Not entirely sure Jane,but I think your OH is correct..They look like slow release fertiliser pellets to me..Vine weevil grubs are shaped like a small letter C ,and are white..at least mine are .:o)

:)

I've seen vine weevil grubs and they are fat, squishy, not quite circular and very white. I think your OH is right.

Yes I know the grubs are white because I had them in my primulas - but are these the eggs because I had something similar in the primula pots - when you squash them they have like a milky substance in side of them - Jane

They may well be vine weevil eggs, specially if there's a liquid inside when you squish them. Most vine weevil eggs are brownish, and less than 1/16th of an inch, but we do have other breeds of vine weevil, not sure what their eggs are like. Here's a link to the RHS page on vine weevil generally, giving a description of the eggs (lower down)

https://www.rhs.org.uk/advice/profile?PID=234

but this link might be more useful

http://www.clockhousenursery.co.uk/garden-tips

I would have said slow-release fertiliser capsules.

Try catching a few to see if they hatch. Nonetheless, go with new potting soil for your begonias.

Thankyou all for your comments - I think I will certainly keep these newbes away from my flamboyant begonias - I will let you know the outcome !! - Jane

Janelloyd, I should have said this - the second link I provided shows images of vine weevil eggs and of fertilizer capsules so you might be able to tell from looking at those pics...

Bamboo - I think you are right - well I am hoping you are right - I don't have a very forgiving nature towards weevil grubs since they crunched their way through my primulas - Happy Gardening and enjoy your day - Jane