What Ms Watkins wants is a three-pronged weapon: a foolproof method of trapping the adult weevil, combined with a wash that will destroy the eggs, and a more effective treatment against the larvae which eat lustily through the roots of succulents, cyclamen, bedding plants, fuchsias, primulas, bulbs, especially when grown in containers.
Unfortunately, nothing of that sort exists. The best control is the biological one but, as Ms Watkins points out, the nematodes only work in exactly the right conditions. And they are expensive.
Soil temperature is one important determining factor. You can use the nematodes in April/May or September/ October but only when the soil temperature is more than 12C. The earth also needs to be moist and kept that way for at least two weeks after you have watered in the nematodes.
They enter the vine weevil larvae through its skin and give it a nasty form of blood poisoning. When the grub dies, the nematodes are released to find another victim. A pack sufficient to treat five square metres costs pounds 10.95. If you are attacking vine weevil in pots and tubs, use the mixture at half-strength. Get the nematodes from Defenders Ltd, Freepost, PO Box 131, Wye, Ashford, Kent TN25 5BR (0233 813121).Reuse content