Flashcards
disease
Cards in this deck (16)
- 1Define a disease.Abnormal function caused by a continuously irritating agent and expressed by noticeable symptoms.
- 2Requirements of disease:1. Disease agent
2. susceptible plant.
3. favorable environment - 3Symptoms of diseaseThe visible effect produced in or on a plant by the presence of a pathogen or disease agent
- 4SIGN OF DISEASEAn indication of a disease from direct visibility of the pathoen
- 5Give some examples of disease symptomsSpots, blights, cankers, diebacks, stunting, chlorosis, galls, root-knot, wilt
- 6List 2 types of disease agentsLiving and non living
- 7List living disease agentsFungi,bacteria, viruses, viroids, mycoplasmas, nematodes, parasific higher plants, protozoa
- 8List non living disease agentsEnvironmental factors, nutrition, pollution
- 9List fungi characteristicssmall organisms (Kingdom Mycetae)
8000 species cause plant disease
Cause over 80% of plant disease
Consist of microscopic filaments called hyphae
Reproduce by spores
Identified by spores and reproductive structures
Survive as parasites and saprophytes
Spread by wind/rain/insects - 10List Bacteria characteristicsPrimitive microscopic organisms (kingdom Prokaryotes)
200 species cause plant disease
Microscopic one celled organisms
Reproduce by binary fission
Survive as parsites/saprophyles
Infect plant wounds/natural openings
Spread by wind/rain/insects - 11List virus charateristicsSubmicroscopic structures
500 cause plant disease
submicroscopic organisms
Obligate parasites
Nucleic acid and protein coat
Replicate within the host cell
Infect plants through wounds
Spread by insect/seed/animals - 12NematodesSmall round worms(kingdom-animal)
Need live host to survive
Use stylet to feed on plant cells
Most feed on roots
4 juvenile stages and adult form an over winter egg stage
generation time 30 days (1-5 generations/yr)
Spread by soil transport - 13List 4 disease control principlesExclusion
Eradication
Protection
Resistence - 14List 4 disease control practices/methodsCultural
Chemical
Genetic plant resistant varieties/cultivars
biological - 15Describe field diagnosisObserve plant (ck for foliage for spots, yellowing, marginal burns, growth problems, insect damage
look at stems/crowns discoloration, bacterial ooze
Look for swelling, stunting, no secondary roots - 16List considerationsrecent weather
Chemicals/fertilizers applied
soil conditions
animal damage
nematodes
patterns of damage
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- Flashcards on disease, created by Dee Loucks on 19/05/2015.
- Created by
- Dee Loucks
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