Bush bean weird knots

Watch Reply
More
Mark unread Print Skip to new
bluekat76 Ijamsville, MD(Zone 6b) Aug 11, 2005

That about describes it. These knots are hard and appear on the joints of the stems. Just wondering what they are - normal? should I be concerned? These happen to come from the Provider plants.

Thanks -Kim

Thumbnail by bluekat76
Post #1684330
Quote
bluekat76 Ijamsville, MD(Zone 6b) Aug 17, 2005

Now I know someone out there has to know what these are. The plants are not dying but I need to know the why's and how come part of the bean 'knot' mystery.

-Kim

Post #1697985
Quote
DrDoolotz Oxford, NS(Zone 5b) Aug 17, 2005

Hi Bluekat, I did some looking into this (I work at an agricultural company and we do a lot with soybeans so there is a lot of literature around here on bean diseases). Anyhow, I cannot find anything that looks like this on any type of edible beans that is a specific bean disease. I wondered if you have cut into one of the knots. To me, they look like galls, probably formed by some insect that lays its eggs in the gall and then the larvae eat the gall material. I don't think they are a bean-specific gall, but probably just an insect that has a number of host plants and chose your beans.

I found this info on the "lima bean vine borer" which may be relevant.
Lima Bean Vine Borer: The lima bean vine borer (Monoptilota pergratialis) is an occasional pest of the large-stemmed bean varieties. The mature larva (caterpillar) is 7/8 inch long, bluish-green with a tint of pink on its back and has a yellowish-brown plate behind its dark head capsule. It burrows into stems, typically just above or below nodes (that part of the stem from which a leaf grows), and hollows out cavities. Infested stems form galls (a tumor-like swelling) which eventually turn brown and develop a woody texture. Infested plants are weakened and have lower yields.

This sounds like yours - the "knots" you show are locateed at the nodes and they have turned brown and you say they're hard, which suggests a "woody" texture.

Anyway, even if that's not the insect you've got, I suspect they are galls from some insect and that if you cut into them, you might find larvae.

Just my 2 cents!

Post #1699279
Quote
bluekat76 Ijamsville, MD(Zone 6b) Aug 22, 2005

Hey thanks! I think you are right. I haven't gone down and cut into any knots/galls but I will update if I do. I will also be on the lookout for those cats since lima beans are nearby. We are on our last picking of beans so they will be out soon. Strange no one else had them....

-Kim

Post #1710189
Quote

Post a Reply to this Thread

Please or sign up to post.
Back to Forum Homepage

More Vegetable Gardening Threads

Go to all Vegetable Gardening threads
BACK TO TOP