158 EXPERIMENT STATION EECORD. 



■were dug up and examined. One was dead, the other still alive. 

 Under the bark of the living tree were found the grubs of Magdalis 

 aiinicollis, Saperda tridentaia^ and the adults of Hylesinus opaeid'^is 

 were found making burrows preparatory- to depositing their eggs. 



The author believes, however, that insects are not the tirst cause of 

 the disease. Attention is called to the fact that the habit of elm roots 

 is to remain in the superficial layers of the soil, oftentimes mingling 

 with the grass roots. From this fact it is apparent that any condi- 

 tions w-hich tend to impoverish the soil about the trunks of elm trees 

 will gradually bring about a weakened condition of the trees. The 

 trees will then be less able to resist the attacks of various insects and 

 fungi. 



The remedies suggested by the author are such as will help to replace 

 the soil elements which are needed by the trees. A mulch of humus 

 composed of dead leaves or other nutrient materials might supply the 

 needed food and protect the soil from rapid evaporation and sudden 

 changes in temperature. If it should be found that the beetles attack 

 living- and vigorous trees, it is recommended that the bark be coated 

 with a whitewash containing Paris green or arsenate of lead. Dead 

 and dying elm trees should be cut down and burned, in order to pre- 

 A'ent the spread of injurious beetles. 



The imported elm-leaf beetle {GaleruceUa luteola) is reported as 

 occurring in large numbers and injuring English elms. American elms 

 w'ere comparatively free from the attacks of this insect. A brief 

 description is given of the beetle in its various stages, together with 

 notes on its habits and life history. For the attacks of this beetle the 

 author recommends spraying with Paris green or arsenate of lead. 

 The application should be made in the early spring as soon as the leaves 

 unfold, and usually 3 sprayings should be sufficient. The larv?e and 

 pupa3 which accumulate at the base of the tree may be easily destroyed. 

 Among the natural enemies of this beetle the author mentions the 

 praying mantis and Podisus sjylnosus. 



The elm-leaf ^'keX^tomx^v {Canars la ulmlarrosorella) is reported as 

 injurious to the white elm. Larva? kept in breeding cages pupated 

 either about the leaves or in the earth. The adults emerge during the 

 latter part of March and in early April. Spraying with Paris green 

 or arsenate of lead is recommended against this insect. 



The elm-bark beetle {IlyJeshius ojkichIus) was found in all diseased 

 elms. The adults emerged from September 14 until October 15. The 

 form of the burrows of this insect is described. The insect attacks 

 elms only wlien they are badly diseased. 



Insect attacks in 1899, R. S. McDougall {Trans. Highland and 

 Agr. Soc. Scotland, J. ser., 12 {IdOO^iny- 295-307, figs. d).—Cossns lig- 

 n'lperda is reported as injurious to birches and poplars. A brief 

 description of the insect in its various stages is given. The female 



