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pole bean leaves - sign of a problem? #801512

Asked July 16, 2022, 4:47 PM EDT

I planted pole beans as in every year, later than usual because of low temperatures in late spring, but all came up very quickly. Soil is very well drained with addition of compost - this year it is Fort V. Bed is well mixed, fairly homogeneous. I did not do Ph tests. I have bee very careful to keep them adequately watered, and they are mulched with straw. On the early (lowest) leaves of a few plants, dead dry areas developed when plants were very small. At present, these spots are dry and brittle. Rest of plant (new leaves) seems OK. IS THIS AN INSECT, DISEASE, SOIL CHEMISTRY, WATER - what? Also see other photo - shows leaves on just a few plants with "crumpled" and pebbly looking areas on both older and newer leaves, IS THIS AN INSECT, DISEASE, SOIL CHEMISTRY, WATER - what?

Lamoille County Vermont

Expert Response

Ed:   Thank you for contacting the UVM Extension Master Gardener Helpline with your question regarding brown areas and curling of green bean leaves.

When I looked at the first photo, I thought that the brown spots looked like sun scald, which happens on young plants. The second photo of the leaf curl appeared to be caused by aphids, however, without seeing the underside of the leaf inside the curl, and no signs of insects or eggs from the photo, that is hard to determine.   I reached out to UVM Plant Pathologist, Ann Hazelrigg and she had the following thoughts:

The first photo of the earlier leaves seems to indicate a sun scorch or watering problem, which happens when the plants are small and vulnerable.  She also thought that it looks like the plants have recovered just fine.

The curling of the other leaves may indicate aphid damage, but she would want to be sure there actually were pests there before recommending any sprays.  If you do not see any pests, she suggests just watching the plants, watering during periods of heat/drought and hope the plants grow out of it.  In this case, a water/heat issue or some other abiotic thing may be the issue, rather than insects.

I am attaching a couple of links to pole bean fact sheets which may be of interest to you.  The first is from the University of Minnesota regarding insects and diseases, and the second is a growing guide from Cornell. 

Quick guide to insects and diseases of beans | UMN Extension

Explore Cornell - Home Gardening - Vegetable Growing Guides - Growing Guide

I hope you find this information helpful.

Susan, UVM Extension Master Gardener Volunteer Replied July 18, 2022, 2:56 PM EDT

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