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!