1915 EiNTOMOLOGICAL SOCIETY. 113 



.species which are notoriously destructive to healthy trees prefer weakened bark 

 and wood, and attack it most readily; this is true, particularly, of numbers o£ 

 bark-beetle species; Vigorous trees in full sap are much better able to withstand 

 the attack of some of these destructive borers, and "are of course moTe likely to 

 recover from attacks by defoliating or sucking insects, or from injuries of any 

 sort. 



We have numbers of inquiries each season with regard to dying branches of 

 (,'onifers. When these trees are grown in a close stand they normally lose the 

 lower branches as the dense growth of the crowns above gradually cuts off the 

 .--upply of light. This is certain to occur if the trees are close together, and does 

 not indicate an unhealthy condition. It is possible to retain the beautiful conical 

 .shape 'of the spruce, for example, only when the light has free access to all parts 

 of the tree. Spruces are commonly seriousily affected by gall aphids, and often 

 lo,«e many branches from this caiise. It frequently happens, however, that several 

 branches will die in a season on apparently healthy isolated spruces. The needles 

 turn yellow during midsummer and drop; small portions or entire branches may 

 be affected. There is no insect and apparently no fungus injury, and the trees 

 otlierwise appear to be quite healthy. This trouble appears to be more in evi- 

 dence during dry seasons, and it is probaihly due to lack of sufficient moisture. 



Protection from injuries, and the proper treatment of those received, are of 

 I ho utmost importance. Whenever the bark is broken and left untreated, in- 

 sects and fungi are almost certain to gain entrance. Many of the most serious 

 injuries from decay originate from neglected wounds through which the para- 

 sitic fungus enters. All such wounds should be properly cared for. The broken 

 bi'anches and those to be pruned should be cut off even with the trunk; wounds 

 on the trunk or limhs should be trimmed smooth; and all such cut surfaces .should 

 be disinfected with creosote or bichloride of mercury solution and coated with coal- 

 tar or good paint. Any needed pruning is best done during the dormant period of 

 the trees, while the sap-flow is not sufficient to break through the coating on the 

 wounds. Injury from wind and sleet storms can be lessened by chaining or bolt- 

 ing weaker upright branches together or to the trunk. Eeasonalble care in the 

 prevention of injuries, and in the proper treatment of those which occur, will pre- 

 vent much trouble from insects and fungous rots. Trees which have been badly 

 injured by decay can be saved in many cases by proper surgical treatment. The 

 decayed portions should be entirely removed and the healthy surface thus laid 

 bare, disinfected with creosote or a solution of bichloride of mercury, and then 

 jiainted with coal-tar or good paint. The parts should then be bolted together, 

 if such support is required, and the cavity filled with cement. It is best to have 

 any important work of this kind done by an expert in tree surgery, if such ser- 

 vices are available. 



Clean Culiurc. — All dying and dead hranclies and trees should he removed 

 and burned. Many insects and rot-causing fungi breed in such material and 

 emerge therefrom io attack weakened or even healthy trees or branches If is of fhe 

 utmost importance to cut out or collect all such material promptly and hum it so 

 a.<t to destroy th,e pests which it contains. Make it a rule to remove and burn 

 dyino" wood as soon' as it is detected, and each fall or winter remove all dying and 

 dead trees and parts and, burn them before spring, .so as to destroy the pests which 

 Ib.pv contain. 



