Lawn & Landscape Disease Library

Leyland Cypress

Seiridium canker

A serious fungal disease affecting Leyland cypress trees, Seiridium canker causes branch dieback, resin oozing, and browning foliage, often starting o...

Tobacco streak

Rose mosaic

This deciduous shrub typically features glossy, dark green leaves with a dense, rounded growth habit, making it a popular choice for hedges and founda...

Daylily

Daylily rust

Known for their vibrant, trumpet-shaped blooms and grass-like foliage, daylilies (Hemerocallis spp.) are hardy perennials commonly used in Middle Tenn...

Dollarspot

Small, circular patches of bleached or straw-colored turf are classic signs of dollar spot, a common turfgrass disease caused by the fungus Clarireedi...

Fairy Ring

Fairy ring is a common turf disease characterized by circular rings or arcs of dark green, lush grass often accompanied by mushrooms or dead grass pat...

Fire Blight

Bacterial disease associated

Causes shephard’s crook Can cause cankers...

. most affected

Prunus spp

Forms galls/knots on branches and Fungal fruiting structure formed on surface of galls...

2,4-D Herbicide Injury

Yellowing, leaf cupping, and distorted growth often indicate 2,4-D herbicide injury, which occurs when this common broadleaf weed killer drifts onto s...

Aeration Deficit or Oxygen Stress

Oxygen stress is caused by an insufficient supply or availability of oxygen to root system. Pore space is occupied by other substances (water, natural...

Air Pollution Injury

Leaves in affected lawns and gardens often display yellowing, browning, or spotting due to exposure to air pollutants like ozone and sulfur dioxide. T...

Anthracnose - Red Maple

This fungal disease causes irregular, dark, sunken lesions on leaves, twigs, and branches of red maples (Acer rubrum), leading to premature leaf drop ...

Anthracnoses

This fungal disease causes dark, sunken lesions on leaves, stems, and fruit, often leading to premature leaf drop and reduced plant vigor. Anthracnose...

Apple Scab

Fruit symptoms are rare in Colorado

-requires high humidity to develop...

Armillaria Root Rot

This fungal disease causes white mycelial growth and honey-colored mushrooms at the base of infected trees, leading to root decay and decline in vigor...

Armillaria Root Rot - Rose

White fungal growth under bark

White fungal growth beneath the bark signals Armillaria root rot, a serious fungal disease that attacks rose plants by decaying their roots and lower ...

Armillaria Root Rot -Oak

This fungal disease causes white mycelial growth and honey-colored mushrooms at the base of oaks, leading to root decay and tree decline. It thrives i...

Armillaria Root Rot – Oakleaf Hydrangea

This fungal disease causes white, fan-shaped mycelial growth under the bark and decayed roots, leading to wilting and dieback in oakleaf hydrangea (Hy...

Ash Yellows

Caused by a phytoplasma

This disease, caused by a phytoplasma, leads to yellowing and thinning of ash tree leaves, often accompanied by branch dieback. It primarily affects a...

Aster Yellows

This disease causes yellowing, stunted growth, and malformed flowers in a wide range of plants, especially asters and carrots. It is caused by a phyto...

Azalea Leaf Gall

Occurs in cool, moist springs

Affected azaleas develop thick, fleshy, and distorted leaves due to the fungal pathogen Exobasidium vaccinii, especially during cool, moist springs co...

Bacteria

Through wounds

Natural openings Single-celled Reproduce by cell division Spread by infested planting material, plant debris, soil, water, air, infested...

Bacterial Diseases

Fireblight of Apples and Pears

Xanthomonas Leaf Spot of English Ivy...

Bacterial Leaf Spots

Bacterial leaf spots cause small, water-soaked lesions that often enlarge and turn brown or black, leading to leaf yellowing and premature drop. This ...

Bacterial Wetwood

Caused by several species of bacteria

Characterized by brown streaks & oozing No control methods...

Before

Before mid-1960s: fungicides were protectives, use

Prior to the mid-1960s, fungicides were primarily used as protective treatments, applied before disease symptoms appeared to prevent fungal infections...

Biotic factors affecting ornamentals

Disease caused by pathogens/living organisms

Diagnose based on symptoms & signs...

Biotic Problems

Phytoplasma type organisms

Phytoplasma-type organisms cause biotic problems characterized by yellowing, stunted growth, and abnormal leaf development in various ornamental and f...

