Source webinar: Cut Flower Symposium, segment 08 of 08, July 23, 2026
Speaker: Bikash Ghimire, Ornamental Pathologist, Department of Plant Pathology, University of Georgia
Duration: 28:31
CEU Categories: [PENDING]
Questions: 15 (5 recall, 6 application, 4 analysis)
Scope Notes
Every correct answer is option a. Shuffle the options in Moodle before deploying. Keeping them in a fixed position makes the review pass much faster and is easy to forget to undo.
Three areas of the recording are excluded from assessment, and none of the fifteen questions touches them.
- The mancozeb classification. At 20:35 and again at 27:58 the speaker recommends “copper-based fungicides like mancozeb.” Mancozeb is an EBDC, not a copper. No question, answer, or distractor rests on that pairing, including the bacterial leaf spot and Pectobacterium material around it. His management advice for bacterial disease is assessed only where it does not depend on the product class.
- Block 85, an unresolved word inside the sporangia explanation. Question 5 is built from the zoospore mechanism on both sides of it and does not quote the flagged span.
- Block 182, the second downy mildew host after sunflower. No question names a downy mildew host. Sunflower alone would make a defensible item, but a student watching the segment hears an unintelligible second name in the same breath, and an item that ignores it invites a challenge.
Distractors are sourced, not invented. Each wrong answer is either something the speaker said about a different disease, product, or condition, or a plainly wrong value inside a range he gave. Block numbers for the distractors appear beside the answer trace.
Question 1
Timestamp Reference: 1:19 – 1:41
Difficulty: Recall
According to the speaker, which set of conditions describes high tunnel production?
a) Reduced airflow, high humidity, and high temperature stress
b) Drought, storm, wind, and temperature extremes
c) A combination of field soil and soilless mix with organic amendments
d) Cooler temperatures with a shortened growing season
Correct Answer: a
Explanation: He lists reduced airflow, high humidity, and high temperature stress as the tunnel’s costs, set against better irrigation control, extended seasons, and longer plants with thicker stems.
Source in transcript: blocks 23 to 26 (1:19 to 1:41). Distractor b is his open field list at block 19 (1:00); c is the raised bed description at block 36 (2:29); d inverts the extended season point at block 25.
Question 2
Timestamp Reference: 3:01 – 3:24
Difficulty: Recall
Why does the speaker say a biological fungicide has to go out before the disease appears?
a) It has no curative activity, unlike some chemical fungicides
b) It degrades in high humidity once symptoms are present
c) It is only labeled for use before transplanting
d) It requires a soil temperature that occurs early in the season
Correct Answer: a
Explanation: He states that biological products can only be applied preventatively because they have no curative activity, which some chemical fungicides do have.
Source in transcript: block 42 (3:14). Distractors b, c, and d are not claims he makes about biologicals anywhere in the segment; c borrows the pre-plant timing he gives for soil treatments at blocks 100 to 101 (8:44).
Question 3
Timestamp Reference: 4:21 – 4:53
Difficulty: Analysis
The speaker says root and stem pathogens tend to have a wide host range while foliar pathogens tend to be host specific. What reason does he give for the difference?
a) Root and stem pathogens live in the soil, so they encounter and infect many plant types
b) Root and stem pathogens reproduce faster and mutate more often
c) Foliar pathogens are killed by ultraviolet light on most hosts
d) Foliar pathogens depend on insect vectors that visit only one plant family
Correct Answer: a
Explanation: He ties the wide host range directly to soil residence: because they are in the soil they can infect different plant types. Foliar pathogens he describes as specific to a plant type or even a cultivar, without giving a mechanism.
Source in transcript: blocks 53 to 57 (4:21 to 4:53). Distractor d borrows the insect transmission he describes for viruses at block 226 (21:28), which is a different disease group.
Question 4
Timestamp Reference: 5:08 – 6:15
Difficulty: Application
A grower brings in plugs from an outside supplier and sees no symptoms on arrival. Based on the speaker’s list of inoculum sources, what should the grower expect?
a) Symptoms may appear later, because incoming plants are often asymptomatic at first
b) The plugs are safe, because a pathogen would be visible within the first week
c) The risk is limited to the seed lot rather than the plants themselves
d) Symptoms will only develop if the plugs are potted into field soil
Correct Answer: a
Explanation: He names infected plants brought in from outside as a source and adds that the plant is often asymptomatic at the beginning, producing symptoms over time and becoming a problem later.
Source in transcript: blocks 64 to 66 (5:28 to 5:46). Distractor c narrows his list to the infested seed route at block 63 (5:15), which is only one of the six he gives.
Question 5
Timestamp Reference: 7:26 – 8:10
Difficulty: Analysis
Why does the speaker treat overwatering as the leading predictor of root and crown rot?
a) The spores are motile and need free water to swim to healthy roots
b) Saturated soil raises the pH into the range these pathogens prefer
c) Excess water leaches the nutrients that let a plant resist infection
d) Standing water carries sclerotia up from lower soil layers
Correct Answer: a
Explanation: He shows a pathogen producing sporangia containing zoospores, describes those spores as motile, and says they need water: given free water they swim to a healthy root system and cause the problem. That is why he calls the group water molds.
