bigger than 3mm. Can you tell me what it is and how to get rid of it?

THERE are many different types of scale and it's often difficult to identify individual types. Luckily, they are relatively easy to control with oil sprays like Conqueror, Clear White Oil and Eco Oil.

To avoid damage to blooms, don't spray during flowering. You'll probably have to apply several sprays over a period of time to get full control and then again once or twice a year to keep them from becoming reinfested. A spray early in spring is good at preventing problems later.

Make sure you thoroughly cover both surfaces of the leaves and the pseudobulbs so the oil solution can do its job of smothering the scale. A few weeks will probably pass before the dead scales drop off, so don't despair if it seems nothing is happening for a while.

Systemic insecticides like Target and Confidor will also do the trick - follow the label recommendations.

Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.