Diagnosis and Plant Diagnosis and Plant Disorders Disorders Mark Grueber, Urban Forester Mark Grueber, Urban Forester Missouri Department of Conservation Missouri Department of Conservation [email protected] [email protected]
Jun 20, 2015
Diagnosis and Plant DisordersDiagnosis and Plant Disorders
Mark Grueber, Urban ForesterMark Grueber, Urban Forester
Missouri Department of ConservationMissouri Department of Conservation
[email protected]@mdc.mo.gov
ObjectivesObjectives Distinguish between plant problems caused by living Distinguish between plant problems caused by living
and nonliving disorders.and nonliving disorders. Understand the principles of a systematic approach to Understand the principles of a systematic approach to
the plant diagnostic process.the plant diagnostic process. Learn to recognize the signs and symptoms of tree Learn to recognize the signs and symptoms of tree
disorders.disorders. Learn the various physiological disorders and injuries Learn the various physiological disorders and injuries
that can affect trees, and learn what treatments are that can affect trees, and learn what treatments are appropriate.appropriate.
Become familiar with various types of insect and Become familiar with various types of insect and disease problems and their impact on trees.disease problems and their impact on trees.
This is NOT an entomology and This is NOT an entomology and pathology class!pathology class!
Various plant pest classes are available at St. Various plant pest classes are available at St. Louis Community College @ MeramecLouis Community College @ Meramec
References can be a big help but References can be a big help but overwhelmingoverwhelming
Key TermsKey Terms
The Key Terms as listed in The Key Terms as listed in the Arborist’s the Arborist’s Certification Study Certification Study Guide will be defined Guide will be defined and and highlightedhighlighted throughout the throughout the presentation.presentation.
Challenges to diagnosisChallenges to diagnosis
Trees don’t talk!Trees don’t talk! Asking all the necessary Asking all the necessary
questionsquestions History is hard (or History is hard (or
impossible) to come byimpossible) to come by Tree owners don’t have Tree owners don’t have
a clue!a clue! Paradigm shift?Paradigm shift? Most of the time – it’s Most of the time – it’s
too latetoo late
What is disease?What is disease?
1.1. An impairment of health or a condition of abnormal An impairment of health or a condition of abnormal functioningfunctioning
2.2. Includes Includes anythinganything that damages plant health that damages plant health
Two Major Groups of Plant Health Two Major Groups of Plant Health ProblemsProblems
BioticBiotic – pertaining to a living organism; e.g. fungi, – pertaining to a living organism; e.g. fungi, bacteria, viruses and bacteria, viruses and nematodesnematodes [microscopic [microscopic roundworm] roundworm] as well as insect pests, mites, and other as well as insect pests, mites, and other animals; a.k.a. animals; a.k.a. infectious infectious as they can spread from one as they can spread from one plant to the next.plant to the next.
Abiotic Abiotic – – non living; a.k.a. non-infectious and include non living; a.k.a. non-infectious and include environmental problems such temperature and environmental problems such temperature and moisture extremes, mechanical and chemical injuries, moisture extremes, mechanical and chemical injuries, mineral deficiencies and many othersmineral deficiencies and many others
Diagnosis is a systematic processDiagnosis is a systematic process
A good diagnostician is A good diagnostician is a keen observer that a keen observer that looks at things logicallylooks at things logically
Unfortunately, we tend Unfortunately, we tend to shortcut the processto shortcut the process
Good diagnosis requires Good diagnosis requires careful examination and careful examination and systematic elimination systematic elimination of possibilitiesof possibilities
Systematic Steps to DiagnosisSystematic Steps to Diagnosis
1.1. Accurately identify the plant.Accurately identify the plant.
2.2. Look for a pattern of abnormality.Look for a pattern of abnormality.
3.3. Carefully examine the site.Carefully examine the site.
4.4. Note the color, size and thickness of the Note the color, size and thickness of the foliage.foliage.
5.5. Check the trunk and branches.Check the trunk and branches.
6.6. Examine the roots and root color.Examine the roots and root color.
1. Accurately identify the plant.1. Accurately identify the plant.
So, is this “normal?”So, is this “normal?”