Blackspot Of Rose

This fungal disease causes round black spots with fringed edges on rose leaves, leading to yellowing and premature leaf drop. Thriving in warm, wet co...

Blight of

Juniper and Cedar

Control of Phomopsis Prune away diseased parts. Avoid lawn watering during Apply fungicides in spring....

Blue Stain Fungi

This fungal disease causes dark discoloration in the sapwood of pine and other conifer trees, often visible after logging or storm damage. Blue stain ...

Boston Ivy Leaf Spot

Leaf spot on Boston ivy presents as small, dark brown to black lesions on the foliage, often surrounded by yellow halos. This fungal disease thrives i...

Botryosphaeria Canker

This fungal disease causes sunken, dark cankers on tree branches and trunks, often leading to dieback and decline in affected plants. It primarily tar...

Boxwood - Cortex sloughing/root rot

This disease causes the bark on boxwood shrubs (Buxus spp.) to peel away, exposing discolored and decaying wood beneath, while root rot leads to wilti...

Brown Patch Of Turf

Brown Patch of Turf, caused by the fungus Rhizoctonia solani, appears as circular, brown, and thinning patches in warm-season lawns common across Midd...

Bugs and Plants

Identifying and Managing

In Middle Tennessee lawns and gardens, identifying plant damage caused by bugs is crucial for effective management. Symptoms such as chewed leaves, di...

Camellia Leaf Gall

Camellia leaf gall early symptoms and last

Early symptoms of Camellia leaf gall appear as pale green, thickened, and fleshy leaf tissues that eventually turn white and then brown as the disease...

Cedar

Cedar apple rust on crabapple

A fungal disease affecting crabapple trees, cedar apple rust causes bright orange-yellow spots on leaves and fruit, leading to premature leaf drop and...

Cedar Quince Rust

This fungal disease causes bright orange to reddish pustules on the leaves and fruit of quince and related plants, often leading to defoliation and re...

Cedar-apple

Cedar-apple rust

This fungal disease causes bright orange, gelatinous galls on cedar trees and yellow-orange spots with black dots on apple leaves, leading to prematur...

Cercospora

Cercospora leaf spot on Hydrangea

Leaf spot caused by Cercospora fungi appears as small, round, brown or purple lesions on hydrangea leaves, often leading to premature leaf drop. This ...

Cercospora Leaf Spot

Circular or angular dark brown spots

This fungal disease causes circular or angular dark brown spots on the leaves of various plants, often leading to premature leaf drop and reduced vigo...

Cercospora Leaf Spot - Dogwood

Dark brown to black circular spots with purple halos typically appear on dogwood leaves infected by Cercospora leaf spot (Cercospora spp.). This funga...

Cercospora Leaf Spot – Crape Myrtle

Cercospora leaf spot causes small, dark brown to purple lesions on crape myrtle leaves, often leading to premature leaf drop and reduced flowering. Th...

Check

This fungal disease causes dark, circular lesions with concentric rings on leaves, leading to premature leaf drop and weakened plant health. It common...

Common Shrubs

Powdery Mildew of Honeysuckle Crape Myrtle Susceptible Shrubs...

Control of Bacterial Diseases

Accept and use only disease

free propagation material. Prune out affected plant parts or rogue infected plants when applicable. Apply antibiotics or coppers....

Control of Dutch Elm Disease

Plant resistant elms.

Remove infested trees. Injection may prevent DED from spreading to nearby trees or cure trees with <15%...

Control of Fungal Foliar Diseases

Use resistant cultivars, if available.

Apply fungicides at appropriate Avoid irrigating foliage, if possible. Gather and destroy diseased foliage....

Control of Hypoxylon Canker

Avoid soil compaction, site

disturbances, and drought stress. Promote tree vigor. Remove disease branches and trees to lower inoculum levels....

Control of Pine Wilt

Plant only resistant pines.

before May when pine sawyers become active. Remove infested trees Native pines (pinyon, loblolly, shortleaf) are more resistant....

Control of Root Rots

Select vigorous plants

from nursery. Promote good drainage. Chemical control is usually ineffective. Replant with resistant...

Control of Stem Cankers

Avoid problem kinds of trees.

Prune away affected parts. Avoid wounds caused by lawnmowers and weed trimmers Prune properly to minimize wounding and promote healing....

