OTPS (Alabama) Exam Questions Complete Solutions
New Update (Verified )Graded A+
Disease - Answer-Abnormal function caused by a continuously irritating agent and
expressed by noticeable symptoms
/.Requirements for disease - Answer-(1) disease agent; (2) susceptible plant; (3)
favorite environment
/.Symptom - Answer-The visible effect produced in or on a plant by the presence of
pathogen or disease agent
/.Sign - Answer-An indication of a disease from direct visibility of the pathogen
/.Examples of Disease Symptoms - Answer-Spots, blights, cankers, diebacks, stunting,
chlorosis, galls, root-knot, wilt.
/.Disease Agents - Answer-(1)Living and (2) Non-living
/.Living Disease Agent - Answer-: Fungi, Bacteria, Viruses, Viroids, Mycoplasmas,
Nematodes, Parasitic Higher Plants, Protozoa
/.Non-living Disease Agent - Answer-Environmental factors, Nutrition, Pollution, etc.
/.Fungi: small organisms (Kingdom Mycetae) - Answer-8000 species cause plant
disease ii. Cause over 80% of plant disease iii. Consist of microscopic filaments called
hyphae iv. Reproduce by spores v. Identified by spores and reproductive structures vi.
Survive as parasites and saprophytes vii. Spread by wind/rain/insects
/.Bacteria: primitive microscopic organisms (Kingdom - Prokaryotes) - Answer-i. 200
species cause plant disease ii. Microscopic, one-celled organisms iii. Reproduce by
binary fission iv. Survive as parasites/ saprophytes v. Infect plant wounds/ natural
openings vi. Spread by wind/ insects
/.Viruses: submicroscopic structures - Answer-i. 500 + cause plant disease ii.
Submicroscopic organisms iii. Obligate parasites iv. Nucleic acid and protein coat v.
Replicate within the host cell vi. Infect plants through wounds vii. Spread by
insect/seed/animals
/.Nematodes: small round worms (Kingdom - Animal) - Answer-i. Round worms - plant
parasites are microscopic ii. Need live host to survive iii. Use stylet to feed on plant cells
iv. Most plant nematodes feed on roots v. 4 Juvenile stages and adult form and over-
winter egg stage vi. Generation time 30 days (1-5 generations/yr.) vii. Spread by soil
transport
, /.Disease Control Principles - Answer-i. Exclusion ii. Eradication iii. Protection iv.
Resistance
/.Disease Control Practices/Methods - Answer-i. Cultural: modifications in planting, soil
fertilization, irrigation, soil preparation, etc. ii. Chemical: most are protective sprays;
some chemicals provide eradication iii. Genetic: plant resistant varieties or cultivars iv.
Biological
/.Field Diagnosis Observe Plants carefully - Answer-1. Check foliage for spots,
yellowing, mosaics, marginal burns, growth abnormalities, insect damage 2. Examine
stems and crowns for internal discoloration, external discoloration, fungal structures,
bacterial ooze. 3. Examine roots for discoloration, swelling, stunting, absence of
secondary roots
/.Field Diagnosis Considerations - Answer-recent weather, chemicals/fertilizers applied,
soil conditions, insect problems, animal damage disease, nematodes, patterns of the
damage
/.Collecting/ Packages Mailing Samples Collecting - Answer-1. If spots, collect affected
plant parts 2. If poor growth, collect whole plants 3. Include development stages of the
problem 4. Include damage but not dead plants 5. If large plants, collect 1-3 6. If small
plants, collect several - many 7. Collect and record and include information
/.Collecting/ Packages Mailing Samples Packaging - Answer-1. Gently shake soil from
roots 2. Package plants in dry plastic 3. May need to wrap root ball separately 4.
Packaging loose soil separately 5. Package fruits/crucifiers in newspaper
/.Collecting/ Packages Mailing Samples Mailings - Answer-1. Use a sturdy padded
envelope or box 2. Mail early in week 3. Address properly The Plant Diagnostic Lab 101
Extension Hall Auburn University, AL 36849-5624
/.Laboratory Diagnosis Activities of the Plant Diagnosis Lab - Answer-1. Plant
problem/disease-diagnosis 2. Soil nematode analysis 3. Insect Identification 4.
Weed/plant identification
/.Laboratory Diagnosis Routine Lab Procedures for Plant Sample Problems - Answer-1.
Visual exam 2. Microscopic exam 3. Soil pH 4. Soil soluble salts 5. Culture isolations -
selective media 6. ELSA 7. Nematode analysis 8. Ref. for soil or tissue tests for
minerals 9. Ref. to agronomists, horticulturists, entomologists
/.Laboratory Diagnosis Response to Plant Sample Problems - Answer-1. Identify
problem or disease 2. Give control recommendations 3. To client, usually by regular
mail 4. To count agent, email or phone 5. Service charge invoice included in letter to
client ($10-$15)
