Agricultural Plant Pathology

1. PLSS/PSAS 401Dr. Jason BondMr. Chris Vick / Ms. Amelia Vick Agricultural Plant Pathology Labs 403b Disease of Horticultural Crops – Mon 3-5 - Bond 403a Diseases of Field Crops – Mon 1-3 – Dr. Fakhoury 403c Diseases of Turf – Dr. Diesburg 403d Diseases of Trees – Cancelled ** Images and lecture material were not entirely created by J. Bond. Some of this material was created by others.**

2. Why study plant diseases? • Plant pathogens can have a profound negative affect on world’s food, fiber, or timber supplies and severely impacts quality of lives. • Plant disease epidemics can cause loss of life through starvation in areas where the population is near limits based on food supply. • The study of plant pathology can provide incredible insight into microbial ecology, host physiology, epidemiology, and this insight can be directly translated into similar studies involving animal systems.

5. Why study plant pathology? • Securing a stable and healthy food supply

6. Why study plant pathology? • Fundamental research in plant-microbe interactions

7. Importance of Plant Pathology Politics – Irish potato famine in 1845–1852 (800,000 died, 2.0 million emigrated, ¼ population lost). Many came to the U.S., including Kennedy family. Culture – Coffee rust decimates coffee plantations Sri Lanka and India. Switch to tea because of resistance. Hence British are tea drinkers. It is why we had the Boston Tea party instead of the Boston Coffee Party. History – In 1722, Peter the Great’s invasion of Europe was halted by St. Anthony's Fire, now known to be caused by ergot disease of Rye. During WWI, late blight devastated potato production in Germany and likely hastened the end of the war.

8. Importance of Plant Pathology Mythology – Roman gods Robigus and Robigo were worshipped. These corresponded to the different. stages of wheat stem rust disease. The Robigalia festival was designed to appease these “gods” and ensure a disease-free harvest. Religion – many mentions of blast, mildews, etc. in the Bible.

9. Plant Disease? • Any abnormality of a plant, its parts, or its products that reduces their economic or aesthetic quality. • Any alteration of a plant that interferes with its normal structure, function or economic value. • Abnormal plant physiology. • Malfunctioning of host cells and tissues that results from continuous irritation by a pathogenic agent or environmental factor and leads to the development of symptoms.

10. Plant Disease? These definitions have the following in common: • Abnormal – a better term would be “unhealthy” or “malfunctioning”. A crop variety that yields 2X normal would be considered “abnormal”. • Physiology – all diseases affect at least one physiological process and most affect more than one. Ex.: respiration, photosynthesis, absorption, translocation, reproduction, assimilation, storage. Pathology – “the study of suffering”

11. Categories of Disease • Biotic – caused by infections living organisms such as fungi, bacteria, nematodes, viruses, etc. • Abiotic – caused by non-infectious environmental factors such as temperature, herbicides, pollutants, etc.