Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Effect of tree age on Diplodia pinea infection of Pinus radiata.

Abstract

Shoot dieback in P. radiata, caused by D. pinea infection, decreases in severity after trees reach 7-8 yr. When cuttings from ortets aged 3, 6, 9 and 15 yr were inoculated with D. pinea under 2 different conditions giving a high and a medium level of infection, however, all age classes proved equally susceptible. The reduction in infections is apparently not due to a stable change occurring in the apical meristem. A nutritional effect due to increased tree size and complexity, or simple disease escape due to changing environment in relation to tree height is a more likely explanation.<new para>ADDITIONAL ABSTRACT:<new para>Shoot dieback of P. radiata caused by D. pinea decreases in severity after trees reach 7-8 years old [cf. FA 38, 1445]. When cuttings from ortets aged 3, 6, 9 and 15 years were inoculated with D. pinea under two different conditions giving high or medium rates of infection, all age-classes were equally susceptible. There is little prospect of using cuttings from older trees to control dieback. Reasons for reduction in dieback in plantations are discussed.