Red Spider Mites
They are now the commonest glasshouse pest of all.
Spider Mites are less than 1mm in size and difficult to see without a lens or microscope unless you have very sharp eyes. They often live underneath leaves, and are only active when it is warm. In winter they hibernate either as eggs, or inactive newborns which you can often spot as tiny red or orange shiny dots.
Spider mites can be spotted more easily by looking for the damage . They pierce the leaf cells with their mouthparts and suck the plant juices resulting in discolouration of the leaves and sickly looking growth, and in worst cases the death of the plant. The leaf damage initially results in a fine speckling effect on leaves where the cells have died. The pattern of the mottling varies from plant to plant, so on strawberries you will see brown spots on the underside, and in citrus these develop into yellow patches throughout the leaf. On some plants with tougher leaves the spider mite eats young growth and flower buds and may be even more difficult to spot. Ultimately they may cover the plant in a fine cobweb – they ARE arachnids after all.
You can now see what they look like in action thanks to this video which we have taken in our own nursery. It shows them on a strawberry leaf, in close up at 3 different stages of their life cycle and finally an Aubergine covered in cobwebs.
The main predators for Red Spider mite are Phytoseiulus and Amblyseius. There’s also a predatory midge called feltiella.
Here’s a picture of an Amblyseius squaring up to a Red spider mite – the Amblyseius is on the left.
More information here http://ladybirdplantcare.co.uk/red_spider_mite.html
Amblyseius are also good against broad mites who normally go for strawberries and flowers but which have also made hay with our pepper crops over the last couple of years.
If you need any help or advice please just ask