PINACE^ 81 



Several insect pests attack the silver firs, species of Chermes 

 {Dreyfusia) being the most injurious. Chermes picea, var. bouveri, 

 attacks the buds of A. nobilis, A. ainahilis, A. grandis, A. magni- 

 ficn, A. Fraseri, and other species, whilst Chermes nusslinii injures 

 the young shoots of A . pectinata, A . Nordmcmniana, etc. The first- 

 named, by puncturing the buds, occasions derangement of tissue. 

 The buds are unable to develop, although the branches live for 

 several years. Apparently a concentration of food material 

 occurs about the points of the shoots causing large gouty swellings. 

 All growth buds are eventually suppressed and the trees die. 

 C. 7iusslinii injures the young woody tissue of A. pectinata and 

 A. Nordmanniana, and badly affected young plants rarely recover. 

 Research work on these insects is being conducted by Mr. R. N. 

 Chrystal for the Scientific and Industrial Research Committee, 

 and much new information on these important forest pests is being 

 brought to light. The vital time when the attention of cultivators, 

 should be directed to these pests is when the plants are in the 

 nursery. Plants are then easy to handle, and by keeping them 

 thoroughly clean at this period much future trouble and loss may 

 be avoided. Slightly affected trees, either in the nursery or garden, 

 should be sprayed several times at intervals of eight to ten days 

 with a paraffin wash. Badly infested stock should be burnt. 



Key to Abies. 



Leaves radially arranged on the branchlets ; apex of the leaves 



not notched. 

 Leaves rigid, less than | in. long, thick, obtuse at apex ; 



resin canals median. — A. Pinsapo. 

 Leaves flattened, about 1 in. long, ending in a sharp horny 



point ; resin canals marginal. — A. cephalonica. 

 Leaves flattened, up to about 1 in. long, ending in a sharp 



horny point, ultimately strongly refiexed on the main 



shoots. — A. recurvata. 



Leaves on lateral branchlets pectinate, with a distinct parting 

 between the two lateral sets : — 



Resin canals marginal : — 

 Buds I in. or more long. 

 Leaves 2 in. or more long, rigid ending in a spiny point ; 

 shoots glabrous ; buds spindle-shaped, -|-| in. long, with 

 light brown non-resinous scales.— .4. hracteata. 



Buds less than | in long. 



Leaves all in one plane, those in the upper rank about half as 

 long as those below ; up to 2 in. long, upper surface 

 without stomata ; shoots mmutely hairy ; buds small, 

 resinous. — A. grandis. 



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