Distribution, host preference, and impact of parasitic mistletoes (Loranthaceae) in young eucalypt plantations in New South Wales, AustraliaThis article is one of a collection of papers based on a presentation from the Stem and Shoot Fungal Pathogens and Parasitic Plants: the Values of Biological Diversity session of the XXII International Union of Forestry Research Organization World Congress meeting held in Brisbane, Queensland, Australia, in 2005.

Abstract

Mistletoe is a common sight in mature eucalypt trees in Australia, especially in remnant stands in agricultural and pastoral areas, where they have been associated with debility and death. We surveyed over 450 eucalypt plantations in New South Wales, Australia, for mistletoe, and report for the first time that mistletoe infestation is becoming a problem in young eucalypt plantations. Forty-three plantations were infected, but only 9 of these had levels of mistletoe of 20% or more trees infected; 4 had levels of 38%, 40%, 65%, and 68%. Mistletoe was observed in plantations ranging in age from 3–10 years old. Species of Corymbia ( Corymbia maculata  (Hook.) K.D. Hill & L.A.S. Johnson and Corymbia citriodora subsp. variegata (F. Muell.) K.D. Hill & L.A.S. Johnson) were the most susceptible to mistletoe. The mistletoe species Dendrophthoe vitellina (F. Muell.) Tiegh. was commonly observed in plantations in both lower and upper northeast New South Wales, while Amyema bifurcata (Benth.) Tiegh. was only observed in the upper northeast. We observed a significant impact on growth of mistletoe, affecting tree growth as young as four years old. Simulated analysis indicated that mistletoe infection can reduce stand basal area by 10% and stand volume by 13%. However, the impact of mistletoe on tree growth was variable across space and time.