CPH Plant Diseases and Pathology 3

Question 1

Plant-parasitic nematodes in landscape and nursery settings are best managed by:

Accepted Answer

Using resistant cultivars, soil solarization, and nematicides

Answer

Applying copper fungicides as a preventive soil drench

Answer

Deep tillage alone to bring nematodes to the surface

Answer

Increasing soil pH above 8.0 to create a hostile environment

Question 2

Phytoplasmas, which cause diseases like aster yellows in ornamental plants, are transmitted primarily by:

Accepted Answer

Leafhoppers that acquire phytoplasmas from infected hosts and transmit them

Answer

Fungus gnats feeding on infected root tissue

Answer

Aphids acquiring and inoculating phytoplasma between plants

Answer

Wind-dispersed ascospores during wet spring weather

Question 3

Mosaic, mottling, and distortion of leaves are most characteristic of which class of plant disease?

Accepted Answer

Viral diseases causing systemic symptom patterns

Answer

Fungal diseases causing necrotic leaf spots

Answer

Bacterial diseases causing water-soaked lesions

Answer

Nematode damage causing localized root lesions

Question 4

In plant pathology, the term 'canker' refers to:

Accepted Answer

A localized, dead, sunken or discolored area on a stem, branch, or trunk

Answer

A yellowing of leaf tissue between the veins

Answer

Root swelling caused by nematode feeding

Answer

A powdery or pustular growth on the leaf surface

Question 5

Botrytis blight (gray mold) caused by Botrytis cinerea is most favored by which environmental conditions?

Accepted Answer

Cool temperatures (60–77°F) and high relative humidity above 90%

Answer

Hot, dry conditions with low humidity above 95°F

Answer

Waterlogged soils with poor drainage and anaerobic conditions

Answer

Full sun exposure with strong UV radiation and dry foliage

Question 6

Which cultural practice most effectively reduces the incidence of foliar fungal diseases such as powdery mildew and leaf spots on landscape plants?

Accepted Answer

Using drip or soaker hose irrigation to keep foliage dry

Answer

Applying high-nitrogen fertilizers to promote rapid new growth

Answer

Pruning all plants heavily in midsummer to remove old tissue

Answer

Increasing planting density to create a humid microclimate

Question 7

When scouting for plant diseases in a landscape, the term 'sign' refers to:

Accepted Answer

Physical evidence of the pathogen itself, such as spores, mycelium, or bacterial ooze

Answer

A symptom such as wilting or chlorosis observed in the plant

Answer

A laboratory test result confirming the causal organism

Answer

An environmental factor such as drought stress associated with disease