Page 32 - AG 7-2011 Revised 2016

Western Lawn Moth adult
Sod Webworm
Tehama bonifatella

Photo Courtesy of UNIVAR

Larva only Sod Webworm
1.Antenna-very small usually 2 segmented 6.Thorax- tubular long body
2.Eyes- ocelli (numerous) 7.Petiole- none 3 6

3.Head- head capsule 8.Abdomen- 8 segments
4.Legs- 3 thoracic legs w/4 prolegs 9.Color- gray to light brown & tan
5.Wings- none 10.Other- larva leaves silk

Life Cycle 4
Adult Grass Moths only live for a short period, but females can lay 60 eggs per
night. Eggs hatch into the larval stage as caterpillars, which feed for 1-2 months “3 Thoracic”
before entering the silken tunnel to pupate. They emerge as moths, living for
about two weeks while scattering eggs each night. 4

“4 Prolegs”

Drawing by Andrew Schaible

The Sod Webworm is actually the larvae of the Lawn Moth. The worm is commonly found at
the base and roots of grasses. They especially frequent meadows, and will create a silken web
of tunnels or tubes near the ground. During the day the caterpillar itself stays in the tunnels,
coming out in the evening to feed. Webworms will eat the blades of grass, but rarely are there
enough webworms to cause large areas of damage.
Webworms are 1-1 ½ inch in length, and have a dark head with light brown or gray spotted
body. The moth itself is whitish, and about an inch in size. It is a poor flyer, and only goes short
distances.

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