Pest Management Practices for Home and Landscape: Leaf Beetles Printable .pdf version (2 pages) Several beetles feed on shrubs and shade trees in Mississippi. Some of these are June (May) beetles (JB), Southern masked chafer (SMC), elm leaf beetle (ELB), and cottonwood leaf beetle (CLB). The JB and SMC are similar in development and feeding habits, but the June beetle is a much smaller beetle. The ELB and the CLB are similar in development and feeding habits. June Beetle The adult June beetles are brown to brownish-black beetles about 1/2 to 5/8 of an inch long. Sometimes a slight reddish tinge is just behind the head. The adults are active at night. Males are attracted to lights, but lights are not as attractive to females. Adults emerge from the soil about the middle of May and earlier in south Mississippi. This is about the same time leaves on shrubs and shade trees are out fully. The beetles feed on roses, a number of trees (oak, hickories, and others), and some on beans and potatoes. They eat irregular to roughly circular holes in the leaves. They rarely feed enough on large trees to do any damage; however, in years where beetle numbers are high, they may damage young trees and roses. If you notice signs of leaf feeding but cannot find the insects, remember that these beetles are active at night. They may be resting in the mulch at the base of the plants in the day or on leaves of large trees. Inspect your plants in late evening or at night if you suspect these beetles. Life Cycle (JB) Eggs - deposited in the soil and hatch in 2 to 3 weeks. Larva - feeds on grass roots for 2 to 3 seasons. Pupa - formed about midsummer of second or third year. Adult emerges from pupa case in late summer but remains in the soil 6 to 8 inches deep until the next spring. Adult - emerges from the soil in late spring or early summer.   Elm Leaf Beetle The elm leaf beetle is found in all sections of the country where elms are used as shade trees. This tree is apparently the only host plant for this insect. The adult is a yellowish-green beetle about 1/4 of an inch long with black eyes and yellow antennae. The outer-wing covers usually have a black band along the outer sides (sometimes indistinct). Mature larvae are about ½ of an inch long and yellow green with two black stripes down the back. The adults eat small, roughly circular holes in the leaves. The larvae usually skeletonize the leaf from the underside. The main host for the cottonwood leaf beetle (CLB) is the cottonwood tree. This beetle is about the same size and color as the ELB; however, the back is covered with more black markings.   Life Cycle (ELB) Eggs - deposited in double rows on underside of leaf. Appear yellow; hatch in about one week. Larva - feeds for 2 to 3 weeks. When ready to pupate, they congregate in large numbers on the trunk or at the base of the tree. Pupa - lasts about 10 days. Adult - overwinters in buildings or under loose bark. It flies to elms in May or June. Each female may lay 400 to 800 eggs. Generations/year - two to three. The amount of defoliation caused by leaf-feeding beetles often does not warrant control on large trees. Even if the percent of defoliation is moderate to heavy, control is hampered by the size of the tree and the type of equipment needed for good coverage. Plus, hardwood trees are hardy, and one or two years of defoliation will not hurt them. If roses or young trees are involved, control is often justified. If spraying is justified, the following materials can be used. Read the label on the product of choice for safety and disposal information. Material Rate per gallon of water Sevin 21.3% 4 teaspoons Orthene 9.4% 2 to 3 tablespoons     Do not use Orthene on American elm, flowering crabapple, sugar maple, red maple, cottonwood, redbud, and weigela. Sevin damages Boston ivy, Virginia creeper, and maidenhair fern. Enlarged drawing of June (May) beetle. Actual size of the adult is about 1/2 to 5/8 of an inch. Enlarged drawing of elm leaf beetle. Actual size of the adult is about 1/4 of an inch. By Dr. James Jarratt, Extension Entomologist. Information Sheet 572 Mississippi State University does not discriminate on the basis of race, color, religion, national origin, sex, age, disability, or veteran status. Extension Service of Mississippi State University, cooperating with U.S. Department of Agriculture. Published in furtherance of Acts of Congress, May 8 and June 30, 1914. Joe H. McGilberry, Interim Director (rev-500-8-01) Copyright by Mississippi State University. All rights reserved. This document may be copied and distributed for nonprofit educational purposes provided that credit is given to the Mississippi State University Extension Service. Visit: DAFVM || USDA Search our Site || Need more information about this subject? Last Modified: Wednesday, 11-Feb-09 14:06:33 URL: http://msucares.com/pubs/infosheets/is0572.htm Mississippi State University is an equal opportunity institution. Recommendations on this web site do not endorse any commercial products or trade names.