Leaves look speckled, pale colour, underside of leaf looks dusty with masses of tiny mites. Fine webbing is found amongst leaves and stems. Breed in plague proportions in very hot dry dusty situations of midsummer.
Reduce the dryness of the area with water. Squirt water up into the foliage and wet the mulch and soil each morning for 3 or 4 days straight. This will stop their breeding as too damp. Keep moist.
No point in spraying with miticides as mites quickly become immune to each spray. No other insect sprays work either. ‘Eco-Pest Oil’ or ‘Pest-Oil’ will help if can be sprayed under leaves for contact with mites. Water is easiest and works best.
Cause is very hot dry situations in the heat of summer – paving, gravel, stones, pots on verandah or patio, reflective heat off fence or walls are ideal situations when mites populate rapidly. Mulch the soil and keep wet in hot weather, no risk of fungal problems as still very hot and drying atmosphere. If blackspot did show up it is easier to control than mites.