Scale insects

in : Problems: Fruit & nuts

Symptoms

Plants are infested with tiny, sap-feeding, scale-like insects packed around the stems and leaves.
Find it on a wide range of plants, house plants, greenhouse plants
Time to act all year round

Problem categories

Overview

Tiny sap-sucking scale insects. They are 1-6mm long, and their whitish, grey-brown shells are covered by protective, waxy scales. The insects don't cause too much damage unless they are present in huge numbers, but some excrete an unsightly, sticky, sugary substance (called honeydew) which encourages the growth of a fungus called sooty mould. Early summer is the best time to tackle the problem, when the newly hatched insects are crawling around looking for a place to feed and settle.
Solution
Plants are infested with tiny, sap-feeding, scale-like insects packed around the stems and leaves.
Organic
First try to remove them with your thumbnail. If there are too many, use an insecticidal soap spray. Alternatively, leave them for the birds to pick off. In a greenhouse, use the parasitic wasp, Metaphycus helvolus, bought by mail order as a biological control.
Chemical
Use an insecticide containing imidacloprid or thiacloprid in early summer when the insects are more vulnerable.

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Talkback: Scale insects
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spottyleopard 24/11/2011 at 15:27

I use broad sticky tape to remove scale insects - more efficient than a thumbnail.

Ants farm scale insects, so get rid of the ants and the problem will be reduced. To keep ants off a balcony organically (this may not work in a garden!) stamp on every ant you see. Ants will not continue to send workers if a percentage fail to return. This really works.

ILOVEBEES 24/11/2011 at 15:29

Before using thiacloprid, imidacloprid, acetamocloprid or any other neonicotinoid pesticide, I recommed visiting the Buglife website, to read their report summarising independent research on neonicotinoids. They kill bees & other non-target insects - eg. butterflies etc. Miniscule amounts impair the ability of insect to function resulting inevitably in death. Also, seek out the fact sheets from the US environment agency -you may get a shock! We used to manage without them & can now.

Jennifer Chetwynd 01/02/2012 at 14:18

control of scale insects needed on a decorative orange tree. Any ideas?