Robonen E.V., Chernobrovkina N.P., Chernyshenko O.V., Zaitseva M.I. SOURCES OF FOLIAGE FOR ARGININE IMMUNOSTIMULANT MANUFACTURING. Potential sources of L-arginine-rich needles, their availability and amounts are considered. Experiments for drawing up the fertilizer application and plant material harvesting plan were carried out in a young Scots pine stand naturally regenerated in a powerline corridor. We prove that late summer application of fertilizers is acceptable for enhancing L-arginine storage in Scots pine needles.