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COTTONWOOD LEAF BEETLE
Adult and immature COTTONWOOD LEAF BEETLES.
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| Other |
Leaf beetle |
| Species |
Chrysomela scripta |
| Common Hosts: |
Cottonwood Populus deltoides
Poplars Populus spp.
Willows Salix spp. |
Description |
Adult -- approximately 6 mm long; head and neck black with yellow or red margins; wings yellow to gold with interrupted black stripes.
Pupa -- size of adult; formed within skin of last larval form.
Larva -- size variable, approximately 12 mm long when mature; black head and body with 2 whitish spots on each side. |
Importance |
Large numbers of beetles may occur on an individual tree or a small group of trees. Usually a pest of shade trees and not the forest. Infested trees rarely die from cottonwood leaf beetle defoliation. |
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Adult beetles become active in the spring, feed on the tender foliage and bark. After mating, the females lay their eggs in mat on the underside of leaves. Young larvae feed together and skeletonize the leaves. Older larvae feed separately and consume all but the major leaf veins. Pupation occurs on leaves, bark, or down in the undergrowth. The adults overwinter in protected sites. |
| Number of Generations |
3 or 4 generations per year. |
Signs
of Infestation |
Loss of foliage. Skeletonized, ragged leaves. By late summer, larvae, pupae and adults can be found on one tree. |
Similar Damage |
Drought or other stress factors can bring on a similar needle color change, but none will make the small slits |
Control |
- Natural control factors (predators, parasites, disease, weather) usually keep leaf beetle populations at low levels. Small population flare-ups do occur occasionally. Handpick beetles off trees if possible. Promote tree vigor and health to aid in the recovery from defoliation. Use an approved insecticide for high-value trees or for high populations of beetles. CAUTION: The leaf beetle larvae emit a foul-smelling fluid from swellings on neck when handled or disturbed.
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Bulletin No. 196-A | Printed October, 1983 | Contact the
Forest Health Section 
