Patio problem

I have a fairly large patio made from brick-sized interlocking coloured concrete blocks, about 50mm thick, laid on sand - all properly compacted etc etc - several years ago.

Recently I've been plagued with small flying insects (less than 10mm long) which burrow into the joints and throw up small mounds of sand. I am concerned that they will eventually undermine the whole patio if not controlled.

These insects are not aggresive, definitely not ants and more likely to be some sort of miniature wasp or bee. They seem to be active only when the sun shines.

Can anyone identify these insects from my vague description and suggest a treatment of the area?

 

Your description sounds like hoverflies, is there any chance of a picture please?

 

Sheal,
Thanks for your interest. I don't think they're hoverflies which tend to be larger than my pests and (generally) are solitary whereas my pests are forming colonies.
If they keep still long enough I'll try to get a picture, but it will be difficult.

 

I think solitary bees that have dug in to make nest's , they love sandy soil as so easy to dig out .

more than 200 species of solitary bee in Britain. They are so named because, unlike honeybees and bumblebees, they do not live in colonies. The first solitary bees to appear in the garden, as early as March each year, are the miner bees (Andrena). Similar to honeybees in appearance, they lack pollen baskets on their hind tibiae. These hairy bees make nests in the ground, usually in sandy soil and along paths. The female will dig the nest, stock it with nectar and pollen and then seal it, leaving the young to fend for themselves. Also to be seen later on in the season are the leaf-cutter bees such as the Megachile species, which cut neat circles out of rose leaves and petals to build nests in dead plant stems or sometimes in stacks of old flowerpots. These bees resemble honeybees but can be distinguished by the bright orange pollen brushes under their abdomens. All solitary bees are excellent pollinators and should be encouraged into your garden.

Sorry I wont tell you how to get rid

Spruce

 

@Spruce....Alt has said that the insects are forming colonies so it can't be solitary bees.

 

Spruce,
As Sheal has already commented, my pests are forming colonies. Not in the sense of, say, a common wasp nest where several hundred insects may occupy a single home but where a dozen or so of the spoil heaps may appear on the surface in a 600mm x 600mm area. I don't know if they're connected underground but I intend to find out shortly.

They're very industrious for tiny insects, capable of burrowing into cracks no more than 3mm wide, transporting sand 50mm to the surface and forming spoil heaps many times their own size - all within a couple of hours !

Like you, I won't harm bees; I'm feeling that my pests are probably a type of wasp. This may be coincidence, but at least 2 of the colonies are in areas where I've had ant's nests in the past, but not now. I'm not aware of any bees that predate ants, but wasps will.

 

its not a colony or nor do they interconnect as you will find out , they have all found a place to make a new home , simple as that , just lots of them ..... and they like a soft area to dig just like the ants did.

 

Spruce,
Thanks for the info. I will bow to your greater knowledge of the subject.

 

Spruce,
If, as you say, these insects are bees, do they have a specific name?
Is there any way to discourage them without causing any harm?

 

we would need a photo to tell you which variety as so many in the UK

The only solution would be to use mortar rather than just sand, as you have provided 5 star accommodation with you eg path with sand filling , no plants too shade them out or roots from plants to mess up the tunnels .

In Spring, adult bees emerge, mate and begin nest preparation. The female mines out a cylindrical hole in which to raise her young, and forages on flowers to build up a food supply in the nest. Once adequate food reserves have been collected the female bee deposits an egg in the prepared hole, and the larva that hatches feeds on the food reserves throughout the summer. The mature larva pupates, turns into an adult during the late summer, and spends the winter inside the burrow. These bees then emerge the following Spring to start the cycle again. so whatever you do will have a knock on effect.

What problem is it causing , or is it just unsightly ? How long have you had the path ?
It may be just a case of adding a bag of sand at the end of the summer and brushing all over , the bees will still dig them selves out

Spruce