Season long control of black vine weevil (Otiorhynchus sulcatus) is now possible thanks to new label recommendations for Exemptor (thiacloprid).
“In recent years ornamental growers have faced increased pest control challenges following many changes in the plant protection market, not least in controlling vine weevil – the scourge of container nursery stock,” says Andrew Wilson, technical manager for crop protection products at Everris. “Subsequent to the loss of Suscon Green and Vi-Nil, recent label restrictions to neonicotinoids have rendered these actives more or less prohibited for use on crops that flower during the year they are treated leaving few stand alone controls available to growers.
“New changes to the label recommendation for Exemptor mean it can now be used to provide up to 38 weeks, or season long control of vine weevil, both under protection and outside. Mixed in to the growing media before use, whatever the temperature Exemptor kills vine weevil grubs.”
Alongside the original 300g/cubic metre rate, providing control of vine weevil for up to 17 weeks, Exemptor has a new 400g/cubic metre rate providing up to 38 weeks control – effectively a full season.
Exemptor binds to growing media minimising the risk of leaching. This is the case even if the end user subsequently pots the plant out in the garden and over waters it – which often happens in the early establishment phase.
Vine weevil can be a devastating problem in both protected and outdoor container nursery stock. With a single vine weevil beetle (all female) capable of laying up to 1000 eggs, if left untreated it can quickly become a devastating pest as the over-wintering grubs feed on plant roots.
Adults particularly like to feed on camellias, euronymus, begonia and rhododendrons while the grubs feed on the roots of most young plants, especially heuchera, primulas, polyanthus, strawberries and sedum – which can cause plants to wilt and die.