Oleoresin biomass production by trees of Pinus elliottii, which is a source of terpenes for the chemical and pharmaceutical industries, was investigated. Trees were individually analyzed for oleoresin yield using the bark streak method of wounding for stimulation of resin flow. Controls included plain wounding and wounding followed by application of commercial stimulant paste, based on sulfuric acid and synthetic precursors of the phytohormone ethylene. Metal cofactors of terpene synthases and ethylene receptors applied locally as adjuvants of the oleoresin stimulant paste on wounded bark tissue improved resin yields. The use of potassium, copper, and iron did not affect significantly the composition of semiochemical monoterpenes, which are involved with pine - bark beetle interactions, and are important as oleoresin-derived products. Some adjuvants, particularly potassium, were capable of supporting oleoresin yields equivalent to those obtained with current commercial stimulant paste, even with removal of ethylene precursor, the most expensive adjuvant. (C) 2011 Elsevier Ltd. All rights reserved.