Control of Viral Diseases

Accept and use only disease free

propagation material. Maintain good sanitation; remove and destroy diseased plants. Control insect vectors when For mechanically transmitted...

Critter Facts

You may think their stuff is crap,

of the bugs are innocuous. 8% impact plant appearance (aesthetics) 2% can harm plant health – 1.8% are attracted to stressed plants – 0.2% can actuall...

Cytospora or Leucostoma Canker

This fungal disease causes sunken, discolored cankers on tree bark, often oozing a gummy substance. It primarily affects fruit and shade trees, includ...

Deep Planting or Covered Later

Check for flare at base of trunk

When planting trees or shrubs in Middle Tennessee areas like Franklin or Brentwood, avoid deep planting or covering the root flare with soil or mulch....

Defoliation

Defoliation refers to the premature loss of leaves, often caused by fungal infections, insect damage, or environmental stress. This condition weakens ...

Defoliators

Defoliators are insects that feed on the leaves of trees and shrubs, causing significant leaf loss that weakens plants and reduces their ability to ph...

Diagnosing Pine Wilt

Symptoms typically

appear August through Needles turn yellow/brown and remain attached to tree. Tree dies relatively...

Diagnosing the Problem

Correct identification of the cause of poor plant health is essential to formulating effective of poor plant health can sometimes be difficult....

Diagnosis Can Be Tricky Without All The Facts

Diagnosing lawn diseases in Middle Tennessee can be challenging without a complete understanding of symptoms, environmental conditions, and recent law...

Diagnositc Tools and Resources

Shovel Soil probe Bags, jars, bottles, vials to collect samples Portable pH meter Pocket knife, Hand pruner Hand lens Camera, Notebook or tape recorde...

Disease Types

Foliar pathogens

Surface molds (mildews) Stomatal infecting (foliar blight & rust) Tissue infecting (necrosis, mosaics & rusts) Gall tissue formation Reduce photosynth...

Diseases Caused by Bacteria

Spread by rain water,

insects, infected propagation material or tools Symptoms include spots, blights, and abnormal growths such as galls and rosettes...

Diseases Caused by Viruses

Symptoms include

spots, ring spots, stippling, mosaics, stunting, yellowing, distortions, abnormal proliferation...

Diseases Of Landscape Ornamentals

Viral Diseases Bacterial Diseases Fungal Foliar Diseases Stem Blights and Cankers Vascular Wilts...

Diseases of Ornamental Flowers

Fungal diseases

Viral diseases Bacterial diseases Tend to grow outward from center-look for concentric rings; spores; fruiting bodies, fluffy mycelium growth, pustule...

Diseases of Ornamental Woody Plants

Hardwood more likely to recover than conifers

-Foliage Diseases secondary problems All diseases will stress a tree and can lead to...

Diseases of Woody Plants

Produce orange/rust colored spores during life

needed for infection Conifers & some hardwoods are affected Usually require alternate hosts to complete life Spores spread by wind; rain and high humi...

Dogwood Anthracnose

Different disease than spot anthracnose

This fungal disease causes tan to brown irregular blotches with purple margins on dogwood leaves, often leading to premature leaf drop and twig diebac...

Dr. Elizabeth Little

Department of Plant Pathology

Dr. Elizabeth Little specializes in plant pathology, focusing on diagnosing and managing diseases that affect lawns and landscapes in Middle Tennessee...

Dutch Elm Disease

Fungal disease spread by beetle

(which beetle?) European elm bark beetle Causes wilt and tree death when xylem becomes colonized...

Dwarf Mistletoe

Parasitic plant on pines and

Douglas-Fir Robs nutrients Causes “brooming”...

Early fall color

Loose bark at soil line

Trunk girdling Root collar rot Occurs on Honeylocust Not much known about disease cycle...

emerge

Causes galls on

Cedar-Knot-Gall-Rust Juniper, alternate hosts are apples, hawthorn, crabapples, & others from galls (spore...

Entomosporium

This fungal disease causes distinctive red to purple leaf spots with dark centers, primarily affecting photinia and other ornamental shrubs common in ...

Forms cleistothecia (fungal

fruiting structures used to id) Powdery Mildew (on lilac)...

Fungal Foliar Diseases

Powdery Mildews Needle Blights Anthracnoses...

