Peach, Apricot, and Nectarine

Armillaria Root Rot

Fungal Pathogen

Armillaria mellea

Parts of plant affected

Roots

Signs & Symptoms

All of the usual signs of a root disorder will be present, which include: reduced growth, sparse foliage, and stunted, yellow leaves. More specifically: there may be an increased amount of sap around the root collar, black root-like strands in the soil, and fan-shaped fungal mats ranging from dark to light color (typically white to off-white) will form between the wood and bark of infected trunk and root tissues. The most tell-tale sign of armillaria root rot is the formation of honey-colored mushroom clusters near the soil line around the base of the tree.

Photo credit: Andrej Kunca, National Forest Centre – Slovakia, Bugwood.org

Photo credit: Edward L. Barnard, Florida Department of Agriculture and Consumer Services, Bugwood.org

Non-chemical management suggestions

To manage this disease, the best solution is to remove and dispose of the infected tree. To prevent your tree from becoming infected, keep it properly hydrated.

For more information

https://plantdiseasehandbook.tamu.edu/problems-treatments/problems-affecting-multiple-crops/mushroom-root-rot/

References

https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/rot/armillaria-root-rot.aspx

https://extension.umn.edu/plant-diseases/armillaria-root-rot

 

Bacterial Canker

Pathogen

Pseudomonas syringae

Parts of plant affected

Branches, leaves, buds, fruit and shoots.

Signs & Symptoms

Symptoms include: leaf spots, dead buds, twig cankers, and lesions on fruit and/or flowers. Severe cases may cause collapse or death of the tree. The most tell-tale signs are the gum-producing cankers and sour sap (gummosis).

Non-chemical management suggestions

The best way to manage this issue is to prune out infected branches. This helps to prevent the spread of infection while also distancing it from the scaffolds and trunk.  If canker damage is on the tree trunk, consider tree removal.

For more information

https://www.agrilifebookstore.org/Bacterial-Canker-of-Stone-Fruit-p/eplp-002.htm

https://agrilifeextension.tamu.edu/library/gardening/bacterial-canker-of-stone-fruits/

References

https://ecommons.cornell.edu/bitstream/handle/1813/69930/bacterial-canker-stone-FS-NYSIPM.pdf?sequence=2&isAllowed=y

https://www.sid.ir/FileServer/SE/471E201622336.pdf

https://extension.psu.edu/bacterial-canker-of-stone-fruit-in-the-home-fruit-planting

 

Bacterial Spot

Pathogen

Xanthomonas arborico and Xanthomonas pruni

Parts of plant affected

Leaves, fruit, and twigs.

Signs & Symptoms

Symptoms begin to show in late spring-early summer. Small spots will form on the leaves and range in color from dark purple, rust, or black. Over time, the center of the spots fall out leaving shot holes. When spots merge, it can give the leaf a scorched appearance. On the actual fruit, there will be olive or black spots surrounded by water-soaked margins. Spots may enlarge, causing the skin to crack. Twigs may also develop cankers.

Non-chemical management suggestions

Management strategies include: planting trees with sufficient spacing for good air circulation and drainage, pruning trees annually, and fertilizing when needed (balance fertility regiment). 

For more information

https://www.agrilifebookstore.org/Bacterial-Spot-on-Prunus-p/eplp-006.htm

https://agrilifeextension.tamu.edu/library/gardening/bacterial-spot-on-stone-fruit/

References

https://www.jstor.org/stable/pdf/41998761.pdf

https://ohioline.osu.edu/factsheet/plpath-fru-38

 

Brown Rot 

Fungal Pathogen

 Monilia polystroma, Monilinia fructicola, and Monilinia laxa

Parts of plant affected

Fruit, blossoms, leaves, and shoots.

Signs & Symptoms

Blossoms turn brown and become stuck to shoots where the fungal spores are produced. This area will be gummy and range in color from tan to gray. Shoots may develop brown, sunken cankers. These cankers typically form on the new shoots and may also produce the gray/tan fungal spores. New fruit will develop small, spherical spots that eventually become larger. Mature fruits will develop these same spots, but they will enlarge much quicker. These diseases fruits will eventually turn brown or black, shrivel up, and die.

Photo credit: Molly Giesbrecht, Texas A&M AgriLife Extension Service, Bugwood.org

Non-chemical management suggestions

Remove all diseased fruits during the dormant season, prune weak wood during the spring, open up the canopy by pruning, remove stunted fruit, and make sure no mature fruits are touching. 

