Plant Doctor Archive

Spots on bromeliads

SOME of my bromeliads have what look like scale on them, but it's only on the upper surface of the leaves.

THE spots on your sample certainly did resemble scale, but as they were only on the upper surface and there was no sign of young scales I had them checked out at HortResearch. It turns out they are the empty egg sacs of a predatory mite, probably a species of Anystis, which are known as whirlygig mites. They are a good bug to have in the garden as they hunt down and eat some mites which are plant pests.

If you scrape off the empty egg sacs you'll find there's a pale spot underneath where light hasn't been getting through to the leaf surface, but given time that should colour up as chlorophyll returns and photosynthesis becomes active again.

The rural supply company, Williams and Kettle, have a website (www.wilket.co.nz/cms/beneinsects.htm) where you can check out photos of a wide range of beneficial insects, including Anystis, on a variety of plants.

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