FREE ISA Pest and Disease Diagnosis Questions and Answers

Question 1

An arborist is examining a maple tree showing dieback and chlorosis.
While inspecting the trunk, the arborist finds several small, dark, mushroom-like structures growing from the bark.
How would these structures be classified in a diagnosis?

Accepted Answer

A sign of a fungal pathogen

Answer

A symptom of root rot

Answer

An abiotic disorder indicator

Answer

A physiological response to stress

Question 2

A row of linden trees planted along a newly installed sidewalk all exhibit leaf scorch and branch dieback on the side facing the street. The damage is uniform across all trees in the row. Damage on the opposite side of the trees is minimal. What is the most likely cause?

Accepted Answer

Abiotic stress from reflected heat and/or de-icing salt

Answer

An insect borer infestation

Answer

A bacterial leaf spot disease

Answer

A systemic fungal wilt

Question 3

For a biotic disease to develop in a tree, three components must be present, often referred to as the "disease triangle." Which of the following correctly lists these three components?

Accepted Answer

A susceptible host, a virulent pathogen, and a conducive environment

Answer

An insect vector, a weakened host, and high humidity

Answer

A nutrient deficiency, a virulent pathogen, and compacted soil

Answer

A susceptible host, a mechanical injury, and a secondary pest

Question 4

Upon inspecting a birch tree, an arborist notices several D-shaped exit holes in the bark of the trunk and larger branches. This specific sign is a key diagnostic feature for which type of insect?

Accepted Answer

Flatheaded borers

Answer

Aphids

Answer

Scale insects

Answer

Tent caterpillars

Question 5

The fungal pathogen responsible for Dutch elm disease (*Ophiostoma* spp.) is primarily spread over long distances and introduced to new, healthy trees by which vector?

Accepted Answer

Native and European elm bark beetles

Answer

Root-to-root grafts with neighboring infected trees

Answer

Splashing rain carrying spores to fresh wounds

Answer

Wind carrying spores from dead elms

Question 6

An arborist is assessing a large white oak in mid-summer. The client reports that leaves are browning and dropping prematurely. The arborist observes that the damage is most severe on the lower and inner branches, and the browning on the leaves is irregular and concentrated along the veins. What is the most likely diagnosis?

Accepted Answer

Anthracnose

Answer

Oak wilt

Answer

Bacterial leaf scorch

Answer

Iron chlorosis