Pest Diagnostics and Disease Management Flashcards
6 cards from real CCA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pest Diagnostics and Disease Management flashcards as text
When submitting a plant disease sample to a diagnostic laboratory, which tissue is most valuable to collect?
Answer: The transition zone between healthy and diseased tissue
The margin between healthy and diseased tissue contains actively advancing pathogens, making it the most diagnostically informative area to sample.
Which laboratory methods are commonly used to detect plant viruses in submitted samples?
Answer: ELISA and PCR
ELISA detects viral coat proteins immunologically while PCR amplifies viral nucleic acids; both are standard diagnostic tools for plant virus identification.
To fulfill Koch's postulates and confirm that a microorganism causes a specific disease, which sequence of steps is required?
Answer: Isolate, identify, inoculate healthy host, reisolate and re-identify the same organism
Koch's postulates require isolating the putative pathogen, inoculating a healthy susceptible host to reproduce symptoms, then reisolating and confirming the same organism from the inoculated plant.
Which environmental condition most consistently favors infection by foliar fungal pathogens?
Answer: Cool to moderate temperatures with extended leaf wetness
Most foliar fungal pathogens require free moisture on leaf surfaces for spore germination and penetration, making cool to moderate temperatures with extended leaf wetness most conducive to infection.
The Baermann funnel technique is used in plant diagnostics to:
Answer: Extract and recover plant-parasitic nematodes from soil or root samples
The Baermann funnel uses gravity and nematode mobility through water to separate nematodes from soil or root tissue for counting and identification.
Whole-plant wilting and yellowing that progresses rapidly through an entire plant most likely indicates infection by which type of pathogen?
Answer: A vascular or systemic pathogen disrupting water transport
Vascular pathogens like Fusarium wilt or bacterial wilt colonize xylem tissue, blocking water movement and causing whole-plant collapse rather than localized symptoms.