EFFECTS OF NITROGEN-FERTILIZATION ON MONOTERPENES OF JACK PINE-SEEDLINGS AND WEIGHT-GAIN OF JACK PINE BUDWORM (LEPIDOPTERA, TORTRICIDAE)

Nine-month old jack pine (Pinus banksiana) seedlings were grown in a g reenhouse under four nitrogen fertilization regimes. Levels of total n itrogen and five monoterpenes in new foliage were measured. Fertilizat ion resulted in four significantly different levels of foliar nitrogen ; means ranged from 1.8-4.5 percent dry weight. Contrary to prediction s of resource availability theory, seedlings grown under the highest f ertilization regime had higher foliar monoterpene levels than seedling s in the other treatments. Newly molted, sixth-instar female jack pine budworm (Choristoneura pinus pinus [Lepidoptera: Tortricidae]) larvae were allowed to feed for four days on new foliage of the seedlings. L arvae that fed on low-nitrogen seedlings gained less weight and proces sed more vegetation than did larvae on high-nitrogen seedlings. Larval weight gain was positively related to foliar nitrogen.