and Answer 2026 | Ultimate Exam
Preparation Bundle | Grade A+
• Disease. CORRECT ANSWER: Abnormal function caused by a
continuously irritating agent and expressed by noticeable symptoms
• Requirements for disease. CORRECT ANSWER: (1) disease agent; (2)
susceptible plant; (3) favorite environment
• Symptom. CORRECT ANSWER: The visible effect produced in or on
a plant by the presence of pathogen or disease agent
• Sign. CORRECT ANSWER: An indication of a disease from direct
visibility of the pathogen
• Examples of Disease Symptoms. CORRECT ANSWER: Spots,
blights, cankers, diebacks, stunting, chlorosis, galls, root-knot, wilt.
• Disease Agents. CORRECT ANSWER: (1)Living and (2) Non-living
• Living Disease Agent. CORRECT ANSWER: : Fungi, Bacteria,
Viruses, Viroids, Mycoplasmas, Nematodes, Parasitic Higher Plants,
Protozoa
,• Non-living Disease Agent. CORRECT ANSWER: Environmental
factors, Nutrition, Pollution, etc.
• Fungi: small organisms (Kingdom Mycetae). CORRECT 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).
CORRECT 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. CORRECT 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). CORRECT
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. CORRECT ANSWER: i. Exclusion ii.
Eradication iii. Protection iv. Resistance
• Disease Control Practices/Methods. CORRECT 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. CORRECT 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. CORRECT ANSWER: recent
weather, chemicals/fertilizers applied, soil conditions, insect problems,
animal damage disease, nematodes, patterns of the damage
• Collecting/ Packages Mailing Samples Collecting. CORRECT
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