Tz—aE ELM-LEAF BEETLE THESIS FOR THE DEGREE OF M. S. \X/alter F. Momfsky 1930 15'1"” ‘ - ‘5‘” '—’ u? 7"" " ’ wan“ ' I I .1 . .p ' '7'- ‘1'. V a. 33?; "MW" H (1293 00998' l6052U W4? _" A ‘ . . 0. ‘EH ‘ ‘3‘va * 3,2“ -. n " .‘.Q ‘1‘ 4:21, f‘l' 4: I- “My; ~. g .. it" .~ ‘ *. AW 51"?“3'33 3” A. 1 iv 3.“' Q- ‘ *:A .i": V_ ~ . ~ }'fi_v i J? ,‘ts «o, 4 ’41 neg A:ol\:.\_h 3"...“ “’3- L w; --: “5‘3 ‘7'»? ‘ ‘ '7 1. w 9-” “a; é” {‘5 " ‘wr .. . “.1 _ . n , i i. . \ ‘i‘gbhlrlp‘y {‘5 «‘{j \w T: _ '. V . . . .‘.', _‘ (Hawk? "31%? ”it" 0:3.13.‘ T\%}‘v; ;‘:£ I 1‘5.ng \uhfczz ‘ :fiffuu iii? " ‘- C i “Hf: H)‘ PLACE N RETURN BOX to remove thin checkout tram your mood. TO AVOID FINES return on or bdoro date duo. DATE DUE DATE DUE DATE DUE MSU I: An Affirmative Action/Equal Opportunity Institution Wanna-9.1 THE ELM-LEAF BEETLE Galeggcella Eggthomelaena (Shrank.) Thesis for Degree of M.S. Michigan State College. Walter F. Egrofsky, 1930. SHEE§|§ s L) «A? (L. ‘1; . 3 1.! INTRODUCTION THE ELM LEAF BEETLE The elm leaf beetle, Galerucella ganthomelaena (Shrank.), is an introduced European insect which attacks elms of the northeastern United States and is gradually spreading westward. It is one of the most destructive pests of elm wherever it occurs. Its presence is most felt in cities where shade trees which have a high aesthetic value, are infested. This insect is active throughout the entire growing season. The adults come from hibernation in April and May and thereafter adults and larvae feed throughout the entire season, the latter feeding on the under sides of the leaves. The elm leaf beetle has thus far been found in two cities in Michigan, having been first reported at Monroe in 1924. The only other infestation now known is one at Rochester, Michigan, reported in 1927. But little damage has thus far been done in the last named city. Observations in connection with this problem have been made by the writer at Monroe, Michigan, during the seasons of 1927, 1928, 1929, and 1930. Studies of this pest, together with methods of control, have been made. The writer wishes to acknowledge the guidance of Professors R.H.Pettit and E.I.McDanie1 in the collection and interpretation of the material herein presented, and to express his gratitude for their kindly assistance and advice. It is also his desire to thank Mr. C. B. Dibble for his assistance in making life history observations, and to express his appreciations to Mr. Ralph Kidder, County Agricultural Agent, and Mr. V. Neuman, City Engineer of Monroe, for their cooperation in the field and in furnishing data concerning the applications and costs of control measures. TAXONOMY The elm leaf beetle was first described as Galerucella luteola by 0. F. Mfiller in 1766. (In 1781 Shrank redescribed it as Qallerucella xanthomelaena). (Fabricus, in 1801, next named it gallerqqella gelatigariaa) and (Harris, in 1852, as Gallerucella gullmariensis). The synohymy of Q, xanthomelaena (Shrank.) is therefore as follows,- Galerucella luteola Muller 1766 galerucella xanthomelaena Shrank 1781 galerugglla gelatinariae Fabricus 1801 Galerg_ella cul mg iensfls Harris 1852 - I‘d. -5- Galenucella an homelaeng is commonly known as the elm leaf beetle, owing to the fact that both larvae and adults feed altogether on the foliage of elms. The name has been officially adopted and sanctioned by the American Association of Economic Entomologists. ELRLY HISTORY The elm leaf beetle is said to be abundant in France, Southern Germany, Austria, and to a lesser extent in Italy, Corsica, and Sardinia. It is not known, however, in these countries as a very serious pest or as a killer of trees. It is believed to have been imported into the United States in 1837 and was first reported as working on elm in 1858 and 1859 at Baltimore, Maryland. DISTRIBUTION Since this time, the insect spread northward slowly, going through New Jersey and finally distributing itself over New England. At the present time it is found in Maine, New Hampshire, Vermont, Connecticut, Rhode Island, Washington D.C., Massachusetts, Pennsylvania, New York, West Virginia, Virginia, North Carolina, South Carolina, Georgia, Florida, Alabama, Tennessee, Kentucky, Ohio, Indiana, Michigan, Oregon, and according to F. C. Roullard it was found to be abundant in 1924 at Fresno, California. It is a curious fact that up to the present time it has never been taken in Illinois. ’ 3 2.: 3.. 5230A wahl de mJPmmmw new; 21m WEI?) mmbarrw @ZE/OImv «7:2 all x h FOOD PLANTS The insect confines itself strictly to the various varieties of elm (Ulmus). According to Dr. w. E. Britten, State Entomologist of Connecticut, the elm leaf beetle prefers European species of elm to American species. He states that the first choice lies with the English elm, Ulmus campestris. Next comes the American elm, Q1333 icana, followed by the Scotch elm, glmus montana, the winged elm, leug glata, the slip-ery elm, glmus £3133, the cork elm, glmus suberosa, and the rock elm, glans racemosa, the choice seeming to be in the order named. Observations made by the writer at Monroe, Michigan, showed that the attack there was most heavy on the American elm, Ulmus americana. The beetle was found working also on Ulmus camnestris and on gimp; racemosa. In this particular locality no other species of trees were found to be attacked. Fig.1 shows the defoliating effects of the beetle on the common American elm. INJURY AND LOSSES The insect was first observed doing serious injury to elms in Michigan in 1924 where its work on the elms at Monroe attracted attention. Followingthe period beginning 1924 and including 1926, it became apparent ‘Z'F ._ l6,- 1 YOUNG? ELM IN ”FOREGROOND A TTAC