Diseases

Common name: Anthracnose, crater rot

Scientific name: Colletotrichum gloeosporioides or Colletrotrichum acutatum

The first symptom of antracnose is a small yellowish spot on the fruit surface. This spot gradually grows and becomes a circular, sunken or tan lesion on the surface of the fruit. The decay continues, and in the affected part fruit flesh changes to a grayish black color.

 

anthracnose

  Image from Plant Health Progress article: Identifying and Characterizing Summer Diseases on ‘Babygold’ Peach in South Carolina

Common name: Armillaria Root Rot

Scientific name: Armillaria

Armillaria Root Rot is a soil borne fungal disease. Armillaria Root Rot attacks the root system and crown tissue of plants. The first obvious symptoms are wilting, bronzing and later chlorosis of foliage.  This is followed by foliar collapse/abscission and ultimately tree death.  Upon investigation one will find a well-developed mycelial mat beneath the root bark (rarely extending much above the soil line on the trunk).  Later clusters of gill type mushrooms will appear at the base of dead and dying trees.

armillariaImage from Dr. Tom Beckman USDA-ARS.

More inf.: Armillaria Root and Crown Root

Common name: Bacterial Canker

Scientific name: Pseudomonas syringae

Bacterial Canker affects the twigs and branches of a tree, causing failure of the development of floral and vegetative buds. Other symptoms include elongated cankers.

bacterial canker

Image from Clemson Cooperative Extension website.

More inf.: Bacterial Canker

 

Common name: Bacterial Spot

Scientific name: Xanthomonas arboricola or X. campestris.

This disease may affect foliage, twigs, and fruit. The first symptom is soaked spots on the leaves. This spot may grow darker and become necrotic. Affected leaves turn yellow. Spots also appear on the fruit, causing damage and allowing entrance for other pathogens. To properly identify this pathogen, look for angular lesions on the leaves and fruit.

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Image from Dr. Dario Chavez. University of Georgia. Peach Specialist.

More inf.: Bacterial Spot

 

Common name: Blossom Blight

Scientific name: Monilinia fructicola

Blossom Blight appears when trees begin to bloom and causes blossoms to change from their natural color to a tan or brown color. The blossoms then droop as if they had frost damage. Once the disease starts, it develops quickly and will spread to the twigs, branches, leaves, and fruit. Affected wood may become gummy.

 

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Image from Dr. Dario Chavez. University of Georgia. Peach Specialist.

 

Common name: Botryosphaeria Fruit Rot

Scientific name: Botryosphaeria dothidea

This disease affects the fruit causing circular lesions. This pathogen can be easily confused with anthracnose. However, Botryoshaeria produces softer lesions.

 

botryosphaeria

Image from Plant Health Progress article: Identifying and Characterizing Summer Diseases on ‘Babygold’ Peach in South Carolina

 

Common name: Brown Rot

Scientific name: Monilinia fructicola

Symptoms of brown rot may include blossom and twig blight, cankers, and fruit rot. Shoots infected become sunken and brown. Ripened fruits that become infected develop tan to gray round spots. These spots rot the fruit and grow larger until the entire fruit is infected. The fruit then falls off the tree, or becomes a mummy.

Brown Rot

Image from Dr. Phil Brannen. University of Georgia. Plant pathology.

More inf.: Brown Rot

 

Common name: Crown Gall

Scientific name: Agrobacterium tumefaciens

Crown Gall shows up as abnormal tumors or galls on the roots, or trunk of the tree. New galls are light in color and usually have a soft, spongy texture. The galls become hard and darker with age. Crown gall affects water and nutrient transportation. Therefore, trees affected by crown gall often develop nutrient deficiencies.

 

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Image from Dr. Dario Chavez. University of Georgia. Peach Specialist.

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Common name: Gummosis

Scientific name: Botryosphaeria dothidea

Small blisters on the bark of young trees is an early sign of the disease. Over time, the lesions in these blisters release resin and become sunken into the bark of the tree, forming cankers.

gummosis

Image from Dr. Dario Chavez. University of Georgia. Peach Specialist.

