88 PROTECTION OF PLANTS. 1917-18 



Spruce Gall Aphis {Chermes abietis Choi.) — Abundant locall>- on white and 

 Norway spruces, producing pineapple-like galls at base of terminal shoots. 

 Each gall, li inch long, contains about 50 cells each holding from 8 to 12 nymphs. 

 The life-cycle is briefly as follows: — 



"Galls open about mid-August and fully grown pupae emerge and molt with- 

 in a few hours becoming the winged form which deposits a cluster of 40 to 50 

 yellow eggs on a spruce needle. The eggs are extruded from the abdomen but the 

 parent chermes remains over them until dislodged after her death by wind or 

 rain. The winged form often oviposits near the gall from which it emerges. A 

 different species of host plant is never sought by this Chermes. In about two 

 weeks the young "stem-mothers" hatch from these eggs and seek a protecting 

 crevice is the surface of the spruce bud where they can spend the winter. These 

 wingless forms develop in the spring and become full grown about the last of 

 May when they lay a cluster of 140 or more eggs. From these eggs hatch the young 

 that inhabit the gall and are known as the "gall generation" with which we started 

 the cycle." (Patch). 



Spruce Gall Aphid {Chermes similis GUI.) — (Consult Bui. 173, Maine Kgv. 

 Exp. Stn.). 



Abundant locally on black, red, white and Norway spruces, producing loose 

 terminal galls and scraggly deformed twigs. The galls open about 1st July and the 

 winged flocculent migrants oviposit on spruce. 



Control. 



Spray in early spring while trees are dt^rmant with whale oil soap (1 lb. to 2 

 gal. water). Black Leaf 40 (1 to 800) added to soap (1 Ib^ to 4 gal. water). 



Pine Bark Aphid. {Chermes pinicorticis Fitch). — A common enemy of culti- 

 vated pines, appearing as flocculent white masses upon the green bark of the more 

 tender parts. 



Control: Spray in late April or May with fish oil soap or kerosene emulsion. 



