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julieann_grow

Rust prevention

julieann_grow
16 years ago

My pole beans (Fortex, asparagus beans and Roma) already have rust and they just reached the top of their poles.

This is in a new area where no beans have been before.

What do ya'll use to prevent/slow down rust? (Organic suggestions only, please).

Comment (1)

  • zeedman Zone 5 Wisconsin
    16 years ago

    Julieann, I am surprised at that list of varieties... in my experience, "Fortex" and some Romano-type beans are very rust-resistant. In fact, in a very wet year, only 2 out of 9 beans were not infected... "Fortex" and an heirloom Romano, "Garafal Oro". Asparagus beans (I assume you mean yardlongs, not winged beans which also share that name) have also never been rust infected for me. Is it possible for you to post a photo?

    I can only make recommendations as to preventive measures; my attempts at organic rust control (once infected) have been less than effective.

    Rust is airborne, so your beans can get it even on new ground. However, it is also soil-borne in areas where infected beans were previously grown; the use of a straw mulch to prevent rain splash can be helpful. Apply it after the beans have their first true leaf - too early, and it can shelter insects that will kill the tender seedlings. Beans really dislike mud on their leaves, once I apply the mulch I spray the leaves clean, and they literally turn green overnight.

    Moist leaves & over-crowding promote the spread of rust, so if you live in a problem area, you need to encourage greater air flow to keep the leaves dry. I grow an heirloom pole shell bean that is very rust-susceptible (I love it anyway) so I give it wider spacing, 12" between plants. If there is a sustained period of cool wet weather, rust will still be a problem... but not as severely, and with minimal impact on yield.

    Incidentally, I experimented with several spacings for both "Fortex" and asparagus beans (a.k.a. yardlongs). For "Fortex", 6" spacing (or 2 @ 12") was optimal. For yardlongs, I use 12-15". This may seem like wide spacing... but the plants branch to compensate, and are more vigorous.

    You may have heard that you should avoid touching bean plants when wet... if the plants have rust (or any other disease), or if you want to avoid worsening the problem, that is good advice. Even when plants are dry, harvest the most heavily-infected plants last.

    Avoid the use of overhead irrigation on beans, especially just before nightfall - don't put them to bed wet.

    Now, I know that this last piece of advice ranks high on the "GW most hated" list... but you might want to check with your state's Cooperative Extension. They could help you to verify that rust is the problem, and might be able to recommend disease resistant bean cultivars for your area.

    I will leave you with a link. Asian soybean rust has become a problem in the Southeast, and can infect many bean species. Since two different species are infected in your garden, if you live in that area, it could be a possibility.

    Here is a link that might be useful: Asian soybean rust

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