6 The Eueopean Elm Scale 



Elm Scale which threatens their serious injury. This is an insect 

 problem which demands a prompt and practical solution. 



The purpose of the present bulletin is to state this problem fully 

 and to suggest means for its solution. "We have chosen pictures as the 

 readiest means of stating the nature of the pest and its relation to the 

 tree in a way which the average man can understand. "We chose 

 spraying with lime-sulphur in the winter as the most promising means 

 of destroying the half-grown insects ; a careful study of the problem has 

 nearly convinced the writer that better results can be attained by far 

 simpler means in this vicinity. It is even likely that if it should prove 

 necessary to spray the elms every year or two with lime-sulphur in 

 order to keep the Scale under control, human nature will play the 

 same part that it did in the destruction of apple trees which had be- 

 come a source of more annoyance than profit. 



THE NATURE OP THE PEST 



As the common name indicates, the European Elm Scale is an 

 insect introduced into this country from Europe. It was first observed 

 in America at Eye, New York, in the year 1884. It is or has been 

 seriously abundant in Vermont, Connecticut, Massachusetts, Ohio, 

 and the State of "Washington.* For fifteen years it has been present 

 in Nevada, where it has proven destructive to our most valuable shade 

 trees, the Cork Elm, Ulmus campestris and the American Elm, Ulmus 

 Americana. It is still abundant in this vicinity and is spreading rap- 

 idly. 



It belongs to the order Hemiptera, family Coccidae, and is known 

 to entomologists as Gossyparia spuria, Modeer. In its earlier stages 

 it is a minute, six-legged insect which can crawl actively over the bark . 

 and leaves, but which spends most of its time in one spot on bark or 

 leaf with its slender beak inserted in the tissues of the plant on whose 

 sap it feeds. 



In summer the surest sign of the presence of this insect is a pre- 

 mature yellowing of the leaves on the lower branches of infested trees. 

 Late in the summer, seriously infested branches turn prematurely 

 yellow or brown to such an extent that one can pick out at a glance 

 the elms on which the scale insects are present in large numbers. 

 Other branches still more seriously infested, die in mid-summer. 

 The wilted leaves on such branches bleach to a dull grey-green or dull 

 brown wholly unlike the normal clear brown of elm leaves in the 



•"Since Its advent In Spokane it has multiplied so rapidly as now to be a serious menace 

 to the propagation of shade trees in that City."— Melander, Washington Experiment Station. 

 Bulletin 74. 



