Red Spider Mite or Two-Spotted Mite
The red spider or two-spotted mite (Tetranychus urticae) is not a spider, even though it may spin a fine spidery web in the leaf axils that is used for getting around. They feed on plant sap and cause leaves to look a bronze-brown-yellowish coloured and become papery dry before they fall off. A heavy infestation with near total leaf loss will take a long time to recover after eradicating the mite; or it may be fatal. A hot dry environment encourages breeding; at 30°C a single mite may produce 13 million offspring during its few weeks’ lifetime, so it is seen in the hot summer months.
The easiest way to recognise Red Spider mite is by the yellowish/bronzed, papery leaves and the actual mites in the fine spidery webs between axils and stem. A magnifying glass is almost essential to make a firm diagnosis. Often, noticing the bronzed leaves it is already too, as a red spider mite infestation spreads readily and is not easy to eradicate in closed environments.
Using a systemic insecticide, strictly according to the manufacturer’s instructions, does help in controlling red spider mite. However, spider mites are becoming more prevalent each year and one reason is that they are becoming immune to sprays. In addition, continuous spraying also eliminates natural predators.
Since surface debris and mulch host spider mites, cleanliness and regular spraying will help to keep them under control.
This non-toxic solution needs to be applied at least weekly for any chance of success:
Chop up 1 whole garlic bulb and 4 chillies, add some water and simmer for 2 hours. Add a dash of detergent or oil and let the mixture cool. Store for 24 hours before spraying the undiluted solution.