2. Look for a pattern of abnormality.2. Look for a pattern of abnormality.
Non uniform usually = living causal Non uniform usually = living causal agentagent
Uniform usually = non-living causal Uniform usually = non-living causal agentagent
3. Carefully examine the site.3. Carefully examine the site.
Never underestimate site factors!Never underestimate site factors!
4. Note the color, size, and thickness 4. Note the color, size, and thickness of foliage.of foliage.
Various leaf irregularities may give Various leaf irregularities may give you a clue…you a clue…
5. Check the trunk and branches.5. Check the trunk and branches.
What caused this damage?What caused this damage?
6. Check the roots and root collar.6. Check the roots and root collar.
This frequently overlooked area is This frequently overlooked area is often the “root of the problem.”often the “root of the problem.”
Healthy roots and dead rootsHealthy roots and dead roots
What root/soil investigation can What root/soil investigation can show you…show you…
pH????
pH!!!
As you go through the process, try to As you go through the process, try to eliminate certain possibilities…eliminate certain possibilities…
???
X X
……and an opportunistic leaf spot. and an opportunistic leaf spot. Poor tree health is rarely the result Poor tree health is rarely the result of one condition, but rather a of one condition, but rather a complex complex [a combination of factors [a combination of factors that lead to the stress of decline of a that lead to the stress of decline of a tree] of abiotic and biotic tree] of abiotic and biotic contributors. Stress this to the tree contributors. Stress this to the tree owner!owner!
In Diagnosis, practice makes In Diagnosis, practice makes perfect…well, better.perfect…well, better.
The more you do diagnosis (properly), the The more you do diagnosis (properly), the better you’ll get.better you’ll get.
Don’t commit! Keep an open mind.Don’t commit! Keep an open mind. Look for the initial stressor – not necessarily Look for the initial stressor – not necessarily
what the tree owner is complaining about.what the tree owner is complaining about. NEVER, NEVER guess!NEVER, NEVER guess! Seek assistance – MDC, MoBot, SLCC, UMCSeek assistance – MDC, MoBot, SLCC, UMC
Diagnostic Process – Questions?Diagnostic Process – Questions?
Symptom vs. SignSymptom vs. Sign
SymptomSymptom – a plant’s reaction to a disorder– a plant’s reaction to a disorder SignSign – the physical evidence of a causal agent – the physical evidence of a causal agent
Symptom or Sign?Symptom or Sign?
Symptom or Sign?Symptom or Sign?
Symptom or Sign?Symptom or Sign?
Leaf spot – Leaf spot – patches of disease or patches of disease or other damage on plant foliageother damage on plant foliage
Size, shape and color Size, shape and color may varymay vary
Usually limited to a Usually limited to a small portion of the leafsmall portion of the leaf
Leaf blotchLeaf blotch – – irregularly shaped irregularly shaped areas of disease on plant foliageareas of disease on plant foliage
Larger than leaf spotsLarger than leaf spots Usually involves mostly Usually involves mostly
dead tissuedead tissue
BlightBlight – – any disease, regardless of any disease, regardless of causal agent, that kills young, plant causal agent, that kills young, plant
growing tissuesgrowing tissues
Involves death of leaves Involves death of leaves and twigsand twigs
A misused and A misused and misunderstood termmisunderstood term
ScorchScorch – – browning and shriveling of browning and shriveling of foliage, especially at the leaf marginfoliage, especially at the leaf margin
Tend to think of this Tend to think of this symptom related to symptom related to abiotic disordersabiotic disorders
Oak wilt foliage, Oak wilt foliage, bacterial leaf scorch bacterial leaf scorch (buckeye and oak)(buckeye and oak)
WiltWilt – loss of turgidity and – loss of turgidity and subsequent drooping of leavessubsequent drooping of leaves
Can look similar to Can look similar to blightblight
Leaves may or may not Leaves may or may not be deadbe dead
