Runner Beans not setting

[Geoff]

There have often been discussions here about problems with Runner Beans not setting reliably and I have always said I have never had this problem. I've always put it down to good trench preparation plus a high insect population with my parallel rows of Sweet Peas, Broad Beans and Runner Beans. Well this year so far the set is very patchy. There are masses of flowers, plenty of bumble bees and definitely no shortage of moisture at the roots. A possible problem is that the repeated very heavy showers are knocking flowers and just developing beans off. However, this year I have observed bee behaviour for the first time that I have often read about, they are taking the nectar from behind the flowers. I have for many years grown the variety Red Flame but this year I changed to the often considered best variety Red Rum. I wonder could this be the problem, has the rise of this variety coincided with the development of this behaviour? Has anybody else seen bees doing this and what was the variety? Not easy to photograph but I think you can see what I mean.

Bee Bean.jpg (158.22 KiB) Viewed 7251 times

[oldherbaceous]

Dear Geoff, as i call them, the big black bumblebee, has been doing this to my beans for the last couple of years now, and i grow a mixed variety of beans and they are all attaced.

[Elaine]

Hi Geoff. Sorry I can't help with your problem as I haven't encountered it.....yet.
I just wanted to say what a brilliant photograph of the bee on your runners.
Is it possible for me to "acquire" a copy for myself please?
Cheers.

[Geoff]

Thanks. If you right click the picture you can select "Save Image As" - I nick a lot of pictures off the Internet that way. Alternatively, if you pm me your email address I'll send you the original off the camera which should print better than this one as I reduced the file size for the forum.

[alan refail]

Hi Geoff

Over the years I have noticed bumble bees piercing the base of the flowers as an easy way in. Only smaller bees and other pollinators can get into the flowers and it's perhaps due to the lack of these latter that you have noticed the problem this year.

BTW brilliant photo.

[donedigging]

Hi Geoff,

I am growing two types of runners, White Lady and Celebration. After reading your post I went to watch my bee behaviour.. On the White lady plants, the bees were taking the nectar from the open flower, lots of flowers and beans. On Celebration, less flowers and hardly any beans quite disappointing, but the bees seem too be taking the nectar as you describe from behind. Interesting, would never of looked otherwise.
Next year it will only be White Lady for me.

[Geoff]

Interesting observation. It has often been said that white and variegated flowered beans set better than the normal ones, is this the reason? Perhaps we could compile a list; what variety are you growing, are the bees visiting them normally or taking them from behind? To follow up Alan's post, is anything else pollinating them? Nothing like a bit of scientific observation.

[glallotments]

Great picture Geoff!! I shall be wtaching our bees closely when it stops raining and we can visit the plot

[FelixLeiter]

Interesting observation. It has often been said that white and variegated flowered beans set better than the normal ones, is this the reason? Perhaps we could compile a list; what variety are you growing, are the bees visiting them normally or taking them from behind? To follow up Alan's post, is anything else pollinating them? Nothing like a bit of scientific observation.

I'm growing white-flowered beans this year and they have so far been disappointing. My neighbour is growing red-flowered beans and they seem to be far better overall. I cannot pronounce on the differences being due to any differences in pollination — there are far too many other factors involved (soil conditions, feeding, watering, sowing times and such). The accepted wisdom with runner beans is that white-flowered beans attract night-flying pollinators (mostly moths), while red-flowered beans are attractive to diurnal beasties. I don't know if this has actually been proven. This last week we've been knee-deep in moths at night so maybe my beans' fortunes may improve. If it really is the case, that is.

[Geoff]

I'm a born sceptic - accepted wisdom rarely washes with me - I have to prove or observe it for myself.

[glallotments]

Checked our red flowered runners yesterday and they are setting and no signs of any vandal bees. Maybe they are happy enough with the buddleia and other flowers growing on the plot.

[Geoff]

They'd need brollies today and the immediate future here!

[Primrose]

I'm growing a mixture of Climbing French Beans (Blauhilde & Cobra) and Polestar & Ernoma Runner beans, and due to a labelling mix up they're all planted in together so I suspect in my garden the bees are thoroughly confused. However, they seem to be hopping from one flower to another without any discrimination and so far I haven't noticed any of these visiting from behind. So far, all the red flowers seem to be setting OK.

[Elaine]

Hi Geoff. I was observing the bee activity on my runner beans (Enorma) today and there were lots of bees on the many flowers.
I noticed that the larger bumble bees were all making holes behind the flower and the smaller bees and hover flies were entering the flower itself. As we have already harvested lots of beans and there are many more forming, the crafty actions of the larger bees doesn't seem to have affected the setting...or perhaps the smaller species have got there first!

Whichever it is, it was fascinating watching them.
Cheers

[Geoff]

Not a conclusive set of replies. I have some Red Rum seeds left so next year I shall grow half a row of those and half of something else and see if there is any difference in bee behaviour and setting. Pity when they have grown and flowered like this and are producing so few beans.