For more information

https://www.agrilifebookstore.org/Brown-Rot-of-Stone-Fruit-p/eplp-003.htm

https://agrilifeextension.tamu.edu/library/gardening/brown-rot-of-stone-fruits/

References

https://wiki.bugwood.org/Monilinia_(brown_rot_of_stone_fruit)

https://extension.psu.edu/stone-fruit-disease-brown-rot

 

Cotton Root Rot

Fungal Pathogen

Phymatotrichopsis omnivora

Parts of plant affected

Roots

Signs & Symptoms

Symptoms start to occur over the months of June-September. The leaves will dry out and turn brown while remaining attached to the tree. The surface of the roots may have fuzzy brown mold covering them. Another indication is the appearance of spore mats, which are white, spherical patches of mold on the surface of the soil.

Non-chemical management suggestions

Unfortunately, there are not any highly effective management strategies for cotton root rot. The best strategy to prevent this disease is to locate areas infected with Phymatotrichopsis omnivora and plant elsewhere.

For more information

https://plantdiseasehandbook.tamu.edu/problems-treatments/problems-affecting-multiple-crops/cotton-root-rot/

https://agrilifeextension.tamu.edu/wp-content/uploads/2017/01/cotton-root-rot-and-its-management.pdf

References

http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2321/EPP-7621web.pdf

https://aces.nmsu.edu/pubs/_a/A229/welcome.html

 

Crown Gall

Fungal Pathogen

Agrobacterium tumefaciens

Parts of plant affected

Roots, crowns, trunks, and canes.

Signs & Symptoms

Symptoms begin in late spring/early summer with large masses, or galls, appearing on the crown or trunk. Initially, the galls will be spongey, rough, wart like, and white or tan colored. Over time, these galls will harden and darken in color. In severe cases, growth may be stunted and trees will produce poor fruit.

Photo credit: University of Georgia Plant Pathology , University of Georgia, Bugwood.org

Non-chemical management suggestions

There aren’t many non-chemical management strategies, but one way to prevent infection is to minimize damage to the roots, crown and trunk.

For more information

https://plantdiseasehandbook.tamu.edu/problems-treatments/problems-affecting-multiple-crops/crown-gall/

References

https://plantdiseasehandbook.tamu.edu/problems-treatments/problems-affecting-multiple-crops/crown-gall/

https://ohioline.osu.edu/factsheet/plpath-fru-19

 

Fungal Gummosis

Fungal Pathogen

Botryosphaeria dothidea

Parts of plant affected

Shoots, leaves, and bark

Signs & Symptoms

Concave lesions will develop on the bark of the tree. Over time these lesions will enlarge and honey colored sap will ooze out. New leaves and shoots may turn yellow and die as well. Orange fungal strands may grow out of the bark if left untreated.

Photo credit: Ansel Oommen, Bugwood.org

 

 

Photo credit: Carroll E. Younce, USDA Agricultural Research Service, Bugwood.org

 

 

Non-chemical management suggestions

Ways to prevent fungal gummosis include minimizing injury and maintaining proper care of trees.

For more information

https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/cankers/gummosis-of-fruit-trees.aspx

References

https://www.cabi.org/isc/datasheet/9627https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/cankers/gummosis-of-fruit-trees.aspx

 

Leucostoma Canker

Fungal Pathogen

Leucostoma persoonii and Leucostoma cinctum

Parts of plant affected

Twigs, shoots, nodes, trunk, and branches

Signs & Symptoms

On twigs: sunken discolorations appear around leaf buds or dead buds. Usually, the discolorations are surrounded by circles of dead tissue ranging from dark to light colored. 

On nodes: Tissues that are infected begin to turn dark and amber gum oozes out of the infection.

On trunk and branches: Cankers form with excessive gum production. As the infection progresses, the gum oozing from the cankers becomes a darker brown and the infected bark breaks off, revealing black tissue. Branches are also colored with small, black welts that emerge through the infected bark.

Other symptoms: dead scaffold limbs, droopy, yellow leaves, and callus rings around the cankers.

Non-chemical management suggestions

Management suggestions include: creating new orchards, selecting a proper site, maintaining proper care of your orchard, insect control, optimizing the trees’ cold tolerance, and proper pruning.

For more information

https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/LeucostomaCanker.aspx

References

https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/LeucostomaCanker.aspxhttps://extension.umd.edu/hgic/topics/diseases-stone-fruit

 

Oxyporus Root and Crown Rot

Fungal Pathogen

Oxporus latemarginatus

Parts of plant affected

Roots and root collars.