CankerCanker – – localized diseased area, localized diseased area, often shrunken and discolored, on often shrunken and discolored, on
stems and branchesstems and branches
Perennial vs. diffusePerennial vs. diffuse Another confused termAnother confused term
StuntingStunting – – growth reduction of growth reduction of organisms, in this case, plantsorganisms, in this case, plants
Be careful that it’s not Be careful that it’s not just new growthjust new growth
Foliage size can be Foliage size can be extremely variableextremely variable
Not just foliageNot just foliage
GummosisGummosis – – exudation of sap or exudation of sap or gum, often in response to disease or gum, often in response to disease or
insect damageinsect damage
Called Called resinosisresinosis in in conifersconifers
Sometimes found in Sometimes found in combination with combination with cankerscankers
RustRust – – disease caused by a certain disease caused by a certain group of fungi and characterized by group of fungi and characterized by
reddish brown spotsreddish brown spots
Can also form galls and Can also form galls and cankerscankers
GallGall – – swelling of plant tissues; swelling of plant tissues; frequently caused by insects frequently caused by insects nematodes, fungi, or bacterianematodes, fungi, or bacteria
Galls are a plant Galls are a plant response – not a cocoonresponse – not a cocoon
ChlorosisChlorosis – – whitish or yellowish whitish or yellowish discoloration caused by lack of discoloration caused by lack of
chlorophyll; often used in referring chlorophyll; often used in referring to a plant’s foliageto a plant’s foliage
Why is a lack of chlorophyll a problem?Why is a lack of chlorophyll a problem?
NecrosisNecrosis – – localized death of tissue in localized death of tissue in a living organisma living organism
DiebackDieback – – condition in which the condition in which the ends of the branches are dyingends of the branches are dying
Powdery MildewPowdery Mildew – white or grayish – white or grayish fungal growth on the surface of fungal growth on the surface of
stems or foliagestems or foliage
Vascular discolorationVascular discoloration – darkening of – darkening of the vascular tissues of woody plants the vascular tissues of woody plants
in response to diseasein response to disease
Witch’s broomWitch’s broom – plant disorder in – plant disorder in which a large number of accessory which a large number of accessory shoots developshoots develop
Trivia – what type of plants Trivia – what type of plants are sometimes created from are sometimes created from witch’s brooms?witch’s brooms?
Symptoms can be non-specificSymptoms can be non-specific
Will investigating this Will investigating this spot lead to a proper spot lead to a proper diagnosis?diagnosis?
Use other conditions Use other conditions (site, history etc.) to (site, history etc.) to form diagnosisform diagnosis
Signs and Symptoms Questions?Signs and Symptoms Questions?
Tree stressTree stress
Necessary basic factors: Necessary basic factors: sufficient water, optimal sufficient water, optimal temperature and light, temperature and light, and proper balance of and proper balance of nutrients – (Liebig’s law nutrients – (Liebig’s law of the minimum)of the minimum)
StressStress – factor that – factor that negatively affects the negatively affects the health of a treehealth of a tree
Acute stressAcute stress
Short termShort term Causes immediate Causes immediate
damagedamage More likely to recover?More likely to recover? AcuteAcute – disorder or – disorder or
disease that occurs disease that occurs suddenly or over a short suddenly or over a short period of timeperiod of time
ChronicChronic stress stress
Disorder or disease Disorder or disease occurring over a long occurring over a long period of timeperiod of time
How stress exhibits itselfHow stress exhibits itself
Reduced growthReduced growth Abnormal foliage color Abnormal foliage color
or sizeor size Vigorous watersproutsVigorous watersprouts Premature leaf dropPremature leaf drop Others?Others?
