Hi Mike and Florence. Sounds like Hoveflies with many having yellow and black striped bodies. Perfectly harmless of course and indeed most have larvae that eat greenfly off you plants so good to have.

There isn't really a plant that would be effective in keeping insects out of any garden whether they clumsily fly in or actively seek out anything in the garden.

I understand that they pollenate plants. Thought this might compensate the plants a bit for the shortage of bees. I noticed there were far more this year but thought that was because there were simply more plants in my garden.

We noticed that there were a lot more non-honey-bee pollinating insects this year too Silverbell. Isn't Nature clever?

Dear Mike and Florence,

Can I recommend Garden Incense sticks? I use them when I am sitting outdoors and don't want to be pestered by wasps and flies. You can buy them in garden centres. I use the citronella scented ones and the smoke puts off the insects but doesn't harm them at all as they just keep away. You do have to enjoy the scent of incense burning, but you could also try an outdoor candle of course, which would produce less smoke. Worth a try? Best wishes, Karen

As Fractal says, these sound very much like Hoverflies - they need a decent amount of sun to be able to fly, so tend to be seen on hot days through summer. They are charming little creatures and are bee mimics, borrowing the black-and yellow warning colourations, but without any sting.

They would be feeding on the pollen of your Willow, are are also extremely important pollinators of fruit and flowers throughout the land. The larvae are also prodigious consumers of aphids, as Silverbell suggests. Hoverflies are altogether amongst the most useful of creatures you could wish for in the garden, certainly not something to be driven away or discouraged.