Beans’ stem rot could be cold, cutworms

Question: I found a couple of beans in my garden that have been devoured at the base. Could it be some sort of soil-borne larva or possibly a virus? Any ideas would be helpful. I did find one small white worm about a half-centimeter long near the root about an inch away.

It could be a couple of things. First, with cool weather and cool soils, it might be collar rot disease that rots the stem at soil level.

This will happen if you plant beans too early in cold soils. Some varieties of beans are more susceptible to this than others.

The first indicator is that some plants appear stunted and grow poorly.

I usually end up removing these plants and hope the weather warms up.

The other problem can be cutworms. You should be spraying or dusting the soil surface around these plants with Dipel or Thuricide, an organic pesticide. This is the time of year you should be doing that anyway for a variety of pests in the vegetable garden.

Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at extremehort@aol.com. Visit his blog at
xtremehorticulture.blogspot.com. For more gardening advice, see the Home section of Thursday’s Las Vegas Review-Journal.