VINE WEEVIL QUESTION AND ANSWER
Article by David Marks
Our main Vine Weevil article can be found here. But sometimes our readers ask specific questions which are not covered in the main article. This page lists their comments, questions and answers. At the end of this page there is also a form for you to submit any new question or comment you have.
COMMENTS / QUESTIONS LEFT BY OUR READERS
|Date: 28 July 2018
|From: Shirley B
|QUESTION: I moved into my new build house 18 months ago. Now I find all the outside plants provided by the builder have been almost devastated by vine weevil and so have the other people garden plants. I rang the gardener who insists I must have planted a new plant at some time I haven’t planted any. Who is to blame please?
ANSWER: It’s imposssible to say with 100% certainty. However if what you say above is true, it is extremely likely that the gardener has introduced vine weevil to both your garden and your neighbours.
|Date: 14 July 2018
|QUESTION: I have just tried to use miracle grow soil to pot some begonias and in the soil there are round white ball like objects about 3mm in diameter when I tried to crush them the seemed to be full of some kind of liquid. Are they vine weevil eggs?
ANSWER: I have never used Miracle Gro before so I can’t be absolutely sure. However my best guess is that they are tiny fertiliser pellets containing small amounts of liquid fertiliser designed to break up over a period of time. I had a quick Google and found this page where you can compare:
|Date: 21 June 2018
|QUESTION: I have a vine weevil infestation in my courtyard (all plants are in pots) I do a search for and destroy adults and having checked the soil I am finding eggs rather than larvae. I have ordered some Nematodes to treat the problem, but is there any chance of success while the vine weevils are in egg form? Also I used Scotts bug clear VW killer two weeks ago in some of the pots, will this kill the nematodes when I use them?
ANSWER: Vine weevil nematodes only attack the larvae, they do not attack the egg stage. Quite how long it takes for an egg to turn into a larvae I am not sure but I think it is a couple of weeks.
I doubt that Scotts Bug Clear Vine Weevil Killer will kill the nematodes. Scotts Bug Clear Vine Weevil Killer firstly works as a systemic killer and the nematodes will not eat the roots of the plant so therefore will not be killed. It also works as a contact spray, but the nematodes are mainly below the soil surface so won’t be killed.
You would need to check with Scotts to be absolutely sure of that.
|Date: 22 April 2018
|QUESTION: What is likely to happen if I put old potting compost infested with vine weevils on open garden?
ANSWER: There is a distinct possibility that it will attack nearby plants. I would suggest disposing of the soil in your garden waste bin.
|Date: 19 April 2018
|From: Patricia C
|QUESTION: I found vine weevil grubs in pots. Do i have to get rid of the plants in them?
ANSWER: No, if the plants have life in them you may be able to save them. You need to wash the roots in water to remove every trace of soil on them and then replant in new compost.
|Date: 10 January 2018
|From: Not known
|COMMENT:I must share my experiences with the vine weevil. They really are devastating creatures. For years I had growing on the patio a lovely strawberry Hapil, but one year it suddenly stopped growing. After checking the soil I found it to be infested with hundreds of those grubs like the picture on this page. The plant was well dead. The weevils had done the same to a blackberry plant of mine a few months previous.
Also that same year my blueberry Reka which I’d been growing beautifully for a decade suddenly fell ill, looking sickly with no new growth. Upon inspection of the soil I found a few of those maggot like things. So I removed the plant from the container(50 litres) and was horrified to see that the whole root system was covered with these things. The plant as my strawberry was dead too.
Weevil maggots seem to inject poison into the plant as they feed and leave the plant’s root system looking a horrible orangey brown dead. Nasty creatures indeed. My solution was to start planting chives and lemon balm in my pots to deter their egg laying and put gravel or shale over the soil surface. Seems to have worked for now.
|Date: 4 June 2017
|QUESTION: Hello, I have vine weevil in my pots, I have used nematodes once so far this year. I now have numerous pots with just soil left after taking out the dead plants. If I leave these pots unplanted – how long would have to wait untill they are weevil free!? am guessing no plant – no food for them?
ANSWER: I would guess you are correct but soil by its very nature contains decaying matter. For me, I wouldn’t take the chance. I would empty the soil, clean the pots scrupulously, leave them dry for a month, re-fill and then then replant.
|Date: 31 March 2017
|From: Carole H
|I’ve had a massive problem with vine weevils in the garden because it was a neglected garden until I moved here so the evil things were way out of hand. I have finally managed to get the upper hand but it’s been an expensive, long job trying to get rid of them. After trial and error I’ve found the best way is to use a combination of actions.
As of now, late March, I go out nightly for half hour with a torch and a jar of soapy water and pick off as many of the weevils as I can find and drown them in the soapy water. If you don’t use soapy water they can crawl out of the jar. They are not difficult to see with a good torch, I use a head torch so both my hands are free.
