Allotment · Pests

Bean Disaster

Yesterday I checked on the bean seeds sown direct at the end of May. A few of the Greek Gigantes climbing beans are at seedling stage and I should be happy to see these cheery little shoots, but all is not well in the bean beds.

Half of these seedlings have come up blind (no growing tip) and distorted.

Bean seedling without a growing tip.

A couple of Borlotto beans appeared to be coming up but stayed almost frozen in time in the same position for days on end. This, along with shoots coming up blind and too many ‘no show’ beans got me thinking. What’s going on?

I decided to poke about in the soil ….

New life cut short. Borlotto bean seedling infested with bean seed fly maggots.

Ahhhh!!! Maggots!!!

This is the work of bean seed fly. Oh dear. My bean growing hasn’t got off to a good start this year.

Bean seed fly larvae (maggots) devouring a Greek Gigantes bean.

Adult bean seed fly looks very similar to the the common housefly, so not exactly easy to spot. Active from May onwards they lay their eggs in soil and are particularly attracted to fresh compost. Whoops!

Bean seed fly larvae (maggots) hatch after a few days and feed on organic matter or their favourite – bean seeds. The maggots eat away at the bean and the roots, so even if beans manage to reach seedling stage they will not thrive and fail to climb up the poles as they should.

Bean seed fly maggots also eat the roots of bean seedlings, they do not thrive and fail to grow.

It has been years since I had a problem with bean seed fly, to the point I almost forgot about it. I have removed all the affected beans and seedlings and checked for maggots in the soil. The few seedlings that have managed to grow to 2-leaf stage I’ll leave for now and observe how they do.

Moving forward, there’s still time to sow more beans which I will do today. This time I will sow into small pots and plant out when large enough to fend for themselves – bean seed fly maggots mostly damage beans and very small seedlings so I’m hoping this works.

Fingers crossed for part 2 of bean growing.


6 thoughts on “Bean Disaster

  1. How annoying. My first sowing came to nothing but I don’t think that this that was the problem, so I sowed some more last week. Fingers crossed that we both do better this time. xx


    1. Thank you Sue. The only time I’ve had this problem was with pots in the greenhouse, so I avoid sowing beans in there now. The fly must be buzzing around our garden, the neighbours all grow veg so it makes sense. I have the pots in the conservatory where it’s nice and warm, hopefully fly free too!


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