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Chapter Seven
Hungry Planet: Stories of Plant Diseases

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C7.1. A variety of fungal contaminants growing from infested seed placed on a nutrient medium.   
C7.2. Barley seed embryo infected by the loose smut fungal pathogen (right) and an uninfected embryo (left) (light micrograph). C7.3. Virus-infected potato plants should be removed ("rogued out") to prevent the spread of the virus to healthy plants. 
C7.4. Onion cull piles are a source of Onion yellow dwarf virus, which is spread by aphid vectors. Cleaning up such waste piles is a form of sanitation.    C7.5. Washing a log truck before it enters a "clean" area to prevent the spread of a Phytophthora species, a soilborne pathogen. 
C7.6. Steam being used to reduce soilborne pathogens in Massachusetts before chemical fumigants became available.    C7.7. Propane flaming of peppermint debris after harvest reduces inoculum of Verticillium species entering the soil.
C7.8 Soil solarization. Soil is treated by covering it with clear plastic sheeting for 4-8 weeks.    


C7.9. Tomatoes staked and growing on plastic mulch to aid drying of plant surfaces and to protect plants from soilborne pathogens that might splash up from soil.  C7.10. Removal of dew on turfgrass by early morning mowing can reduce fungal diseases.  
C7.11. Overhead irrigation of greenhouse-produced tomato transplants. This method of irrigation can potentially contribute to pathogen dispersal and leaf wetness, which favors infection by bacteria and fungi. C7.12. Experimental plots with plants tolerant (left) and susceptible (right) to soybean rust.

Disease cycle of southern corn leaf blight, caused by Bipolaris maydis.