PCA - Plant Pathogens Exam Latest Update 2025-2026 470 Questions and 100% Verified Correct Answers Guaranteed A+
Abiotic factors of plant disease - CORRECT ANSWER: Air pollution, temperature,
nutrients
Advantages and Disadvantages of fumigation - CORRECT ANSWER: Fumigants are
biocides so they have the potential to kill pathogens, but they can also kill beneficials and crops. Have to be applied pre-plant, are expensive, and may not fully control
Agrobacterium sp. - CORRECT ANSWER: Crown gall
Alternaria sp. - CORRECT ANSWER: Tomato black mold
Antagonists - CORRECT ANSWER: an organism that limits or counteracts another
organism
antibiotics - CORRECT ANSWER: compounds that block the growth and reproduction of bacteria
Apothecium - CORRECT ANSWER: cup-shaped ascocarp
Apple scab biology - CORRECT ANSWER: Necrotroph
Apple scab class - CORRECT ANSWER: Ascomycetes
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Apple scab life cycle - CORRECT ANSWER: Sexual stage: ascospores from pseudothecia
Asexual structure: conidia
Resistant survival stage: overwinters in fallen apple leaves
Host range: apple, crabapple
Apple scab management - CORRECT ANSWER: Resistant cultivars, fungicides,
removal/destruction of fallen leaves
Apple scab symptoms and signs - CORRECT ANSWER: Lesions on leaves and flowers,
scabs on apples, defoliation and cracked/deformed fruit
Arceuthobium sp. - CORRECT ANSWER: Dwarf mistletoe
Armillaria sp. - CORRECT ANSWER: Oak root fungus
Ascocarp - CORRECT ANSWER: Fruiting body of an ascomycete
Ascomycetes of importance - CORRECT ANSWER: Erysiphe necator, Taphrina sp.,
Venturia sp., Colletotrichum acutatum, Sclerotinia sp., Monilinia sp.
Ascospore - CORRECT ANSWER: sexual spores of ascomycete fungi that develop
within an ascus
Aster yellows disease reservoirs - CORRECT ANSWER: Weeds
Aster yellows insect vector - CORRECT ANSWER: Leafhoppers
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Bacterial Plant Pathogen Characteristics - CORRECT ANSWER: Prokaryotic, reproduce asexually, enter through wounds or natural openings, ooze is a typical sign
Basidiomycetes of importance - CORRECT ANSWER: Ustilago sp., Puccinia sp.,
Armillaria sp., Sclerotium sp., Rhizoctonia sp.
Basidiospore - CORRECT ANSWER: A sexual fungal spore produced in a basidium,
characteristic of the basidiomycetes
Bean common mosaic potyvirus control - CORRECT ANSWER: Disease-free seed,
resistant genes to one of the pathogens
Bean common mosaic potyvirus disease - CORRECT ANSWER: Bean common mosaic
Bean common mosaic potyvirus host range - CORRECT ANSWER: Dry beans
Bean common mosaic potyvirus symptoms - CORRECT ANSWER: puckering,
blistering, distortion and rolling of leaves, mosaic pattern, stunted plants
Bean common mosaic potyvirus transmission - CORRECT ANSWER: Seed
transmission
Bean common mosaic potyvirus vector - CORRECT ANSWER: Aphids
Beet curly top geminivirus control - CORRECT ANSWER: Monitoring and treatment for beet leafhopper, treatment of leafhopper by growers not recommended
Beet curly top geminivirus disease - CORRECT ANSWER: Curly top disease
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Beet curly top geminivirus host range - CORRECT ANSWER: potatoes, cucurbits,
sugarbeet
Beet curly top geminivirus symptoms - CORRECT ANSWER: Dwarfing, rolling,
yellowing of upper leaves, leaves have yellow margins and become twisted, veins of outer leaflets remain green
Beet curly top geminivirus vector - CORRECT ANSWER: Leafhoppers
Beet necrotic yellow vein furovirus control - CORRECT ANSWER: Plant rhizomania-
resistant cultivars, avoid planting sugarbeets 2 years in a row
Beet necrotic yellow vein furovirus disease - CORRECT ANSWER: Rhizomania of
sugarbeets
Beet necrotic yellow vein furovirus host range - CORRECT ANSWER: Sugarbeet
Beet necrotic yellow vein furovirus symptoms - CORRECT ANSWER: Root stunting,
proliferation of lateral rootlets, distorted vascular tissue, pale yellowing of leaves, leaf wilt
Beet necrotic yellow vein furovirus vector - CORRECT ANSWER: Polymyxa betae
(soilborne fungus)
Biological control for Crown Gall - CORRECT ANSWER: Agrobacterium tumefaciens
Biotic factors of plant disease - CORRECT ANSWER: Living organisms (fungi, bacteria, viruses)
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