How do I keep vine weevils off my dahlias?
Tricia Russell, New Forest
ABOB SAYS Vine weevils are all female and need no males, so just one can start a new infestation unaided. They can crawl to almost anywhere but cannot fly and it’s doubtful they can swim. Thus, moating each of your containers is the most effective measure to stop them spreading and multiplying.
Find sufficient ‘saucers’: proper pot plant ones, soup plates or plastic lids that can fit under your containers. Fill these with water and stand the containers above them, each resting on three pebbles or similar.
Each container is now safe from re-infestation or exporting adults but will need individual inspection to remove any adults and or grubs from continuing to feed and breed in it. Having removed any found I’d then apply the commercially available nematode to kill any missed or hatching from eggs. This is best added in warm conditions.