In mid April and again in September I use nematodes on the garden. I only target their favourite plants/shrubs now because it was proving too expensive to treat the whole garden. I pot up decoy plants in troughs, Primulas, they love them and place them around the garden. I treat the troughs with Provado vine weevil killer because Provado lasts quite a few months so any weevils lured there to lay their eggs don’t have a cat in hell’s chance.
I don’t really like to use Provado because of the bees but if it’s only used when there are no flowers on the Primula the risk to the bees is negligible and by the time the flowers come in spring the chemicals have dissipated over winter.
I use gravel on top of all my other pots and if I suspect weevil grubs I treat the pots with nematodes if there are flowers and Provado if there are no flowers. If I find weevil grubs in pots in winter I use Provado because the nematodes don’t work in winter anyway.
This year spring has come early and so have the weevils but this year on the past couple of night patrols I have only caught a dozen or so, I was catching hundreds in a half hour or so before, fingers crossed I’m finally winning.
|Date: 8 March 2017
|QUESTION: I HAVE TWO RAISED DEEP SALAD/TOMATO BEDS IN A LARGE UNHEATED GREENHOUSE IN DEVON. THE SALAD HAS BEEN EATEN BY VINE WEEVIL THIS WINTER(AS IT WAS THE PREVIOUS AND I TREATED IT WITH NEMATODES IN THE SPRING BUT ONLY ONCE AS I THOUGHT THE PROBLEM WAS RESOLVED).I AM CONSIDERING DRENCHING ALL THE GREENHOUSE THIS SPRING INCLUDING GRAVEL BENCHES AND POT PLANTS. WHAT WOULD BE THE OPTIMUM TIME?(I WANT THE HIGHEST TEMPERATURE FOR IT TO WORK WELL BUT TO KILL LARVA BEFORE THEY TURN INTO ADULTS.
ANSWER: For a spring treatment the soil temperature should be above 5C, probably the optimum temperature 10C. If you live in Devon and the plants are in a greenhouse, I would suggest the late March to early April is the ideal time. You could buy a cheap soil temperature guage to check the soil temperature.
If the problem is bad, I would also suggest a second treatment in mid September.
|Date: 22 February 2017
|From: Margaret M
|Newcastle upon Tyne I have just checked my two potted bay trees and one has had its leaves eaten around the edges. I have dealt with vine weevil in the past (not in this garden) but not on the bays. I took the usual precaution of protecting the roots against frost-now these vine weevils have raised there horrible little heads!.
|Date: 30 December 2016
|QUESTION: It’s the end of December and I have just noticed that some of my potted standard bay tree leaves have ragged holes on their sides. The bay tree was repotted with fresh John Innes No.3 compost back in May of this year. I have been putting a fleece covering over the tree on frosty nights and it hasn’t been overwatered.
I have read your advice on vine weevil damage and am afraid that this is what I may be dealing with. What can I do to protect my bay tree over the winter? It is too late to apply nematodes and I am worried that by April of 2017 the roots of my tree may have been destroyed.
ANSWER: The adult vine weevils which cause the leaf damage are only active from April to August. If the leaf damage occurs outside of that time frame (assuming you live in the UK) then vine weevils are not your problem.
Aside from waiting until the nematodes are available to buy you only have two possible courses of action at the the moment. The first is to try and drown the grubs as suggested in the question / answers below. The other course of action is to remove the plants from their pots, remove as much soil as you can and then repot with new soil. If it was me, I would try drowning them. Best of luck.
|Date: 24 October 2016
|QUESTION: I have a problem with vine weevil. Is it worthwhile putting gravel on top of pots when planting? We plant up puts in October with bulbs pansies, heathers etc and in spring with summer stuff. Should I put gravel on the top of pots both times or just in spring?
ANSWER: Placing gravel on the compost surface makes it more difficult for the vine weevils to lay eggs so it is worthwhile. If you place a 2cm layer of gravel on the surface in early April 2017 it should last a couple of years. Vine weevils lay eggs from May to early August.
|Date: 7 July 2016
|QUESTION: I put all of the pots in the water foliage an all weevils and slugs came up to the top the weevils cant swim but they will move there legs to crawl to the sides (how can i find the eggs)?
ANSWER: I believe the eggs will be drowned so there is no need to find them.
|Date: 23 June 2016
|QUESTION: Could you put the plant and pot in a water butt for a few hours or over night to drown the vine weevils?
ANSWER: I haven’t tried this but I have read of it being done. The advice seems to be to submerge the plant (not the top growth) in water for 48 hours. This is not long enough to damage the plant significantly but apparently it does drown the vine weevils.
I suspect that this might not be the end of the problem because the adult vine weevils continue to lay eggs over two to three months. But it is certainly worth a try.