Inoculation of Populus tremuloides with Pollaccia americana

Abstract

Disease resistance may represent the best approach for controlling shoot blight, caused by Pollaccia americana Ondrej, in aspen (Populus tremuloides Michx.) plantations. Experiments were conducted to develop methods for screening for resistance under greenhouse conditions. Chickpea agar supported abundant inoculum production. An inoculum concentration of 5 × 10⁴ spores/mL and a seedling age of 5-9 weeks were appropriate for evaluating infection. Infection severity was not correlated with tree height or leaf number. Differences in infection among clones varied with fungal isolate. The number of isolates and replicates needed to detect resistance differences among clones was calculated using estimated values of experimental error and clone × isolate interactions.

Keywords:

• aspen shoot blight
• Pollaccia americana