THE SITKA SPRUCE IN IRELAND. 265 



any class of soil — the advantage of large plants being greater 

 freedom from spring frost damage, and injury from rabbits. 



The seedlings, being exceptionally slow in growth during the 

 first two years, are difficult to handle, and the best results are 

 usually obtained from thin-seeding and leaving the seedlings in the 

 seed-beds for two or occasionally three years, or until they have 

 reached a height of 6 inches. If transplanted into nursery lines 

 then, they will be fit for planting out at any time after the second 

 year from the seed-bed, according to the situation of the land to 

 be planted and the surface vegetation it carries. 



The only serious enemy of the Sitka spruce hitherto observed 

 in Ireland is a species of aphis, apparently identical with the one 

 found on the common spruce, and usually known as Aphis abietina, 

 Walker. In the winter of* 1912-13 Sitka spruce all over Ireland 

 were attacked by this insect, and it looked at one time as if 

 permanent injury might result from the attack. The aphides 

 were first noticed about November scattered over the needles, 

 and during the winter they increased considerably in numbers 

 until the whole of the shoots of many trees were covered 

 with the pest. The effect on the needles was not noticed 

 particularly until the following February or March, when they 

 acquired a sickly mottled appearance and fell off in large 

 numbers, some trees being quite bare before the new growth 

 commenced at the end of April. The effect upon the summer 

 growth varied a good deal, vigorous trees apparently being little 

 the worse, while weakly individuals made little growth, and an 

 occasional one died altogether. Soil and situation, however, had 

 no great influence upon the attack, plants growing in moist and 

 deep loam suffering almost as much as those in poorer soils, 

 although the final effect upon the former was naturally less. By 

 the end of April few traces of aphides could be seen, although 

 the young needles of 19 13 were not entirely free. A great 

 feature of the attack, however, lies in its continuing during the 

 winter and early spring months, with a certain amount of 

 multiplication from November to March. 



fn the present year, 1913-14, few traces of the insect have been 

 seen, and it is evident that no serious injury has been done. To 

 what this immunity is due it is difficult to say. Both winters 

 were equally mild, and until the life-history of the aphis has 

 been thoroughly worked out, its economic importance with 

 regard to this valuable timber tree must remain undecided. 



VOL. XXVIII. PART II. S 



