Two Spotted Spider Mite Flashcards
Two spotted spider mite
(Glasshouse Spider Mite)
Order
Prostigmata
Sucking mites
Two spotted spider mite.
Description
Adults - 0.5mm long.
Pale in colour with two dark blotches on body.
Two spotted spider mite.
Hosts and time of year.
Large range of cultivated plants under protection.
Active in spring and summer.
Active outdoors in late summer.
Two spotted spider mite.
Symptoms.
Early symptoms - silvered/bronzed speckling to surface of leaf, possible chlorosis and bronzing of infested leaves.
Heavy infestation- fine webbing between leaves and shoots; egg cases and cast skins (scurf) may get caught in web.
Adults can be seen with hand lens.
Two spotted spider mite.
Life cycle
Spring to late summer - eggs laid on leaf undersides.
Two nymphal in stars occur (protonymph and deutonymph) before nymph reaches maturity approx 8 to 60 days depending on temperature.
End of season - female turns bight red and seeks hibernation sites in debris and glasshouse frames ( discarded garden canes are favoured.
Egg laying begins again the following spring.
Two spotted spider mite.
Control
Chemical ( acaricides not insecticides) - not suitable, resistance is high and breeding is very high.
Cultural control - regular misting to increase humidity, reducing appeal of the host plants.
Good hygiene in glasshouses especially at the end of growing season - helps check population of overwintering females thus reducing next seasons numbers.
Two spotted spider mite.
Biological control.
Phytoseiulus persimilis - predatory mite.
Red in colour and larger than prey, active forager.
Best results under glass but it is possible to use outside in warmer months.
