Produce > Pests & Diseases

Mystery of the missing blackfly on my broad beans

<< < (3/4) > >>

I got normal blackfly numbers on my broad beans, at the normal time (ie. after they are more than 50% tall) , and the ladybirds arrived a few weeks ago so most of the fly have been polished off now - nothing unusual there either. The beans were sown in November. I count this as a lucky escape.

My indicator for a bad year is when the blackfly move onto the baby beans in a line down the crease - it didn't happen this year, so it's a middling infestation - that means I don't need to wipe the beans or my hands when picking.

I think the ladybirds are the key players here (especially the larvae - because they stay put - though the ladybirds seem better against ants - presumably they can't be mobbed) - I normally try to sow in both October & November (white seed) and also March (green seed) and I almost always find one sowing gets a light infestation (when the ladybirds arrive soon after the blackfly), and one gets a medium (when they are a bit late) and one gets it heavy when they are very late - but it's impossible to predict which sowing will get timely or late ladybirds, and that's why I do at least these 3 sowings, sometimes February too.

Since I am in Outer London I'm not sure why I've bothered with the white-seed beans - I will be trying the better-flavoured green-seeded types for all 3 (or 4) sowings next year.

Has anyone in the SE had any experience of how well green (or pink) seeded types cope with an autumn sowing?


PS. If there's "green" in the name they will be the better kind. "Crimson flower" broad beans are also green-seeded, but unfortunately the breeding for appearance has had its almost inevitable effect of knocking out the flavour - the baby went out with the bathwater.

My plots are on quite an exposed site on the edge of Oxford and I've found that if I start my broadies in the autumn out there, they just get blown away, frozen off, washed away, or one of any number of winter malaises. If I start them in pots at home in the autumn, they tend to get too tall while I wait for vaguely sensible weather to plant them out, and get blown horizontal as soon as I do so. This year I started them in late Jan, I think, and have the best crop I've had in years, from Aquadulce Claudia, Karmazyn (red beans) and Dreadnought, without them succumbing to anything.

Dunno how helpful that is as I don't know what your plot is like, but I've tried. I'm good at trying, my missus says I am always trying!

Tee Gee:
I used a method that worked for me, and I was rarely affected.

The method  was quite simple; I counted the number of flower trusses there were and when they got to 5 sets I removed the tip of each plant. Through trial and error I discovered that this worked, e.g. when I  allowed six trusses (or more) to flower  I invariably got an infestation, but with five or less trusses; at worst I usually only got a few or none at all!

So I guess the moral is; getting fewer is much better than getting none!

I was told that you should put broad beans in the freezer before you plant them and that reduces the amount of black fly.  Also I prefer masterpiece green longpod which seems to have few flies.
And ants tend to farm the aphids so if you can get rid of ants you get rid of the flies.
We have so many morning frost in April.  Hardly a morning without one.  Never seen that before, normally by April frosts are becoming scarce.  Only one of my early sown courgette plants survived even with all my frost protection methods.
I left bottles over my broad beans but then managed to cook them.  But to my surprise they sprung up with several new shoots and I have a bumper crop, and also very few black flies.

I think putting in the freezer is thought to deal with bean weevils in the seed? I can't see that it could affect blackfly which come onto the plant when it's in full growth?


[0] Message Index

[#] Next page

[*] Previous page

Go to full version