The leaves of some of the plants in the conservatory bore the notched marks of vine weevil damage, and the compost around climbing fuchsia 'Lady Boothby' felt looser than it should have done, while last year a mature Impatiens keeled over and had to be salvaged by taking emergency cuttings, which are now cluttering up the kitchen window sill. The real damage done by vine weevils, unsightly as the notches are, is the way their larvae eat the roots of your plants. Chemical drenches are available, although for how much longer who knows, but this year I am going organic. Accordingly I ordered a pack of vine weevil grub-eating nematodes. The theory is that they burrow down into the potting compost and parasitise any larvae they find, killing them and breeding new generations of nematodes to keep up the good work, until they run out of vine weevil larvae and die. Of course really effective parasites don't kill their hosts, which is one reason why the common cold is more common than rabies, but they are in an artificial situation in a pot. In the garden I suppose they just keep going looking for things to feed on, which is partly why I wouldn't use them in the open ground. I am not sure they are entirely host specific to vine weevils, but any kind of larvae in my pots are fair game.
They arrived in a little plastic tray which had to be kept in the fridge until wanted, and looked rather like fresh yeast that had started to go off. I mixed them with water according to the instructions on the packet and watered all the pots in the conservatory, apart from the palm which I am nervous of upsetting since according to my book on palms they have sensitive roots. I watered the auricula pots, and various other pots of primulas since vine weevils are especially partial to primulas, and the houseleeks because I've had problems with them in the past. The instructions didn't say how much water per pot, only that the quantity supplied was sufficient to treat 12 square metres or 160 pots of unspecified size, but I shouldn't think my pots came to more than 12 square metres so I hope they have had a sufficient dose. I watered the pots before the treatment because the instructions said they had to be damp, but didn't follow the advice to water them again since they were quite wet enough already and I didn't want to save them from weevil attack only to kill them by over-watering.
Then I made a diary note to apply another packet in six weeks' time as advised on the packet. I shall report back in due course as to whether they seem to have had any effect.
Addendum: I checked inside the worm bin earlier today and found three of my new charges climbing up the sides. I put them back down on their potato peelings, but when I went this evening to add some more potato and carrot scraps to the bin I found one determined worm trying to escape again. Foolish worms. They should be glad they came to me, when I am not going to use them as fishing bait or feed them to reptiles and only want them to eat potato peelings and breed more worms. I remembered that the worm catalogues had said something about buying coir bedding for your worms, so in the absence of any specially purchased coir I fetched them a few shovelfuls of compost from the most rotted down heap, so see if they liked living in that better than newspaper and potato peelings. I began to remember that last time round worm farming had felt a bit like keeping a hamster: you had to buy it all sorts of expensive accessories and then it died anyway.