The Otiorrhynchi are a kind of weevil: The Black Vine Weevil O. sulcatus and the Cyclamen Weevil O. rugosostriatus are the worst pests on cyclamen.
The damage is done partly by the leaf-eating adult, brown to black in colour and some 6 mm long, and partly by the larvae which feed on the rootlets and main roots at the base of the cyclamen bulb.
The glasshouse climate enables this sort of beetle to develop at any time of year.
Chemical control is not easy, since adults and larvae require separate treatment, and resistance has already become apparent.
Preventive treatment, such as the use of bagged commercial compost, weed control in the surrounding areas and removal of rotting plant material, considerably reduces the risk of infestation.
Biological control is a useful alternative to chemicals.
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