P&PDL Picture of the Week for
February 2, 2004

Dead or Alive?

Karen Rane, Plant Disease Diagnostician, Department of Botany and Plant Pathology, Purdue University

Two large conifers stand side by side – the tree on the left appears green and healthy, while the tree on the right has lost all its foliage, and looks dead. What happened? Should the leafless tree be removed? This photograph illustrates one of the fundamental principles of plant disease diagnosis – know what is normal! The picture was taken in late February, and the trees are two different conifer species. The normal evergreen is a Norway spruce, and the “dead” tree is a European larch. Larches are deciduous conifers, and like deciduous broadleaf trees, larches lose all their foliage in the fall and produce new needles each spring. The bare branches are normal for this species at this time of year. Knowing what a plant normally looks like throughout the year will help you to identify when abnormal symptoms develop. In this case, the tree will look just fine once spring arrives!

Click image to enlarge

Norway Spruce and
European Larch


Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service