CAUTION: This information was developed for North Carolina and may not apply to other areas.
The elm leaf beetle, Xanthogaleruca luteola, is about 3⁄16 inch long with darker outer margins of the wings and several black spots on the head and thorax. Eggs are about 1⁄32 inch long and are yellow and spindle-shaped. The newly hatched larva is nearly black. Larger larvae are yellow with black bumps. Full-grown larvae are yellow with black stripes along each side. Larvae have a proleg at the rear used for walking. Elm leaf beetle pupae are yellow to bright orange and are usually found in litter on the ground.
The elm leaf beetle was introduced from Europe in 1838 and is now found throughout the United States. Elm leaf beetles overwinter as adults. As the buds on elms start to swell in spring, the beetles begin to emerge. Females begin laying eggs in late May and over the next several weeks, deposit 400 to 800 eggs each in clusters of two or three rows. Eggs are usually placed near the midrib on the underside of leaves. About a week later, they hatch into tiny larvae that skeletonize the leaves by feeding on the lower surface but leave a thin layer of the upper surface intact. The larvae mature in two or three weeks at which time they drop to the ground to pupate under litter or some other shelter near the base of the tree. A new generation of adults emerges in about ten days. Many of the beetles that emerge during the summer months seek places for hibernation early in the season. This movement toward shelter continues until cool weather. In fall, adults may be a nuisance as they crawl into buildings seeking an overwintering site. We have two generations per year in the mountains and three generations in the Piedmont and Coastal Plain.
Elm leaf beetles feed on all elms but tend to prefer English, American and Chinese elms. Zelkova is fed upon less frequently. Damage is most noticeable in landscape trees. The elm leaf beetle is consider the most serious elm defoliator in the United States. Larvae skeletonize leaves which then turn brown and may defoliate prematurely. Adults chew irregular holes in the leaves. Heavily infested trees may be weakened or even killed after repeated attacks.
Few natural enemies feed on elm leaf beetles perhaps because it is an introduced species and left most of its natural enemies behind. Predaceous stink bugs and plant bugs feed on various stages of the elm leaf beetle. Pupae may be killed by a small wasp that develops within. Many insecticides labeled for residential use in landscapes that are available in garden centers may control elm leaf beetles and their larvae if the elm is small enough to be sprayed. In addition to standard chemicals, Heterorhabditis nematodes sprayed on the soil surface under elms at the time of elm leaf beetle pupation can help. These nematodes can be ordered on line. Another strategy is to apply a contact insecticide in at least a foot-wide band around the trunk of infested trees to kill larvae crawling down to pupate. However, migration of elm leaf beetles from untreated trees in the area will probably result in reinfestation. A white fungus, Sporotrichum globuliferum, attacks pupae and adults.
For commercial applications check recommendation in Southeastern US Pest Control Guide for Nursery Crops and Landscape Plantings.
- Elm Leaf Beetle. Dreistadt, S. H. and A. B. Lawson. 2014. UC ANR, UC IPM, Statewide Integrated Pest Management Program, How to Manage Pests in Gardens and Landscapes. Publication 7403.
- Elm Leaf Beetle, Chewed leaves look scorched. Forest Health Protection Rocky Mountain Region. 2011.
- Elm Leaf Beetles - 5.521. Cranshaw, W. S. 2014 (revised). ColoradoState University Extension.
- NC State Plant Pathology Extension Publications
- NC State Horticultural Science Extension Publications
- North Carolina Agricultural Chemicals Manual
For assistance with a specific problem, contact your local Cooperative Extension center.
Publication date: Jan. 13, 2000
Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by NC State University or N.C. A&T State University nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your local N.C. Cooperative Extension county center.
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