Common causes of stressCommon causes of stress
Site and/or environment Site and/or environment relatedrelated
Right tree, right place!Right tree, right place! HH22O, extreme cold, O, extreme cold,
adverse soil conditions adverse soil conditions (compaction), or (compaction), or mechanical damagemechanical damage
Can you “save” my tree?Can you “save” my tree?
Stress Questions?Stress Questions?
Break???Break???
Abiotic DisordersAbiotic Disorders
Often the primary stress factor(s) that cause Often the primary stress factor(s) that cause the spiral of declinethe spiral of decline
Can be difficult to recognize – often mimic Can be difficult to recognize – often mimic biotic disorders and are part of a complexbiotic disorders and are part of a complex
Tree and site history often give the best cluesTree and site history often give the best clues
Types of abiotic disordersTypes of abiotic disorders
Soil and site problemsSoil and site problems Physical and mechanical Physical and mechanical
injuriesinjuries Temperature extremesTemperature extremes Competition and Competition and
allelopathyallelopathy Pollution damagePollution damage Chemical injuryChemical injury
Soil and Site ProblemsSoil and Site Problems
Similar to root disorders Similar to root disorders this is commonly this is commonly overlookedoverlooked
Crown symptoms often Crown symptoms often are a result of poor root are a result of poor root healthhealth
““Transplant shock”Transplant shock” Urban soilsUrban soils
Physical and Mechanical InjuriesPhysical and Mechanical Injuries
Not Not physiological physiological disorderdisorder [a disorder not [a disorder not caused by insect, caused by insect, pathogen or injury]pathogen or injury]
Sudden injurySudden injury Extent of damage may Extent of damage may
initially be difficult to initially be difficult to assessassess
Very frustrating for tree Very frustrating for tree ownersowners
Competition and AllelopathyCompetition and Allelopathy
Plants are “vicious Plants are “vicious killers”killers”
Sunlight is usually the Sunlight is usually the primary factor resulting primary factor resulting in defect, reduced in defect, reduced growth or diebackgrowth or dieback
Available growing Available growing space is common space is common limiting factor in heavy limiting factor in heavy urban areasurban areas
Pollution DamagePollution Damage Acute and chronic injuryAcute and chronic injury Other factors: wind, Other factors: wind,
humidity, soil grade and humidity, soil grade and type, precipitation levels, type, precipitation levels, and conditionand condition
Mimic insect injury and Mimic insect injury and mineral deficienciesmineral deficiencies
Four major airborne Four major airborne pollutants: SOpollutants: SO22, fluoride, , fluoride,
ozone and PANozone and PAN Usually evident on foliageUsually evident on foliage
Chemical InjuryChemical Injury
Herbicides applied improperly most frequent culpritsHerbicides applied improperly most frequent culprits Trees are “broadleaf weeds”Trees are “broadleaf weeds” 2,4-D and dicamba work 2,4-D and dicamba work systemicallysystemically [substance that moves [substance that moves
throughout and is absorbed by the entire organism]throughout and is absorbed by the entire organism]
Biotic DisordersBiotic Disorders
Insects and Other PestsInsects and Other Pests Disease (in this case: fungi, bacteria, Disease (in this case: fungi, bacteria,
phytoplasmas, etc.)phytoplasmas, etc.)
What is an insect?What is an insect?
NOT an insect!NOT an insect!
