10. DIAGNOSIS AND PLANT DISORDERS WORKBOOK

Question 1

True or False—Information about a tree’s history and symptoms gained from a client can always be considered accurate.

Answer 1

False

Question 2

If a tree is not well suited for the site in which it has been planted, it may become ______, predisposing it to other problems.

Answer 2

Stressed

Question 3

A common mistake in diagnosis is to carefully examine the aboveground portion of the tree while ignoring the ______.

Answer 3

Roots/soil

Question 4

True or False—If a tree declines or dies within the first year following installation, a likely cause is excess or insufficient water.

Answer 4

True

Question 5

Pollution damage, girdling roots, and mineral deficiencies are examples of ______ disorders.

Answer 5

Abiotic

Question 6

Name five insect pests of trees with chewing mouthparts.

Answer 6

• Caterpillars
• Cutworms
• Sawflies
• Beetles
• Weevils

Question 7

Name five insect pests of trees with piercing-sucking mouthparts.

Answer 7

• Aphids
• Adelgids
• Scales
• Leafhoppers
• Psyllids

Question 8

Insects that carry plant pathogens and introduce them into hosts to result in disease are known as ______.

Answer 8

Vectors

Question 9

True or False—Mites are insects.

Answer 9

False

Question 10

Microscopic worm-like organisms that sometimes feed on or in trees, causing disease, are called ______.

Answer 10

Nematodes

Question 11

Name the four factors required for a tree disease.

Answer 11

• Susceptible host
• Pathogen
• Conducive environment
• Time

Question 12

True or False—Vascular diseases of trees are rarely fatal.

Answer 12

False

Question 13

True or False—Most fungi cause plant disease.

Answer 13

False

Question 14

Fire blight is an example of a disease caused by a(n) ______.

Answer 14

Insect vector/bacterium

Question 15

______ is the chemical inhibition of growth and development of one plant by another.

Answer 15

Allelopathy

Question 16

True or False—Pollution damage is often difficult to diagnose because the symptoms may mimic other problems such as insect injury and mineral deficiencies.

Answer 16

True

Question 17

Curling and cupping of the foliage, and parallel venation, are common symptoms of ______ damage.

Answer 17

Chemical/herbicide

Question 18

What is a condition characterized by a cluster of dwarfed shoots on affected twigs called?

Answer 18

Witch’s broom

Question 19

Twig dieback from periodical cicadas is primarily a result of ______.

Answer 19

Ovipositing (egg-laying)

Question 20

Plant damage associated with a sap-feeding insect pest might appear as ______.

Answer 20

Distorted leaves or shoots

Question 21

Scale damage to plants is the result of ______.

Answer 21

A type of sucking insect causing a loss of vigor

Question 22

Damage caused by nonliving factors tends to be ______.

Answer 22

Uniform and may affect more than one species

Question 23

What is an abnormal enlarged plant structure, often caused by insects or mites?

Usually found on leaves/teigs and roots

Answer 23

Gall

Question 24

What is a carrier of pathogens?

Answer 24

Vector

Question 25

What is localized dead tissue, often sunken and discolored?

Answer 25

Canker

Question 26

What is an abnormal growth of multiple shoots?

Answer 26

Witches Broom

Question 27

What is the term for abnormally reduced growth in plants?

Answer 27

Stunting

Question 28

What may predispose a plant to other problems?

Answer 28

Stress

Question 29

What is the causal agent of disease in plants?

Answer 29

Pathogen

Question 30

What is the progressive death of twigs and branches from the tips back?

Answer 30

Dieback

Question 31

What is the natural chemical inhibition of growth?

Answer 31

Allelopathy

Question 32

Disorders caused by pathogens such as fungi, bacteria, viruses, nematodes, insects etc are considered _______. Also considered infectious!

Answer 32

Living (Biotic) Disorders

Question 33

Approximately what percent of all plant problems result from adverse cultural and abiotic environmental conditions??

Answer 33

70-90%

Question 34

Abiotic (nonliving) agents are ________ and include causes of mechanical injury and environmental conditions such as temperature and moisture extremes

Answer 34

Noninfectious

Question 35

Black roots, a sour smell, and bluish-gray soil may reflect wet and ________ soil conditions.

Answer 35

(Anaerobic) low oxygen

Question 36

The effects if casual agents or factors on the plant. Chlorosis, wilting and leaf scorch.

Answer 36

Symptoms

Question 37

Direct indications of primary or secondary casual agents, or something " left behind" by the casual agent. Fungal fruiting bodies, discarded insect parts etc.

Answer 37

Signs

Question 38

Describes any adverse effects on plant growth, physiology, or metabolism caused by a chemical substance, such as high levels of fertilizers.

Answer 38

Phytotoxicity

Question 39

One of a number of separate plants of certain obligate pathogens or insects on which successive life stages develop. RUST FUNGI/ ADELGIDS. The pathogen requires two hosts to complete life cycle.

Answer 39

Alternate Host

Question 40

Soil that has sufficient oxygen

Answer 40

Aerobic

Question 41

Any disease or disorder, regardless of the casual agent, that rapidly kills flowers, leaves, or young stems that are typically retained.

Answer 41

Blight Examples Verticillium Wilt/Dutch Elm Disease/Fire Blight

Question 42

This pest often induces the development of leaf galls and require higher magnification to see them.

Answer 42

Eriophyid Mites

Question 43

Susceptible host, Pathogen and Conducive environment

Answer 43

Plant Disease Triangle

Question 44

Localized or general death of cells or parts of a living organism.

Answer 44

Necrosis

Question 45

Pathogens or other pests that do not usually attack or infect healthy plants but tend to attack stressed plants.

Answer 45

Opportunistic

Question 46

Exudation of sap, gum, or resin often in response to disease or insect damage.

Answer 46

Gummosis

Question 47

Fungus that appears as a black coating on leaves, branches etc from deposits of sugary excrement from aphids and scale insects.

Answer 47

Sooty Mold

Question 48

Speckled or dotted areas in which chlorophyll is absent on foliage.

Answer 48

Stippling