16 



MASS. ]:XPKH!.MKNT STAilOX lULLKJlX 



Piceii e.vccLid. No.iWA^- Si-urti:. A l*'ur(i])(;m .s]>('ci('s \t'ry u cll-kiiow ii ;iiui 

 widely grown in America. It niaUes an admirable liedge, preferably in fairly 

 larue dimensions, (i feet tali or o\er. It stands shearinjz- well and makes a 

 iirm thick surface. It piH'fci-s fairly strong-, cool soil. It will grow almost 

 anywhere, but on dr\, warm soil it soon becon;es ragged. This '"UKith-eaten" 

 efFe<-t is increased if the plants are attacked by the spruce gall louse, as in 

 this \ iciiiitv the\' often are.' 



Norway Spruce 

 A tall sturdy hedge of rapid growth 



' Spruce (Jail Louse. This insect C!lu^es small, m'peu, rone-shaped, multiiile-celled 

 galls to ai)i)ear at the base of young shoots in early summer. The t\\\z Ijeyond these 

 galls i.s often killed and almost invariably deformed. In case of heavy infestation the 

 vitality of the tree is lowered and its appearance marred. 



During the wintei- the youns; lice are located in folds of the bark or clustered 

 around the base of Ijuds. cliietly on the terminal growth. Light yellow eggs are de- 

 Ijosited in early spring, soon after new growth starts. They are usually enveloped in 

 a w'.iite woolly mass of waxy filaments wliich makes them cpiite conspicuous. The 

 young lice usually crawl to the l)ase of tender, growing shoots and are soon enclosed 

 in cells (ir chambers of tlie youns forminir galls, (falls are at first green in color Ijut 

 later become darker, and in late .luly or early August tlie cells oiien and the mature, 

 winged lice esca])e. Tliese produce tlie young lice whicli winter over on the twigs. 



In the case of a few small trees, it is i)ossilile to conti'ol tliis jiest by removing the 

 youii;;'. newly-formed yalls. Tliis sliould be done in .lune or early July. Thorough 

 spraying of infested ti'ees in Aiiril. witli a contact insecticide, lias proved successful. 

 This is aimed to destroy tlie younu' li<-e wintering over on tlie twins. Kspecial care 

 should be taken to t liorou;;lily cover the trees, particularly the terminal tuiis. 



Exi)eriments with various oil s]irays liave given excellent control. Oil sjirays may 

 be used at weaker strengths tlian is necessary for ireneral orcliard practice. They 

 should Ije applied on warm, sunny days with temjieratures of 40"^ F. or above, and 

 preferably during the middle of tlie day. Oil sjnay should always be applied while 

 the trees are in dormant condition tiefore new i;rowth starts in tlie spring: otherwise 

 more or less injury may result. 



Tliis account of the spruce gall louse 

 Kntoiiiologist of the Kxi)eriment Station. 



is contributed by Professor A. I. Bourne, 



