European red mite (ERM), two-spotted spider mite (TSSM), are potentially serious orchard pests.
Mites are very small and are best counted and identified with a microscope. Female ERM are bright red while males are a dull greenish-brown. Both have white spots and six to eight hairs. Two-spotted spider mites are pale green to straw coloured, with two dark spots on their backs.
Plant Parts: Leaves - Speckled when lightly infested, bronzed when heavily infested.
Fruit - Size and colour may be affected if mites are numerous for a long period.
Season: Overwintering eggs occur in clusters on roughened areas of bark on twigs and smaller branches, often on the undersides of fruit spurs and at forks of small branches. Eggs hatch during spring, and young mites feed upon the opening flowers and developing leaves. The mites continue to feed upon leaves during spring and summer, increasing in numbers in response to warm temperatures.
Symptoms: High populations of two-spotted spider mites produce stippling on the top of leaves, and characteristic webs on the underside of leaves.
ERM and two-spotted mites remove sap, chlorophyll and nitrogen from leaves. High populations cause a condition called "bronzing". Silvering of leaves can also occur.
Prolonged feeding, particularly if populations are heavy in early to mid-summer, leads to a reduction in shoot growth and fruit bud set the next year. Fruit colour, soluble solids, firmness and size can also be affected.
Control: If your Fruit Salad Tree has a mite infestation then on this occasion we would recommend watering the affected plant from above, remove and destroy badly infested leaves. Encourage natural enemies like ladybugs to your garden. You can use natural soaps/oil based sprays to combat this spidery little pest that can be purchased from your local nursery. Miticides can be effective against mite eggs, nymphs or both. Apply Agricultural Oil in early spring to control overwintering ERM eggs.
Prevention: Conditions that are favourable to this insect include: dusty areas in and around your home garden; hot, dry conditions, and excessive use of sprays that reduce the number of beneficial insects. Try and limit the use of broad spectrum insecticides to prevent this from happening.
References: British Columbia Ministry of Agriculture, OMAFRA, Orchard Plant Protection Guide 2020-21, Utah State University, and the FST team.
