Beet green pest #480252 - Ask Extension


Beet green pest #480252

Asked August 22, 2018, 6:44 PM EDT

Some pest came in last night and cut the stems of my young, 1 inch to 3 inch, beet greens. It looks like nothing was eaten, just some teenage pests doing damage in the neighborhood. Some were cut at the soil level, but others were cut 1 inch above the soil line. I just got rid of 5 tomato plants because a friend said I had thrips on them. A connection?

Multnomah County Oregon

Expert Response

Thank you for your question,

Most likely, the pest in question is a type of cutworm; perhaps sugar beet cutworm.

The larvae are called cutworms because they cut down young plants as they feed on stems at or below the soil surface.

  • The adults are night-flying moths and do not cause damage.
  • There are also species of climbing cutworms that move up plants and feed on foliage, buds and shoots.
  • Cutworms attack a variety of plants like asparagus, bean, cabbage and other crucifers, carrot, celery, corn, lettuce, pea, pepper, potato and tomato.
Thrips on tomato plants have no connection with cut stems of your beets. Tomato plants can tolerate some thrips injury, unless viruses were transmitted to the plant, by the insect vector.

I iope this helps, 

Jaime Pinero Replied August 23, 2018, 3:17 PM EDT
If it is cutworm, how do I deal with it? Find it in the night and destroy it?  I went out 3 times last night and only saw little slugs, which I don't think cut stems without eating the leaves.  I saw no cutworm.  Also, it looks like thrip damage to some of my beet leaves.  Do you have a low toxic remedy?
The Question Asker Replied August 23, 2018, 3:28 PM EDT
As Dr. Pinero indicated, the cutworm larvae live underground, and only come up to eat the plants at night. Our insect control guide for these follows, with treatment options. However, the chemical products are not available to home gardeners. Both of the Bacillus Thuringiensis varieties are available commercially. Here is the page:

Thrips do not do any harm to beet leaves, so you don't need to control them.
Kristena LaMar Replied August 28, 2018, 2:19 PM EDT

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