Insects…Insects…
may or may not be host specificmay or may not be host specific may be predatory or parasitic on species of may be predatory or parasitic on species of
harmful insectsharmful insects have complex life cycles that may have both have complex life cycles that may have both
harmful and innocuous stagesharmful and innocuous stages most species have little to no effect on plant most species have little to no effect on plant
life – a fact that the tree owner may find life – a fact that the tree owner may find difficult to understanddifficult to understand
Feeding damage is characterized by Feeding damage is characterized by the mouthpartsthe mouthparts
Chewing – leaves, flowers, buds, twigs, stems Chewing – leaves, flowers, buds, twigs, stems (borers)(borers)
Piercing-sucking – leaves, flowers, buds, twigs Piercing-sucking – leaves, flowers, buds, twigs and stemsand stems
Chewing InsectsChewing Insects
May feed on entire leafMay feed on entire leaf May feed on leaf May feed on leaf
marginsmargins May May skeletonizeskeletonize [leaves [leaves
that have had the tissue that have had the tissue removed from between removed from between the veins by inects]the veins by inects]
May tunnel between May tunnel between leaf tissuesleaf tissues
May bore through woodMay bore through wood
““Marginal” feedersMarginal” feeders
Piercing-sucking Insects(?)Piercing-sucking Insects(?)
Some pierce plant cells Some pierce plant cells and feed on the contentsand feed on the contents
May also cause May also cause phytotoxic effects from phytotoxic effects from secreted chemicalssecreted chemicals
Usually don’t kill trees Usually don’t kill trees outright, but cause outright, but cause stressstress
Ewwww! Bug poop!Ewwww! Bug poop! Don’t forget the mites!Don’t forget the mites!
ScalesScales
Others…Others…
Insects…Insects…
Can also be Can also be vectorsvectors [organism that transmits a] [organism that transmits a] pathogenpathogen [causal agent of a disease] [causal agent of a disease]
NematodesNematodes
Microscopic Microscopic roundworms most of roundworms most of which are not parasites which are not parasites of plantsof plants
Important for organic Important for organic decaydecay
May enter tree through May enter tree through roots, wounds, stomata, roots, wounds, stomata, or directly into plant or directly into plant cellscells
DiseasesDiseases
Four requirements are Four requirements are necessary for a pathogen to necessary for a pathogen to infectinfect
Most pathogens are host Most pathogens are host specificspecific
The afflicted plant part will The afflicted plant part will give an indication of the give an indication of the severity of diseaseseverity of disease
Most plant diseases are Most plant diseases are caused by fungicaused by fungi
FungiFungi
Most plant diseases are caused by fungi.Most plant diseases are caused by fungi. Not all are bad! Don’t forget mycorrhizae.Not all are bad! Don’t forget mycorrhizae. Almost every plant can be infected by fungi – Almost every plant can be infected by fungi –
most are to some extent during the growing most are to some extent during the growing season.season.
Infection severity and extent depends on the Infection severity and extent depends on the resistance and vitality of the plant.resistance and vitality of the plant.
Diseases that cause Diseases that cause defoliationdefoliation – loss – loss of leaves from a tree or other plant of leaves from a tree or other plant by biological or mechanical meansby biological or mechanical means
Vascular DiseasesVascular Diseases
BacteriaBacteria
Only two of major Only two of major importanceimportance
Infected plant tissues Infected plant tissues may appear water may appear water soaked and have a foul soaked and have a foul odorodor
Phytoplasmas and Phytoplasmas and VirusesViruses
Used to be called Used to be called Mycoplasma like Mycoplasma like organisms (MLOs) now organisms (MLOs) now PLOsPLOs
Not much is knownNot much is known No important viral No important viral
diseases on treesdiseases on trees
How can I be learn more?How can I be learn more?
MDC Plant Diagnostic Lab – Dr. Bruce Moltzan MDC Plant Diagnostic Lab – Dr. Bruce Moltzan (Pathologist) and Dr. Rob Lawrence (Entomologist)(Pathologist) and Dr. Rob Lawrence (Entomologist)
Updates: My e-mail list: Updates: My e-mail list: [email protected]@mdc.mo.gov Community Tree CouncilCommunity Tree Council Missouri ForestKeepers Network: Missouri ForestKeepers Network:
www.forestkeepers.orgwww.forestkeepers.org How to take a sampleHow to take a sample ReferencesReferences
Now that I know…Now that I know…
It’s all about preventionIt’s all about prevention Too much improper pesticide useToo much improper pesticide use More next week!More next week!