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Extremely small green worms #676372

Asked 2020-10-17 20:51:15

These worms are about one quarter inch long and descend on a single silk line in September and October. They eat small holes in the elm leaves. What may they be

Clay County Missouri

Expert Response

It may be an elm sawfly larva, (Cimbex americana). Management of elm sawflies in MN is rarely needed.  The following site has more information about sawflies.https://extension.umn.edu/yard-and-garden-insects/sawflies#elm-sawfly-1041964

Pat Mack Replied 2020-10-17 21:09:51
These worms are grass green without any markings



On Sat, Oct 17, 2020 at 4:09 PM, Ask Extension
wrote:
Wm E Gillespie Replied 2020-10-17 21:24:04

Cankerworm is the common name for several destructive caterpillars in the measuring worm family. Fall cankerworm is a looper caterpillar that can range from light green to dark green to black.  Fall cankerworms are about an inch long when full grown. Mature larvae descend from trees on silk threads to pupate in the soil. They emerge as adults during periods of freezing temperatures to mate and lay eggs on host plants. There is one generation each year.

https://extension.umn.edu/yard-and-garden-insects/spring-and-fall-cankerworms

Pat Mack Replied 2020-10-17 23:27:40

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