Signs & Symptoms

Infected trees experience reduced or stunted annual growth. Younger trees will experience higher mortality rates compared to older trees. Spongy, white rot will appear on the outer bark and leaves may show signs of chlorosis or yellowing. The inner bark and wood will have reddish-brown discoloration near the crown.

Non-chemical management suggestions

Trees are especially vulnerable during warm weather, specifically when soil is water-logged or feeder roots are damaged. To prevent infection, limit damage to roots and make sure that the soil has adequate drainage.

For more information

https://www.agrilifebookstore.org/product-p/eplp-043.htm

References

https://wiki.bugwood.org/Archive:Sycamore/Oxyporus_latemarginatus

https://ohioline.osu.edu/factsheet/plpath-fru-06

 

Peach Leaf Curl

Fungal Pathogen

Taphrina deformans

Parts of plant affected

Leaves and fruit

Signs & Symptoms

Leaves will take on a shriveled or curled appearance and will vary in color from green, yellow, pink, orange, and purple. Spores produced will give the leaves a dusty appearance. Fruits that are infected will drop prematurely or appear distorted.

Photo Credit: Whitney Cranshaw, Colorado State University, Bugwood.org

Photo Credit: Dr Parthasarathy Seethapathy, Tamil Nadu Agricultural University,

Photo Credit: Paul Bachi, University of Kentucky Research and Education Center, Bugwood.org

Non-chemical management suggestions

Management has to be done in a preventative way, once symptoms begin there is no way to treat the infection. There are no non-chemical management suggestions, the only way to prevent infection is to apply a fungicide or copper spray in the late fall or early spring.

For more information

https://extension.psu.edu/disease-of-the-month-peach-leaf-curl

References

https://extension.umd.edu/hgic/topics/diseases-stone-fruit

https://extension.psu.edu/disease-of-the-month-peach-leaf-curl

 

Peach Mosaic

Pathogen

Virus

Vector

Eriophyes insidiosus

Parts of plant affected

Leaves, fruit, and flowers.

Signs & Symptoms

Mosaic pattern on leaves, petals with deformations and color breaks, deformed fruit, stunted leaves, vein clearing, and twigs that are dwarfed.

Healthy peaches and nectarines on top; infected fruit on bottom. Photo Credit: H.J. Larsen, Bugwood.org

Photo Credit: H.J. Larsen, Bugwood.org

Photo Credit: H.J. Larsen, Bugwood.org

Non-chemical management suggestions

To prevent this infection: use seeds that are certified virus free, remove any plants that could be potential vectors, and remove all infected plants.

For more information

https://agrilifeextension.tamu.edu/library/gardening/peach-latent-mosaic-viroid/

https://www.agrilifebookstore.org/searchresults.asp?Search=peach+mosaic

References

https://apsjournals.apsnet.org/doi/pdf/10.1094/PDIS.1998.82.12.1371

https://wiki.bugwood.org/HPIPM:Viral_Diseases

 

Peach Scab

Fungal Pathogen

Cladosporium carpophilum

Parts of plant affected

Leaves, twigs, and fruit

Signs & Symptoms

Little green spots will appear on the fruit, over time these spots become larger and take on a black color. Typically, these spots will be located near the top of the fruit. On the twigs, infection begins with small red spots. Over time, these spots grow into lesions with raised edges. Leaves will develop yellow spots on their underside. As the tissue on the leaves dies it falls out, leaving shot holes.

Photo Credit: Clemson University – USDA Cooperative Extension Slide Series , Bugwood.org

Photo Credit: Clemson University – USDA Cooperative Extension Slide Series , Bugwood.org

Photo Credit: Clemson University – USDA Cooperative Extension Slide Series , Bugwood.org

Non-chemical management suggestions

Once symptoms begin, there is nothing you can do to stop the infection. To prevent infection: plant in areas with good drainage and prune trees properly and regularly.

For more information

https://agrilifeextension.tamu.edu/library/gardening/peach-scab/

https://www.agrilifebookstore.org/Peach-Scab-p/eplp-008.htm

References

https://extension.psu.edu/peach-disease-scab

https://edis.ifas.ufl.edu/pdf%5CHS%5CHS124900.pdf

 

Peach Yellows

Pathogen

Phytoplasma

Vector

Leafhopper

Parts of plant affected

Leaves and fruit

Signs & Symptoms

Leaf buds and fruit develop prematurely. Fruits will appear larger than normal, but be poor quality and taste bitter. Leaves are typically dwarfed and yellow and the tree starts to grow spindly shoots. 

Symptoms for the little peach strain include: greener foliage at the beginning of the growing season, bush-like appearance of tree, chlorotic leaves as the growing season goes on, and fruit that ripens later than typical healthy fruits. The fruit and pits will be small and the kernels will be underdeveloped. 