Fungi

Sexually reproduced or asexually reproduced

Direct penetration Through wounds Hyphae and Mycelium Reproduce by spores Fruiting structures...

Fusarium Blight Turf

Fusarium blight, caused by Fusarium spp., appears as sunken, water-soaked lesions that rapidly turn brown on turfgrass, often forming circular patches...

Glyphosate Herbicide Injury

Symptoms of glyphosate herbicide injury include yellowing, curling, and distorted leaf growth, often appearing on broadleaf plants in lawns and garden...

History

History of Fungicide Use

Fungicides have been used for over a century to protect plants from fungal diseases by inhibiting spore germination and fungal growth. Their developme...

Hydrangea – Leaf Spot

Leaf spot on hydrangeas causes small, brown to purple spots on leaves, often surrounded by yellow halos, leading to premature leaf drop. This fungal d...

Hypoxylon Canker

Hypoxylon canker of oak

This fungal disease causes sunken, discolored cankers on oak tree bark, often leading to branch dieback and wood decay. Hypoxylon canker thrives in st...

Identifying Plant Diseases

Plant diseases often present as discolored spots, wilting, or unusual growths on leaves, stems, or roots, affecting overall plant health. These diseas...

Identification. Infestations

There is a white line on the back

can be easily identified by the silk tents that are found in branch crotches. The occurrence of the silk tents may be associat- ed with the gradual los...

Identification. The disease

However, severe infections result

can be identified by the white to orange colored bladder-like blis- ters that are produced on the nee- dles (Figure 1). These blisters are full of spor...

Identification. The most

obvious sign of infection on cedar is the orange, rubber-like galls that look like “an octopus gone mad.” The orange tendrils that comprise the gall s...

Identification. These fungi

Later in the season, the infec-

infect the newly emerging nee- dles in the spring or summer, causing a small yellow discol- oration on the needle (Figure 3)....

Identification. You can

identify the larval stage of the redheaded pine sawfly by its bright red head. The mature larva is about 2.5 cm in length, has a white to yellow body, ...

Impatiens Necrotic Spot Virus (INSV)

Vectored by thrips

Tomato Spotted Wilt Virus (TSWV) Pesticides won’t control viruses Viral Diseases...

in soil

Has hundreds of hosts

saprophytically Crown Gall (shown on Rose) Caused by a bacteria Can survive Enters plants through wounds (grafting,...

Injury from Climatic Conditions

Freezing Temperatures – blackened foliage, leaf abscission, cambium injury on stems, plants fail to bloom (flower buds killed), roots killed. Sunburn/...

Invertebrates

Invertebrates such as nematodes and certain insect larvae can cause significant damage to lawns and garden plants in Middle Tennessee, including areas...

Japanese MaplePhyllosticta Leaf Spot

This fungal disease causes small, dark purple to black spots with light centers on Japanese maple leaves, leading to premature leaf drop and weakened ...

Know your plant

Bald Cypress...

Leaf lesions

Growth habit affected

Defoliation Anthracnose (on Sycamore)...

Leaf Rust (on Rose)

Orange to reddish pustules appearing on the undersides of rose leaves indicate leaf rust, a common fungal disease in Middle Tennessee gardens like tho...

Leaf Spots

Entomosporium leaf spot

on Photinia Phyllosticta leaf spot on holly...

Less

Less water stays on this protected area

Areas with reduced water retention on turf or plants often experience less fungal disease pressure, as many pathogens require moisture to thrive. In M...

Let’s talk aesthetics

Deformed foliage

Defoliation Strange colors Critter crap Massive amounts of critters Critter scariness or ickyness...

Leyland Cypress Problems

Yellowing and browning needles on Leyland cypress (× Cuprocyparis leylandii) often signal issues like cypress canker or root rot, common in Middle Ten...

Look-Alike Disorders of Water Stress

Salt injury Gas injury Sunburn Wind Herbicide injury Vascular wilt diseases Insect injury – bark beetles, borers, root weevils Wildlife injury – voles...

Low Oxygen Diffusion Rate (ODR)

Oxygen moves through soils by diffusion, areas of high concentration to areas of low concentration. When oxygen is consumed by roots/microorganisms, c...

Marssonina Blight

This fungal disease causes small, dark purple spots on oak leaves that often develop a tan center, leading to premature leaf drop in affected trees. M...

Mycosphaerella

Mycosphaerella leaf spot on iris

Leaf spot caused by Mycosphaerella fungi appears as small, round to irregular brown or tan spots on iris leaves, often with a yellow halo. This diseas...

Needle Blights

Dothistroma Needle Blight of Pine...

Needle Spot

This fungal disease causes small, reddish-brown spots with yellow halos on pine needles, leading to premature needle drop and thinning foliage. It pri...

New Bugs on the Horizon

Introduction of Exotic Bugs

Intentional Unintentional To control exotic plants aka weeds Host switching Killer Bees, Gypsy Moth...

Nitrogen

Deficiency Phosphorus Deficiency...

Non-Infectious Causes of

Poor plant health may be caused by non-

Poor Plant Health infectious factors such as cultural, environmental, or nutritional factors. Iron chlorosis...

Oak Leaf Blister

Raised, blister-like lesions appear on oak leaves during spring, causing distorted growth and premature leaf drop. This fungal disease, common in Midd...

Oak Wilt

This fungal disease causes rapid wilting and browning of oak leaves, often leading to tree death within weeks. It primarily affects red oaks, which sh...

Observation

Observation of Field PatternsAbiotic Problem

Uneven lawn patterns with irregular discoloration or thinning often indicate abiotic problems rather than diseases. These issues stem from non-living ...

Occasional disease

Defoliation over years

Oak Leaf Blister may weaken trees...

Occurs

Occurs in warmer, wet springs

This lawn disease typically emerges in warmer, wet springs common to Middle Tennessee areas like Franklin and Brentwood, where prolonged moisture crea...

of Plant

This fungal disease causes irregular, water-soaked spots that later turn brown and necrotic, often surrounded by yellow halos on leaves and stems. It ...

One leg of the disease triangle

Parasitic higher plants

The Pathogen: Phytoplasmas Viruses/viroids...

Other Stem Cankers

Russian olive

Tubercularia canker on Russian olive Nectria/Thyronectria canker of Russian olive, honey locust, etc....

Parasitic Higher Plants

True plants

No chlorophyll Spread with seed Examples: dodder,...

Pathogen survival

Fungi-mycelium, hyphae, sclerotia, mushrooms

Bacteria-dried or living cells, endospores Viruses, viroids, phytoplasmas-in living tissue...

Pattern

Pattern in landscape

This lawn disease causes irregular, blotchy patches of discolored grass that often appear during warm, humid conditions common in Middle Tennessee are...

Phytophthora 101

Phytophthora species resemble fungi but are not.

This water mold causes root rot and stem cankers in various landscape and garden plants, thriving in poorly drained soils common in Middle Tennessee a...

Phytophthora Blight

This soilborne disease causes dark, water-soaked lesions on stems, leaves, and fruit, often rapidly leading to plant collapse. It primarily affects ve...

Phytophthora Foliage Blight

This disease causes dark, water-soaked lesions on leaves and stems, leading to rapid foliage wilting and dieback. It primarily affects ornamental plan...

Phytophthora root & crown rot

This soil-borne disease causes dark, water-soaked lesions on roots and crowns, leading to wilting and plant decline, especially in poorly drained soil...

Phytophthora Root Rot

Wide host range

Often acquired in nursery Rhododendron...

Phytophthora Root Rot on Boxwood

Phytophthora root rot causes boxwoods to exhibit yellowing leaves, stunted growth, and eventual dieback, primarily attacking the root system. This soi...

Phytophthora Root Rot on Shore Juniper

Phytophthora root rot causes dieback and browning of shore juniper (Juniperus shorei) foliage, often accompanied by root decay and poor growth. This s...

Phytoplasma Disease – Aster Yellows

Aster yellows is a phytoplasma disease that causes yellowing, stunted growth, and distorted leaves and flowers in a wide range of ornamental and veget...

Plant Disease Agents

Living organisms - including fungi, bacteria, viru

Living organisms such as fungi, bacteria, and viruses are common agents that cause plant diseases in Middle Tennessee lawns and gardens. These pathoge...

Plant Disease Triangle

Stressed or

Understanding the Plant Disease Triangle is essential for preventing lawn and garden issues in Middle Tennessee. This concept highlights that disease ...

Planted

Planted too deep

When a tree or shrub is planted too deep, the root flare becomes buried, leading to poor oxygen flow and increased risk of root rot and other diseases...

Plum Pockets

Associated with fruiting structures

Caused by fungus Affects all plum species...

Powdery

Powdery mildew

A white, powdery coating often appears on the leaves, stems, and buds of susceptible plants, indicating powdery mildew infection. This fungal disease ...

Powdery Mildew

A common fungal disease in Middle Tennessee, powdery mildew appears as white, powdery spots on leaves, stems, and buds, often causing distorted growth...

Powdery Mildews

White, powdery fungal growth often appears on leaves, stems, and flowers, causing distortion and premature leaf drop. Powdery mildews thrive in warm, ...

Prior

This disease causes irregular brown spots with yellow halos on turfgrass leaves, leading to thinning and weakened lawns commonly seen in Middle Tennes...

Pycnidia

Tiny, flask-shaped fruiting bodies known as pycnidia produce spores in various fungal diseases affecting turfgrass and ornamental plants common in Mid...

Pythium Blight Of Turf

This turfgrass disease causes rapidly spreading, water-soaked patches that turn brown and thin, often appearing during hot, humid weather common in Mi...

Reference

Classes of Nematicides: Non-fumigants

Non-fumigant nematicides are chemical treatments used to manage nematode populations in soil without releasing harmful gases. These products target ro...

Ring

Ring spot symptom – always a virus disease

Virus-induced ring spot symptoms appear as circular, discolored patches on leaves, often causing mottled or necrotic areas that reduce plant vigor. Th...

Root

Root rot is a common disease affecting many landscape and garden plants in Middle Tennessee, including areas like Franklin and Brentwood. It causes ro...

Root Disease Symptoms

Leaf yellowing and drop

Yellowing and premature leaf drop often signal root diseases affecting lawns and landscape plants in Middle Tennessee, including areas like Franklin a...

Root-knot

This soil-borne disease causes swollen, knotted roots that interfere with water and nutrient uptake, leading to stunted growth and yellowing in many g...

Rust

Rust diseases

Rust diseases cause orange to reddish-brown pustules on leaves, stems, and sometimes fruit, leading to premature leaf drop and weakened plants. These ...

Rusts

Cedar Apple Rust...

Scales

Small, sap-sucking insects known as scales often appear as tiny, immobile bumps on stems and leaves, causing yellowing, wilting, and stunted growth in...

Second leg of disease triangle

Plants may be resistant or susceptible to plant

Stress can affect plants resistance...

Septoria Leaf Spot

This fungal disease causes small, water-soaked spots that enlarge into circular lesions with gray centers and dark borders, primarily affecting tomato...

Shoot blight

Caused by a fungus

Affects Aspens, cottonwoods, poplars Shephard’s crook formed Distorted growth...

Shrubs in Landscapes

Diseases of Trees and

Shrubs in Middle Tennessee landscapes, such as those in Franklin or Brentwood, are susceptible to various fungal diseases like powdery mildew and leaf...

So Why Worry?

Horticulture is about aesthetics

Most people think the only good bug is a dead bug Many things we do in horticulture can influence bug populations We can reduce susceptibility of...

Soil

Soil and Fertility Management

Healthy soil is the foundation for a thriving lawn, providing essential nutrients and proper drainage to support grass growth in Middle Tennessee area...

Some Trees and Shrubs Attacked

Wilting, dieback, and cankers often signal disease affecting various trees and shrubs in Middle Tennessee landscapes like Franklin and Brentwood. Thes...

Sooty Mold

A black, powdery coating often covers leaves and stems when sooty mold develops, resulting from fungal growth on honeydew secreted by sap-sucking inse...

Specific Abiotic Plant Problems

Environmental stresses such as drought, excessive heat, nutrient deficiencies, or soil compaction can cause specific abiotic plant problems, leading t...

Spot Anthracnose

Small reddish spots on bracts and leaves, trees in sun

Small reddish spots appearing on bracts and leaves are typical symptoms of spot anthracnose, a fungal disease that thrives in sunny conditions. This d...

Stem Blights and Cankers

Hypoxylon Canker Other Stem Cankers...

Steps

Steps in Problem Diagnosis

Identifying lawn diseases involves carefully examining symptoms such as discoloration, patchy growth, or unusual spots on grass blades, often seen in ...

Steps to Diagnosis

Abiotic or Biotic Condition

Is there a pattern to the damage? Without a pattern it is often a biotic issue Patterns in the plant(s) Patterns in the landscape Nature tends to be r...

Sterol

Sterol inhibitors: large group of fungicides, wide

Sterol inhibitors are a broad class of fungicides that target fungal cell membrane production, effectively controlling diseases like powdery mildew an...

Sunburn?

Bacterial Leaf Scorch? Anthracnose Fungal Disease? Water Stress From Wind? From a broken irrigation line? From trenching through the root system? Fro...

Symptoms—Above Ground

Appear after roots are diseased

Above-ground symptoms of root diseases often include yellowing leaves, wilting, and stunted growth as the affected roots fail to absorb water and nutr...

Symptoms—Below Ground

Must expose roots for examination

When diagnosing below-ground disease symptoms, homeowners should look for root discoloration, decay, or a mushy texture by carefully exposing the root...

Systemic

Systemic and/or curative activities Benomyl (Benla

Systemic fungicides like Benomyl (Benlate) penetrate plant tissues to control fungal diseases by inhibiting spore germination and mycelial growth. Eff...

Third leg of disease triangle

Pathogens require specific temperatures

The Environment: May affect plant stress Affects growth Affects pathogen spore production or growth Affects spread (rain)...

Tip Blight of Pine

Tip blight of pine causes browning and dieback of new shoots, often affecting species like Austrian and Scotch pines common in Middle Tennessee landsc...

tomography

Air knife...

Too

Too late for fungicides

When fungal diseases reach an advanced stage, visible symptoms like extensive leaf spots, wilting, or mold often indicate it's too late for effective ...

Tubercularia & Nectria Cankers

These fungal diseases cause sunken, discolored cankers on the bark of trees, often leading to branch dieback and weakened structural integrity. Tuberc...

Turf Rust

Turf rust is a fungal disease characterized by orange to reddish-brown pustules on grass blades, causing thinning and weakened turf. It commonly affec...

Types

Types of Fungicides

Fungicides are categorized by their mode of action and timing of application, including protectant, systemic, and curative types. Protectant fungicide...

Types of Plant Pathogens

Parasitic plants

Parasitic plants are unique pathogens that attach to host plants, extracting water and nutrients, often causing stunted growth and reduced vigor. Comm...

Uniform Stripes

Observation of Field PatternsRandom vs. Uniform

Uniform stripe patterns in turfgrass often indicate a disease infection that spreads evenly across a lawn, unlike random patches caused by pests or en...

Vascular Wilts

Dutch Elm Disease Verticillium...

Verticillium Wilt

maple, Russian olive, redbud. Shows rings and blocks in X-section. Control: Replace...

Virus Diseases

Impatiens Necrotic Spotted Wilt...

Viruses

Too small to be seen with ordinary microscope Cann

Viruses are microscopic pathogens that infect plants, causing symptoms like mottled leaves, stunted growth, and distorted foliage. In Middle Tennessee...

Viruses & viroids

Protein coat and

Require living tissue to Spread by insects, humans, seeds, tubers, grafted plants, physical Symptoms: mosaics,...

Viruses – no cure, inspect planting material

Viral diseases in lawns and garden plants often cause stunted growth, mottled leaves, and distorted foliage, significantly reducing plant vigor. These...

Water Stress

Abiotic Disorder Bacterial Leaf Scorch Biotic Disorder...

What’s

What’s wrong with my tree?

When a tree in Middle Tennessee shows signs of decline, such as discolored leaves, dead branches, or oozing sap, it may be suffering from common disea...

What’s Wrong With Your Plants and Why?

Unexplained yellowing, wilting, or spotting on leaves often signals plant disease, commonly caused by fungi, bacteria, or viruses thriving in Middle T...

What’s Wrong?

Biotic or Abiotic

When lawn issues arise, determining if the cause is biotic (living pathogens like fungi or insects) or abiotic (non-living factors such as drought or ...

White Pine Blister Rust

Affects five-needle pine; alternate hosts are

goosberry & currant Young trees are most affected Can kill trees, also reduces growth and causes deformities Don’t plant alternate hosts in same area ...

Wilt of Mimosa

This fungal disease causes sudden wilting and yellowing of mimosa trees (Albizia julibrissin), often leading to branch dieback and tree decline. It th...

Witches Brooms

Witches brooms are dense, abnormal clusters of twigs and branches caused by fungal infections, mites, or viruses that deform trees and shrubs. These g...