Hi Sally and welcome to GoY. Not a stupid question at all yes the flowers do need to be pollinated and no the beneficial insects can't get through the fleece. Do you have a big problem with the the pea moth? We don't use any protection and don't seem to have many damaged pods. You could make a decoction of wormwood and pyrethrum and spray this on the peas to keep the moth away if you do regularly get problems.

Take a look at http://intunewithmoon.findhornpress.com/?p=708 for more information

"Pea flowers are self-pollinating. About two days before the flower even opens, the anthers at the top of the stamen, which are the male part, burst and release the pollen. This sticks onto the stigma and fertilizes the ovary - these are the female parts. In many flowering plants, the stigma will not accept pollen from the same plant and fertilization must occur through other means, such as insect pollination after the flower opens. For gardeners, self-pollination is an advantage as it means more than one type of pea can be grown close together, as cross-pollination will not occur."
From Wikianswers.... so the answer is you CAN use a barrier.

Gosh Bertie - I never knew that! Good thing you checked!

Thanks for the info. I had put some netting on, but then realised that the holes in the netting were bigger than the moth, so plan A would not work. Last year loads of my later peas were affected. I do practice crop rotation but that didn't seem to work, and I try to garden organically, so the news that peas are self-pollinating is very welcome.

Must admit I never knew peas were self pollinating either until I found that article. And I'm always telling everyone that bees are essential to get any crops!
I still think most peas and beans do better with insect pollination though, and runners certainly need it.

Sally did you really have a huge problem with the pea moth? We had very few pods affected. I remember as a child podding peas and almost all had a maggot in them, we just used the peas they had not eaten.

Yes, the later peas last year were riddled and I lost loads. As I have a relatively small plot I can't grow masses of peas to compensate.

I have covered them with fleece now and wait and see what happens with quantity of crop.