Source in transcript: blocks 85 to 91 (7:26 to 8:02). Distractor d borrows sclerotia, which he introduces for Sclerotinia and southern blight at blocks 110 and 131, not for water molds.
Question 6
Timestamp Reference: 8:02 – 8:38
Difficulty: Application
A grower pulls a wilting plant and wants to confirm root rot in the field without sending a sample. Which pair of observations does the speaker give?
a) A soft root system that sloughs off, plus a bad odor
b) A tan stem lesion with white fuzzy growth above it
c) Angular spots in the leaf veins with a yellow halo
d) White radiating hyphae at the crown with mustard-like structures
Correct Answer: a
Explanation: He describes the root system as soft and sloughing off and adds that a bad odor lets you identify the pathogen and the disease behind the scene.
Source in transcript: blocks 92 to 93 (8:02 to 8:10). Distractor b is his white mold description at blocks 108 to 109 (9:39); c is bacterial leaf spot at blocks 211 to 213 (20:06); d is southern blight at blocks 130 to 131 (11:30).
Question 7
Timestamp Reference: 9:06 – 11:02
Difficulty: Recall
How long does the speaker say Sclerotinia sclerotia can survive in soil, citing published work?
a) Five years or even more
b) One full growing season
c) Two to three years
d) Up to twenty years
Correct Answer: a
Explanation: He says papers and literature have reported survival of five years or even more in the soil, which is why crop rotation alone may not clear the problem.
Source in transcript: block 118 (10:43). Distractors are wrong values inside and outside the figure he gives; he separately mentions “five years, even 10 years” for soilborne survival structures generally at blocks 34 to 35 (2:17), so d overshoots even that.
Question 8
Timestamp Reference: 9:21 – 11:14
Difficulty: Analysis
White mold and southern blight share most of their environmental requirements. According to the speaker, what separates them?
a) Temperature: white mold favors cool conditions, southern blight favors warm
b) Soil type: white mold needs sand, southern blight needs clay
c) Host range: white mold is host specific, southern blight is not
d) Water: white mold needs standing water, southern blight needs dry soil
Correct Answer: a
Explanation: He introduces southern blight by comparing it to white mold, saying it favors warm rather than cool conditions while the other environmental conditions are pretty much similar, with both wanting humidity and moisture.
Source in transcript: blocks 106 and 124 to 126 (9:21 and 11:11). Distractor c borrows the host specificity he assigns to foliar pathogens at block 57 (4:43).
Question 9
Timestamp Reference: 11:47 – 12:19
Difficulty: Application
Southern blight has appeared in a bed. What physical step does the speaker describe after removing the infected plant?
a) Dig about eight centimeters deep, flip the soil, and bury the sclerotia
b) Solarize the bed under clear plastic for six weeks
c) Replace the top layer with fresh soilless mix
d) Drench the area with a systemic fungicide at double rate
Correct Answer: a
Explanation: He says to dig there, remove the diseased plant, then dig soil about eight centimeters deep and flip it so the sclerotia are buried deep enough that they cannot come out. The pathogen remains but stops being a problem.
Source in transcript: blocks 132 to 135 (11:47 to 12:08). Distractor b borrows soil solarization, which he gives for water molds at block 101 (8:54) and not here; d contradicts his minimum dose and rate point at block 49 (4:02).
Question 10
Timestamp Reference: 12:19 – 12:35
Difficulty: Recall
What does the speaker say fungicides can and cannot do for a plant already showing southern blight?
a) They protect uninfected plants and new growth but do not cure the diseased plant
b) They cure the diseased plant if applied within 48 hours
c) They have no effect on this pathogen at any timing
d) They work only as a soil drench and never as a foliar spray
Correct Answer: a
Explanation: He says some fungicides are effective but do not help the diseased plant, only the non-infected plant or the new growth, and corrects himself to say plainly that it does not cure and has to be applied preventatively.
Source in transcript: blocks 137 to 141 (12:19 to 12:36). Distractor c overstates his point; he says the materials are effective, just not curative.
Question 11
Timestamp Reference: 13:39 – 15:16
Difficulty: Application
A grower loses stems to gray mold in the cooler rather than in the field. How does the speaker frame that?
a) Botrytis is a problem in the standing plant and again after harvest when storage is not right
b) Post-harvest gray mold is a different pathogen from the field form
c) Gray mold cannot establish once a stem is cut
d) Post-harvest losses come from bacterial soft rot rather than Botrytis
Correct Answer: a
Explanation: He says Botrytis can be in the standing plant and also in the harvested flower, and that it becomes a problem when the flowers do not get proper storage, calling it a source of real economic loss.
