EFFECT OF CONTEMPORARY INFESTATION BY THE SPRUCE APHID (ELATOBIUM-ABIETINUM) ON ROOT-GROWTH IN SITKA SPRUCE TRANSPLANTS

The short-term relative effects on root growth of aphids living on the needle leaves of spruce transplants were examined experimentally. Ult imately, aphids cause the loss of foliage and so defoliation was simul ated in two of the treatments. Aphid populations at a density frequent ly reached in forest conditions, caused no relative inhibition in root growth over a 62-day period. Aphids were expected to have a longer te rm impact, however, since artificial defoliation had significant effec ts on root development.