Are peach trees sensitive to air pollution? What are symptoms of air pollution injury?

Answer:
[Note: this answer is based on information published from the following source: Heggestad, H.E. 1976.  Air pollution injuries to stone fruit trees, p. 355-364. In: USDA Agriculture Handbook No. 437, Virus Diseases and Noninfectious Disorders of Stone Fruits in North America].

Although it is fairly uncommon, peach trees can be damaged by air pollution.  There are three primary air pollutants that cause phytotoxicity to peach.  These are fluoride, sulfur dioxide, and ozone.  The primary sources of fluoride include chemical industries that use fluoride, brick and pottery manufacturing facilities, phosphate rock processing sites, and industries that manufacture aluminum and steel.  Leaf symptoms of fluoride injury can range from minor chlorosis to necrosis and are typically dose dependent.  High doses of fluoride can cause defoliation. Symptoms are typically worse during drought or with unfavorable soil conditions.  Fluoride injury to fruit can cause a soft suture.  This typically appears first during the final phase of fruit growth.  At the stylar end of the fruit (near tip), the skin along the suture begins to turn red prematurely.  This tissue then matures more rapidly and becomes soft.  It may crack and is more subject to bruising and decay.  According to the 1976 Ag. Handbook (noted above), “soft suture of peach can be controlled by one to three sprays of lime or calcium chloride (i.e., two pounds of calcium chloride per 100 gallons of water) applied at 2- to 3-week intervals, beginning at pit hardening”.  The primary sources of sulfur dioxide include the manufacturing of sulfur and sulfuric acid, production and refining of petroleum and natural gas, ore smelting and the burning of fossil fuels.  Leaf symptoms include spotting that results from death of cells in interveinal areas.   Ozone is typically associated with smog.  Symptoms often include flecking or stippling on the upper leaf surface.  The symptom can be confused with injury from mites.  At higher doses, dark lesions and shotholing can result.  Some researchers utilized ozone as a postharvest treatment to reduce fruit decay.  Injury symptoms were described as “sunken and browned tissue in the region of the stomata”.  The fruit had a “pebbly” appearance.

Chlorosis of peach leaves resulting from fluoride toxicity

Chlorosis of peach leaves resulting from fluoride toxicity (Source: Heggestad, H.E. 1976.  Air pollution injuries to stone fruit trees, p. 355-364. In: USDA Agriculture Handbook No. 437, Virus Diseases and Noninfectious Disorders of Stone Fruits in North America).

Necrosis of peach leaves resulting from fluoride toxicity

Necrosis of peach leaves resulting from fluoride toxicity (Source: Heggestad, H.E. 1976.  Air pollution injuries to stone fruit trees, p. 355-364. In: USDA Agriculture Handbook No. 437, Virus Diseases and Noninfectious Disorders of Stone Fruits in North America).

Soft suture of peach fruit resulting from fluoride toxicity.

Soft suture of peach fruit resulting from fluoride toxicity. (Source: Heggestad, H.E. 1976.  Air pollution injuries to stone fruit trees, p. 355-364. In: USDA Agriculture Handbook No. 437, Virus Diseases and Noninfectious Disorders of Stone Fruits in North America).

Leaves of peach

Leaves of peach, left, and apricot, right, injured by exposure to sulfur dioxide 3 ppm for 4 hours. (Source: Heggestad, H.E. 1976.  Air pollution injuries to stone fruit trees, p. 355-364. In: USDA Agriculture Handbook No. 437, Virus Diseases and Noninfectious Disorders of Stone Fruits in North America).

Peach leaves showing chlorosis and dark lesions with shotholing resulting from ozone toxicity

Peach leaves showing chlorosis and dark lesions with shotholing resulting from ozone toxicity; normal leaf on left. (Source: Heggestad, H.E. 1976.  Air pollution injuries to stone fruit trees, p. 355-364. In: USDA Agriculture Handbook No. 437, Virus Diseases and Noninfectious Disorders of Stone Fruits in North America).

Peach fruit showing pebbly appearance on right due to ozone damage; normal fruit on left.

Peach fruit showing pebbly appearance on right due to ozone damage; normal fruit on left. (Source: Heggestad, H.E. 1976.  Air pollution injuries to stone fruit trees, p. 355-364. In: USDA Agriculture Handbook No. 437, Virus Diseases and Noninfectious Disorders of Stone Fruits in North America).

 

Learn more: 

Back to the list of questionsgreen go button, back to the FAQ home page
Return home...

everything about peaches, desmond layne, clemson university