Source in transcript: blocks 152 to 153 and 164 (13:39 to 15:16). Distractor d borrows bacterial disease from the closing question at 27:54, which concerns standing plants.
Question 12
Timestamp Reference: 14:28 – 15:49
Difficulty: Recall
Above what humidity does the speaker say Botrytis spores become windblown?
a) 85 percent
b) 50 percent
c) 65 percent
d) 95 percent
Correct Answer: a
Explanation: He gives high humidity above 85 percent as the point at which the oval, clustered spores go windblown, and adds that they can also be splashed by overhead irrigation or rain.
Source in transcript: blocks 159 to 161 (14:28 to 14:41). Distractors are wrong values around the single figure he states.
Question 13
Timestamp Reference: 16:14 – 16:31
Difficulty: Analysis
A grower sees the same white powdery growth on sunflower and on zinnia. What does the speaker say about treating them as one problem?
a) The signs look alike, but the pathogen species differ by host because powdery mildews are host specific
b) They are the same pathogen, so one spray program covers both
c) The sunflower form is a downy mildew and the zinnia form is a powdery mildew
d) Only the zinnia form produces spores, so only it spreads
Correct Answer: a
Explanation: He says the same powdery mass appears on the leaf surface but there may be a different species of pathogen for each host type, and states outright that the pathogen in sunflower might not be the same as the one in zinnia even though symptoms and signs look very similar.
Source in transcript: blocks 171 to 174 (15:54 to 16:23). Distractor c mixes in downy mildew, which he treats as a separate disease starting at block 179 (16:54).
Question 14
Timestamp Reference: 19:07 – 19:52
Difficulty: Application
A grower has recurring Cercospora leaf spot in zinnia and irrigates overhead. Which two changes does the speaker recommend?
a) Move off overhead irrigation to manual watering, and remove debris and dead stems from the field
b) Increase the nitrogen rate and shorten the harvest interval
c) Switch to a closer plant spacing and irrigate more often
d) Leave the residue in place as a mulch and treat with a systemic at bud break
Correct Answer: a
Explanation: He says spores are water splashed, so a grower on overhead irrigation might want to cut that off and go to manual irrigation, and separately that debris and dead stems and leaves have to come out of the field so they are not a source of inoculum.
Source in transcript: blocks 200 to 205 (19:07 to 19:43). Distractor c inverts his spacing and air circulation point at blocks 167 to 169 (15:30).
Question 15
Timestamp Reference: 22:23 – 23:24
Difficulty: Application
A grower suspects a virus in zinnia and wants a same-day answer on site. What does the speaker describe, and how is the result read?
a) An Agdia ImmunoStrip, read in about five minutes, with two lines positive and one line negative
b) A soil drench bioassay read after 24 hours in a warm room
c) A hand lens examination of the underside pustules for spore colour
d) A sample mailed to the diagnostic lab, with results in about five days
Correct Answer: a
Explanation: He describes macerating the infected leaf, putting it in the buffer bag with the strip, and reading the result in as little as five minutes like a pregnancy test kit: two lines positive, one line negative. His example zinnia reads TSWV positive and INSV negative.
Source in transcript: blocks 233 to 239 (22:23 to 22:58). Distractor c borrows the rust pustule examination at block 187 (17:36); the strips cost six to eight dollars each per block 242 (23:11).
Answer Key
| Q | Answer | Difficulty | Topic |
|---|---|---|---|
| 1 | a | Recall | High tunnel conditions |
| 2 | a | Recall | Biologicals are preventive only |
| 3 | a | Analysis | Soilborne host range |
| 4 | a | Application | Asymptomatic incoming plants |
| 5 | a | Analysis | Zoospores and free water |
| 6 | a | Application | Field diagnosis of root rot |
| 7 | a | Recall | Sclerotia survival |
| 8 | a | Analysis | White mold against southern blight |
| 9 | a | Application | Burying sclerotia |
| 10 | a | Recall | Preventive fungicide action |
| 11 | a | Application | Botrytis after harvest |
| 12 | a | Recall | 85 percent humidity |
| 13 | a | Analysis | Powdery mildew host specificity |
| 14 | a | Application | Leaf spot and overhead irrigation |
| 15 | a | Application | ImmunoStrip reading |
Distribution: 5 recall, 6 application, 4 analysis. The analysis share runs slightly above the 20 percent target because the segment repeatedly explains why a practice works rather than only what to do, and questions 3, 5, 8, and 13 assess exactly that reasoning.
Shuffle before deploying. Every correct answer above is option a.
Processed for UGA Center for Urban Agriculture / Cut Flower Symposium Archives
Sources: Corrected SRT (Stage 1), GTBOP_Transcript_2026-07-23_GhimireDiseaseManagement.srt (315 blocks); Archive Package (Stage 2), GTBOP_Archive_Summary_2026-07-23_GhimireDiseaseManagement.md