Finished Plant Diseases!

Last week my Plant Diseases course at Merritt College in Oakland, California came to an end. Our professor, Dr. Ann Northrup, did a fantastic job teaching the course. We learned about plant pathogens from five kingdoms or phylum – plant, animal, fungus, bacteria, and protists (as well as viruses). We focused on fungi and bacteria, since they are the most prevalent. We learned about the pathogens we experience in the San Francisco Bay Area (water molds are big). I was fascinated to learn about:

• Viruses (bits of genetic code encased in protein), which, when inserted into a plant cell, change its DNA to create a habitat for a vector (such as the oak apple gall that provides housing and food for the Oak Apple Gall Wasp).

Oak apple galls near Clear Lake, California.
Genetic engineering by the Oak Apple Gall Wasp

• The relationships between plants and pathogens (narrow and wide host ranges).
• The native plant-pathogen arms race where each tries for supremacy and adapts in response.
• The dangers of exotic pathogens that can wreak havoc on native plants that have not been in that arms race.
• The built-in mechanisms that plants use to fend off or work with its pathogens. Hint: caffeine and nicotine are poisons that coffee and tobacco plants use as defences against pathogens.
• The merits (and fears) of genetic engineering for ensuring food production as the world’s population soars.
• How well fungi and bacteria will thrive as the planet warms, and the threat to the food supply that will result.

I am sorry to see the class come to an end, but look forward to visiting the Sick Plant Clinic at U.C. Berkeley and continuing to learn more about Bay Area plant diseases and how to manage (or live with) them. With this class, I’ll have met the requirements for the basic Landscape Horticulture certificate at Merritt College. From my point of view though, I’ve just scratched the surface of all there is to learn!