Mod 2 - Triage diagnosis

Question 1

Whats the first thing to know before conducting a triage diagnosis?

Answer 1

What a healthy plant looks like

Question 2

Describe the 4 main types of symptoms that can be caused by a plant pathogen

Answer 2

• Necrotic = tissue death e.g. rots, blights
• Hyperplastic = abnormal growth of tissues e.g. galls, witches brooms
• Hypoplastic = underdevelopment or impairment of function e.g. vasculatr wilts
• Colour change = e.g. chlorosis, mosaic, mottle

Question 3

Describe symptoms of chewing invertbrates

Answer 3

• missing sections of leaves (notching or shothole) or complete defoliation
• chewing patterns
• leaf mining - feeding between layers
• boring and tunneling through woody parts

Question 4

Describe symptoms of piercing invertebrates

Answer 4

• discolouration and deformation of leaves/fruits
• spots/leisions
• scarring
• bronzing/silvering on plant tissue
• whole plant or shoot stunted growth

Question 5

What are some other (non-specific) invertebrates symptoms?

Answer 5

egg laying causing:
- galls
- root damage
- blemishes
- sap leaking

Question 6

List the 4 potential causes of abiotic problems w/ examples.

Answer 6

• Moisture extremes = water stress
• Nutrient or pH imbalance = soil pH too acidic, nitrogen toxicity
• Chemical damage = herbicide burn
• Physical damage = hail damage

Question 7

How would you distinguish between biotic and abiotic symptoms?

Answer 7

• Watch the symptom overtime and on several occasions to watch how it progresses.
• Biotic symptom = progressive and scattered damage to neighbouring plants
• Abiotic symtpom = restircted damage that doesn’t tend to move quickly.

Question 8

Sign vs symptom

Answer 8

• Sign = observable part or remnant of a causal agent
• Symptom = a plan’ts response to a pest or disease - abnormal physiology, development or behaviour.

Question 9

List some signs an invertebrate is present

Answer 9

• Eggs
• pupae
• whole insects
• carcases e.g. aphid mummies
• frass
• cocoons
• sooty mould

Question 10

List some signs of disease

Answer 10

• mildew
• mould
• spores/fruiting bodies
• Ooze or stringing (bacteria)
• Smut

Question 11

What are the steps in a triage diagnosis?

Answer 11

1. List of known pests - put together a list of pests that impact the host of interest.
2. Symptoms and signs - ID and describe the symptoms/signs you see + their progression, plant part etc.
3. Further questions - ask Qs about how the plant/crop is being treated, how the disease has progressed, enviro conditions etc.

Consider abiotic stressors along each step

Question 12

What is triage diagnosis?

Answer 12

The preliminary assessment of the possible cause of a suspected pest problem