Microscopy Primer
Light and Color
Microscope Basics
Special Techniques
Digital Imaging
Confocal Microscopy
Live-Cell Imaging
Microscopy Museum
Virtual Microscopy
Web Resources
License Info
Image Use
Custom Photos
Site Info
Contact Us

The Galleries:

Photo Gallery
Silicon Zoo
Chip Shots
DNA Gallery
Amino Acids
Religion Collection
Cocktail Collection
Screen Savers
Win Wallpaper
Mac Wallpaper
Movie Gallery

Phase Contrast Image Gallery

White Pine Blister Rust

The photomicrograph below illustrates a stained thin section of pine tree stem infected with White Pine Blister Rust, a serious disease of pine trees caused by the fungus Cronartium ribicola. This fungus also is a disease of the Ribes genus (currant and gooseberry bushes), which serves as an alternate host for the fungus.

Although originally from Siberia and Asia, C. ribicola is now found in Europe and North America (both USA and Canada) where it plagues the forest industry and fruit growers alike. It was introduced along with imported trees over the past 200 years and, since 1910, has been devastating native pine ecosystems and, subsequently, the timber industry. In some regions, white pine, the most seriously affected pine species, is no longer considered a viable forest tree species.

This fungus has a complex life cycle that takes up to four years to be completed, requires two hosts, and involves five different types of spores. Both pine trees and the Ribes berry bushes have to be present in the environment for the fungus species to survive. Pine trees can only be infected by spores that develop on the berry bushes and the berry bushes can only be infected by spores that develop on the pine trees. Pycniospores and aeciospores are produced on the branches and stems of pines; urediniospores, teliospores, and basidiospores on currant and gooseberry foliage.

There is no cost-effective treatment for this fungus. Efforts were made, during the early 1900s, to interrupt the life cycle by passing legislation to eradicate currants and gooseberries, which many farms had started growing. Most of this legislation has now been repealed, however, and interest in the cultivation of these berries has increased considerably over the last few years.

Currently, researchers are trying to develop disease resistant pine trees in hopes of reintroducing white pine forests that can survive.


Questions or comments? Send us an email.
© 1998-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Friday, Nov 13, 2015 at 02:19 PM
Access Count Since March 21, 2000: 25019
For more information on microscope manufacturers,
use the buttons below to navigate to their websites: