Broad Beans and Robber Bee damage

[sincerity]

I have grown broad beans without any problems in past years, but this year the plants have been affected by a pest that I have not encountered before. The variety of broad bean that I am growing is 'Bunyards Exhibition'; a proven bean, it appears about waist height and has been decorated with flowers for some three weeks now. From a distance the plant appears to be perfect - healthy and strong, with no sign of pest/ disease. However, on each inspection, I have failed to see any developing pods. On the ground there are a number of flowers, flowers that are intact - i.e. they have the stem end attached, the part that usually remains on the plant and forms the actual bean. On the plant, the flowers appear as they would normally, post pollination - petals shrivelling. If I were to remove a flower from the plant, on inspection, a hole is obvious at the stem end of the flower. This hole is made by the 'Robber Bee', which, instead of entering the petal 'trumpet' and pollinating the flower will instead climb over the flower, cut a hole at the end and extract the nectar from that point. This of course satiates the bee without pollinating the flower. Hence perfect plants in appearance, but useless in yield. I will allow the plants to grow as they do serve as a green manure, but I wonder what impact these bees have on the general bee population. As I always saw lots of bumble bees around the plants I foresaw no pollination problems, but it seems that their efforts were in vain.

[Geoff]

I had the same problem with Runner Beans a couple of years ago but have not seen it on Broad Beans.

viewtopic.php?f=4&t=7432&p=69361&hilit=runner+bean#p69361

[sincerity]

I wanted to add to my earlier comments on the above subject, given what I observed today, on inspecting the plants again. Now that nearly every mature flower ( still attached at this point ) has a hole in the end of it, all bees are now accessing the nectar in this easier way. I added this as it makes bee identification more difficult in that other bees are essentially copying the ways of the Robber bee. The bee is also prone to raid bee hives, robbing their stores. I had not heard of this bee before it affected my beans, I have always bought seeds from Tuckers seeds in Newton Abbot and fortunately they are an excellent source of advice and support.I have been able to call on their help a number of times over the years and am very grateful to them.

[Nature's Babe]

Just wondering if the beans were alone in flower or if there was a variety of things in flower, if there is plenty to choose from the bees will go for the easiest/most suitable. I grew broad bean epicure sown in autumn,, and so far no problem, also in flower in my garden at the moment are a selection of cane fruit, foxgloves, strawberries, peas, herbs, chive and rosemary, land cress, tomatoes, tomatillos, yellow iris, and other flowers. Yesterday I was pleased to note the return of a very tiny butterfly or day moth, no more than 1.5 cm accross,brownish with four yellow dots at the edge of each wing,it's just the right size to access the tiny wee flowers on the thyme.

[sincerity]

@ Nature's Babe
As I garden at an altitude of above 350m above sea level, the gardens regularly get frosts until the second week of June. Last year we had a hard white frost in the third week of June, with frost returning on the 15 August. As our 'summer' is a short affair, I tend to grow most plants on indoors until they are both strong enough to withstand both pests ( being an organic gardener ) and weather issues. Currently my plants are put out during the day and brought in at night. Tonight will be the first time that the plants will stay out in the shed at night. For the reasons above, I currently only have spring onion, peas, parsnip and potatoes in my gardens - being on standby to cover potatoes as and when required. As you can imagine, flowering is later here, with broad beans currently standing out. I have fruit trees and fruit bushes that have been in flower, but that is it. I have no 'ornamental' flowers, only wildfllowers and later green manures which I grow for the benefit of insects. I have put great effort into providing nectar rich plants into the garden for butterflies, bees and other beneficial insects. I am a wildlife enthusiast, with a real passion for our native wildlife, I also have a large collection of bird feeders as I am blessed with such a variety of birds. Back to the point - sorry - most wildflowers are yet to flower. With thanks for your comments, Sincerity.

[Nature's Babe]

Ah, sounds like you do quite a lot for nature, sorry Sincerity, if you go to your profile and put in your area, it would be helpful when we comment to know where you are. Here in the SE it has been quite warm for ages, but no rain and everywhere is pretty dry