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Plant Diseases

Plant Diseases. A disease is defined as any type of injurious abnormality A pathogen is any biological agent that causes an injurious abnormality. Plant diseases. There are 4 types of commonly recognized pathogens Virus Bacteria Fungi nematodes. Signs and Symptoms.

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Plant Diseases

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  1. Plant Diseases • A disease is defined as any type of injurious abnormality • A pathogen is any biological agent that causes an injurious abnormality

  2. Plant diseases • There are 4 types of commonly recognized pathogens • Virus • Bacteria • Fungi • nematodes

  3. Signs and Symptoms • Symptom is the plants response to attack by a pathogen • Sign is structures produced by the organism ( spore producing structures, mycelium)

  4. Virus Tobacco Mosaic Virus

  5. TMV

  6. TMV

  7. Virus symptoms • Unthrifty plants • Slow to grow • Mosaic light spots and stripes

  8. Aster Yellows Acts like a virus but is a mycoplasma

  9. Virus indexing • If you are buying cloned plants they will often say Virus Indexed. • That means they are tested and proven to be virus free. • very important when buying raspberry plants or strawberry plants

  10. Bacteria- fire blight

  11. Fire Blight

  12. Bacterial symptoms • Rapid spread, can be spread by wind or insects,humans • Soft rots producing snotty oooz • Can be really smelly

  13. Fungi Botrytis – Grey Mold

  14. Fungus

  15. Fungus • Signs: mycelium, fruiting bodies • Symptoms: necrotic areas, wilt when fungus attacks the roots • Phloem blockage, xylem blockage

  16. Root Knot Nematode Nematodes

  17. Nematodes • Feed on roots and allow secondary infections • Cause small tumors on roots

  18. Damage to plants by fungi bacteria and nematodes can be classified in 3 types • Direct damage by feeding • Toxins injected into the plant • From secondary infections that enter via the physical damage caused by the primary agent

  19. Crop infesting diseases are troublesome because they will continue to reproduce and feed UNTIL • 1. The food is used up • 2. the environment becomes unfavorable • 3. they are destroyed by some predator/ disease

  20. Disease transmission • Water is necessary for fungus infection • Insects • Humans • Infected seed • Infected soil – brought in on shoes or tractor tires

  21. Curing or avoiding plant disease? • Any of the previous factors can be interrupted • Cultural control • Roguing, sanitation, plowing plant refuse under, stirring the soil to expose egg masses, keep plants healthy, avoid smoking, regulate pH, hot water treatment of seed, • Chemical control

  22. What are those letters? • · V Verticillium Wilt Virus • · F Fusarium Wilt Virus • · N Nematodes • · T, TMV, ToMV Tomato Mosaic Virus • · BSK Bacterial Speck • · ST Stemphyllium (Grey Leaf Spot) • · FCR Fusarium Crown Rot

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