37 



the insect appears to find most favorable conditions for multiplica- 

 tion, and it is a matter of the writer's personal observation that 

 many of the large nurseries in this State where elms are thus grown 

 are abundantly supplied with the insect. The elm bark louse is now 

 generally distributed throughout Massachusetts, and may be con- 

 sidered a serious pest, since from the insidious nature of its attack 

 it often escapes notice until the infested trees are injured beyond 

 recovery. The presence of the insect is often indicated by an 

 early yellowing of the foliage on the infested branches and the 

 gradual death of the latter from the tip downward toward the 



trunk. 



Remedies. 



The damage from the imported elm bark louse is a long time in 

 appearing and considerable time is required for the tree to recu- 

 perate from the injury. Badly infested trees should be pruned of 

 all dead and dying branches in the fall, the wounds being covered 

 with thick oil paint or gas tar. At the same time the trunk and 

 branches should be scrubbed with strong kerosene emulsion, made 

 by dissolving one-half pound hard soap in two quarts of hot water 

 and stirring into the mixture while hot one gallon of kerosene oil. 

 Dilute the emulsion with three parts of water and scrub the trunks 

 and branches with this mixture, using a stiff brush. The follow- 

 ing spring, top-dress the ground beneath the trees with good stable 

 manure or with nitrate of soda and later, in July, spray the foliage 

 thoroughly with kerosene emulsion, diluted one part to nine of 

 water. The recommendations given above apply to cases where 

 the trees have been seriously injured. Where the insects occur in 

 moderate numbers, both the scrubbing and spraying may be done 

 in July with satisfactory results. Often a thorough spraying at 

 this time will suffice to destroy the greater part of the insects. 



To show how cheaply this work may be done where a large 

 number of trees are to be treated, the following account of the 

 treatment of 3,000 young elms in Manning's nursery at Reading, 

 Mass., may be of interest: In May, 1896, Mr. Manning found 

 that the elm bark louse had multiplied to such an extent as to 

 seriously infest a large part of his stock of elms. At the writer's 

 suggestion, these elms were scrubbed with strong kerosene emul- 

 sion and in July were thoroughly sprayed with the dilute emul- 

 sion. The cost of the work, taken from data kindly furnished 

 by Mr. Manning, was as follows : Labor, $18 ; kerosene and soap, 

 $3 ; a total expense of $21, or 7 mills per tree. As a result of 

 this treatment over ninety per cent of the insects have been de- 

 stroyed ; in fact it would now be difficult to find a more thrifty lot 

 of elms. This shows the comparative inexpensiveness of the 

 remedy and the good results attending its thorough application. 



