Thanks for your comments on the Fast Plants. Let me add this information:
Plants have been contracting the same disease for at least two and half
years. Each semester we use fresh seeds. In one semester the seeds come
from Carolina Biological Supply, the distributor for Fast Plants in the U.S.
We get both basic wild type and rosette strains. In the other semester, we
get basic wild type and an atrazine-resistant strain directly from the
genetics labs in Wisconsin. All are affected by the disease.
The disease has appeared as early as the cotyledon stage and seems to be
very contagious. All the plants are eventually infected. Symptoms are
somewhat variable from plant to plant. In general, the course of the
disease is this:
1) The leaves develop spots - dark punctate lesions - that are sometimes
more apparent on the upper surface of the leaf.
2) The spots expand, eventually mottling the leaf with grayish beige
areas. These are very obvious. The areas that have been cleared of
chlorophyll are also desiccated.
3) The outer edges of the leaf appear to die first; sometimes the
central vein is still green while the rest of the leaf is necrotic.
4) Eventually the entire leaf becomes dry, brittle and grayish beige.
Thanks for any additional comments,
Dr. Sandra J. Newell
Department of Biology
Indiana University of Pennsylvania
975 Oakland Ave.
Indiana, PA 15705
email: sjnewell at grove.iup.edu