Runner Beans

[aphid]

Hi can anyone tell me why my runner bean leafs are coverd in black soot, i whent to pick some beans and when i looked at my arms they were coverd in what i can only describe as black soot !

[Paulottie]

Sounds like 'chocolate spot.' Difficult to shift once established.... no cure really. eventually even beans have it on and weakens the plant - often stopping production. If it is just in one place and you catch it early it is worth slowing the spread by pruning out and burning.

Better airflow helps....increase your spacings next time.

It is quite common by the beginning of Sept. I sow 2/3rds of my plants in April/May and then a further batch in July for a crop into October.

PS Welcome to the Vine...sorry News is not more positive!

[Two_Sheds]

I didn't know you got chocolate spot on runners, only on broads.

I would've said you've got an aphid problem, which has left you with a sooty mould problem ... http://www.garden-care.org.uk/files/...20Problems.pdf

[Paulottie]

Well you live and learn TS. I include a photo of a leaf. This is not sooty mould and I haven't seen any aphids on the plants at all this year. I have often found this a problem at the back end of the season. Definitely looks like chocolate spot to me.

Oh bother image not showing will try again

Snapfish: Share Photo:Registration

[Two_Sheds]

The RHS says: "Chocolate spot occurs only on Vicia species"

I don't know what you've got Paul It doesn't look like halo blight.

[Paulottie]

MMMmmmm interesting, Not sure I know what 'Vicia' is but I assume that means broad beans? will look later at RHS. might send them the piccie or a leaf or two. My original diagnosis was with the assistance of Hessayon book many years back but now I come to re-examine the book carefully It does say on broad beans.

I was happy in my ignorance but now confused thanks TS.... but it has been a regular problem over the past 10 years...both at home and at the lottie. I have all new sticks this year at wide spacings on the new plot (no beans grown there for several years) with fresh hay and straw in the trench (no compost.) In short, every effort taken to stop recurrence, Definitely looks like fungal prob.

Second sowing in July tip is goodun though (from 85 yo polish chap on lottie)....I have fresh my fresh batch coming into fruit now but the original 20 or so are now slowing up and the spotty thing spreading around. ...not too concerned really as I have been picking 5kg+ a day for 2 months now. Freezer packed and enough credit in at the pub to give myself and mates liver damage.

[yaryl]

I've got exactly the same problem on runner beans, and it has also spread to climbing french beans. Also in trying to tie down what the problem was via the internet I narrowed the culprits to either Halo Blight or Chocolate Spot. The leaves that were on my plants looked exactly like the photo Paulottie posted.

The spots are dusty black/sooty and appear on both the leaves and their stems. It is extremely virulent spreading across my whole group of plants. I have stripped (for burning) all the affected leaves and am left with a pretty much de-nuded bean collection.

If someone can confirm what the problem is it would certainly be helpful!

Yaryl

[Two_Sheds]

I've got exactly the same problem on runner beans, and ... french beans. ...I narrowed the culprits to ...Chocolate Spot.

Runner and Frenchies do not get chocolate spot. Only Broadies do - see my link above ^^^

[Capsid]

Looks like rust to me.

Bean Rust—Diseases-UMass Extension

[Paulottie]

Well done Capsid. I've never heard it called 'bean rust' in this country but it looks right to me (and just like chocolate spot )

Anyhow whatever you want to call it; I've done everything (except sulphur etc.) on the list and still got it..... so erm...?