Scale Insect

There are a whole host of species of scale insect, but I have only seen one species on my collection, and that is Boisduval scale, a known and widespread pest of orchids. It will latch onto almost any orchid, but it has a definite preference for Cattleya and allies, as well as some types of Dendrobium. It is rarely seen on Coelogyne, Bulbophyllum or Phalaenopsis. This pest also resides under leaves, in leaf axils, underneath sheaths, but is also found on pseudobulbs and it particularly likes to hide on the rhizomes of Cattleya. This pest can build up to significant numbers before being noticed so is hard to control. The scale itself is small, only a couple of millimetres in diameter and is generally a yellowish colour with a raised centre. You will also see some that have gone fuzzy at the edges, and these are the nymphs running off to find new sites to feed. You can see the damage they cause in pitted leaves, yellow spotting and distorted growths, especially on Cattleya and relatives. The scales themselves are also large enough to be quite conspicuous unless they are really hiding.