Photo Credit: University of Georgia Plant Pathology , University of Georgia, Bugwood.org

Photo Credit: University of Georgia Plant Pathology , University of Georgia, Bugwood.org

Non-chemical management suggestions

The best management practice is to make sure there are no plum trees near the peach trees. This is because plum trees are susceptible to infection and the favorite host of the leafhopper. Also, be sure to dispose of any infected trees.

For more information

https://agrilifeextension.tamu.edu/library/gardening/european-stone-fruit-yellows/

https://www.agrilifebookstore.org/European-Stone-Fruit-Yellows-p/eplp-007.htm

References

https://www.virginiafruit.ento.vt.edu/peachyellows.html

https://www.cabi.org/isc/datasheet/39168

Phony Peach (bacterium – Xylella fastidiosa): This disease does not cause rapid death of trees but results in reduced growth and fruit size. Twigs on diseased trees have shortened internodes and increased lateral branching. The general appearance is a dwarfed, compact growth pattern with dark green foliage. After a few years, the wood becomes brittle and terminal dieback is common. Infected trees leaf out first in the spring and hold their foliage later in the fall. Fruit also ripens earlier on diseased trees. Disease is spread by root grafting and leafhoppers. Remove all trees showing symptoms of phony peach and destroy wild plums growing near the orchard.

Pathogen

Parts of plant affected

Signs & Symptoms

Non-chemical management suggestions

For more information

References

Phytophthora Root Rot (fungus – Phytophthora spp.): Roots infected by this fungus show extensive root necrosis. Although Phytophthora Root Rot has not been verified in Texas, its presence is suspected based on its wide distribution. Phytophthora Root Rot is most severe on replant sites or in orchards planted on poorly drained soils.

Rhizopus Rot (fungus – Rhizopus stolonifer): This fungus is most active during warm, humid weather. Fruit infection results in a “black whiskered” appearance caused by fungal strands which produce an abundance of black spores. Rhizopus attacks peaches and plums only at maturity. Disease prevention is primarily based on orchard sanitation, preharvest fungicides, and rapid refrigeration of processed fruit. Picking containers should be such that fruit receives a minimum amount of handling. Packing equipment should cause minimum injury. Pad any area where fruit will drop onto a belt or roller.

Root Knot (Nematode – Meloidogyne spp.) Use resistant rootstocks. (See Root Knot Nematode)

Peach Rootstock and Their Reaction To Root Knot Nematode

Rootstock Root Knot (Meloidogyne spp.)
Nemaguard Resistant
Lovell Susceptible
Elberta Susceptible
Nemared Resistant (Has not been extensively evaluated in Texas)
Note: Different races exist within root knot species. Some have been shown to attack “resistant rootstocks” under greenhouse conditions.

Rust (fungus – Tranzschelia discolor): Reddish-brown pustules occur on the lower leaf surface marked by a yellow spot on the upper surface (See Photo). It causes premature defoliation which reduces tree vigor. The rust species that infects peach does not infect plum. In most parts of Texas rust is a late season disease that generally does not require treatment. (See Fungicide Table Below)

Shot Hole (fungus – Wilsonomyces carpophilus): Was formerly called Coryneum blight. Blight lesions on leaves are small, circular, purple spots. In advanced stages spots on the leaves fall out giving the leaf a ragged appearance. Defoliation seldom occurs unless infection is severe. Fruit infection is rare. Buds and twigs die if heavily infected. For most effective disease control, apply dormant sprays immediately after leaves are shed or just prior to budbreak in spring. (See Fungicide Table Below)

Waterlogging (physiological): Peach and nectarines, more so than apricots, require well drained soil for good growth. Prolonged periods of waterlogged soil depletes soil oxygen which is deadly to roots. Foliage may turn yellow and shed or develop a reddish purple color. Dead roots are deep purple to black inside and have a foul odor (See Photo). Where needed, terrace land for optimum drainage and plant on raised beds.

Fungicides for use on Prunus species

Bacterial Spot Brown Rot Peach Leaf Curl Scab Shot Hole Rhizopus Rot Rust
copper hydroxide,
ziram,
spreptomycin
sulfate
benomyl, captan,
iprodione, triforine, thiophanate methyl, propiconazole,
fenbuconazole,
tebuconazole, sulfur
chlorothalonil,
copper hydroxide,
ziram
benomyl,
captan,
chlorothalonil, thiophanate
methyl, sulfur, iprodione
chlorothalonil,
copper hydroxide
dicloran chlorothalonil,
sulfur
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