Posted: 19/04/2012 at 09:22
All vine weevils are female. The adults are not the real problem. They disfigure leaves by biting chunks out of the edges. They don't fly, and walk about during the night, moving from plant to plant munching and laying eggs. You can only see them at night, and the best way is to lay newspaper under a plant they are attacking and shake it. they drop onto the paper. They lay eggs several times a year, and these hatch out at irregular intervals into the larvae that do so much damage.By the time you notice the symptoms of a larval attack it is often too late. Use Provado Vine Weevil Killer as a preventative, (not Provado Ultimate Bug Killer, which is different). Don't use it on edible crops like strawberries. You need to use it twice a year as the weevils can come back 8 weeks after application when it has worn off.
On edible crops you can use nematodes, but they only work from April to October when the soil temperature is above a certain temperature (can't remember but think it is around 5 C. The only alternative is to remove the plants in the dormant season, wash the roots thoroughly and replant in fresh compost. Remember that if you don't see larvae it does not mean there are not tiny eggs that will soon hatch into larvae.
Because it's expensive stuff, I only use Provado on pot plants, which are much more vulnerable, and on heucheras and sedums in the garden soil. If I am overwintering pots in the greenhouse I occasionally tip them gently out of the pot, check for grubs, and then put them back.
This is a vine weevil adult.
This is a larva (grub)