More inf.: Fungal Gummosis

 

Common name: Peach leaf curl

Scientific name: Taphrina deformans

Outbreaks may occur during spring when the weather is cool and moist. Infected leaves become thick, curly, and distorted. In severe cases, defoliation occurs and and fruit yield may be affected.

leaf curl

Image from Clemson Cooperative Extension website.

More inf.: Peach Leaf Curl

 

Common name: Peach Leaf Rust

Scientific name: Tranzschelia

Infections can appear on twigs, leaves, and fruit, but symptoms do not show up until early fall. One of the first symptoms is the developing of twig cankers, which are small blisters and longitudinal splits in the bark. Next, leaf lesions start to appear as bright yellow spots on the surface of the leaves. If you look closely you may even be able to see brown spore masses on the leaves.  Finally, lesions start to appear on the fruit as brown spots with green or greenish yellow halos. These symptoms can be confused with stinkbug damage. To be sure you are dealing with peach leaf rust, look for previous symptoms as well.

rust

 Image from Dr. Phil Brannen, UGA. Clemson Cooperative Extension website.

More inf.: Rust

 

Common name: Peach Scab

Scientific name: Cladosporium carpophilum

Scab damages the fruit appearance and can cause cracking in the peach skin. This cracking allows for other pathogens to enter the fruit and cause additional damage. Peach Scab is easy to identify by the “scabs” or spots of greenish to black color that appear on the surface of the fruit, twigs, shoots and leaves.

 

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Image from Dr. Phil Brannen. University of Georgia. Plant pathology.

More inf.: Peach Scab

 

Common name: Peach Tree Short Life (PTSL)

Scientific name: Pseudomonas spp.

Symptoms of peach tree short life include the sudden wilting and collapse of emerging shoots and flowers during early spring development.  Others symptoms include internal browning and necrosis (bacterial canker or freeze damage) beneath the bark of scaffold limbs and trunk usually accompanied by a strong sour sap odor and trunk leakage.   Severe damage will result in the complete collapse and death of the above ground portion of the tree.  Later the still living root system will often send up numerous suckers.

short life tree

Image from Dr. Tom Beckman. USDA-ARS.

More inf.: Peach Tree Short Life

 

Common name: Phony Peach

Scientific name: Xylella fastidiosa

Symptoms of this disease are not visible until after 18 months of infection. The new growth is heavily reduced, giving the trees a stunted look. Bloom and fruit ripening happens earlier than usual, causing fruit size reduction. Infected bark displays black discoloration. The disease is vectored by leafhoppers.

 

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 Image from Clemson Cooperative Extension website.

More Inf.: Phony Peach

 

Common name: Phytophthora Crown & Root Rot

Scientific name: Phytophora spp.

Phytophthora can be found in trees planted on poorly drained soils. This disease reduces tree growth vigor and causes chlorosis in the leaves. Foliage often becomes reddish or purple, and eventually the pathogen can kill the tree.

 

phytophthora

 Image from Clemson Cooperative Extension website.

More Inf.: Phytophthora Crown & Root Rot

 

Common name: Powdery Mildew

Scientific name: Sphaerotheca pannosa and Podosphaera leucotricha

 Powdery mildew can infect both the leaves and the fruit of a peach tree. When peach leaves are infected, they become shapeless and wrinkled. Diseased fruit develop a white powder on the fruit surface as seen in the picture below.

powdery mildew

Image from Clemson Cooperative Extension website.

More inf.: Powdery mildew

 

Common name: Rhizopus Rot

Scientific name: Rhizopus stolonifer

This rot is one of the biggest issues in post harvest fruit handling, causing major financial losses. To identify this disease, look for the following symptoms on ripened fruit: dark grey fuzz on the surface of the peach.

rhizopus

Image from Clemson Cooperative Extension website.