Powdery mildew
Powdery mildew | |
---|---|
Causal agents | Species of fungi in the order Erysiphales |
Hosts | plants |
Powdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant diseases to identify, as the signs of the causal pathogen are quite distinctive. Infected plants display white powdery spots on the leaves and stems.[1] This mycelial layer may quickly spread to cover all of the leaves. The lower leaves are the most affected, but the mildew can appear on any above-ground part of the plant. As the disease progresses, the spots get larger and denser as large numbers of asexual spores are formed, and the mildew may spread up and down the length of the plant.
Powdery mildew grows well in environments with high humidity and moderate temperatures; greenhouses provide an ideal moist, temperate environment for the spread of the disease. This causes harm to agricultural and horticultural practices where powdery mildew may thrive in a greenhouse setting.[2] In an agricultural or horticultural setting, the pathogen can be controlled using chemical methods, bio-organic methods, and genetic resistance. It is important to be aware of powdery mildew and its management strategies as the resulting disease can significantly reduce important crop yields.[3]
Reproduction
Powdery mildew fungi reproduce both sexually and asexually.
Under optimal conditions,
Vectors of transmission
Powdery mildew does not need a vector to spread. Spores are usually carried by air currents from a proliferation site to a new infection site.[citation needed]
DNA repair
DNA mismatch repair (MMR) is an enzymatic system for recognizing and repairing erroneous base insertions, deletions, and mis-incorporations in DNA that can arise during DNA replication and recombination.[8] This system can also repair some forms of DNA damage. Four closely related species of plant parasites from the powdery mildew genera were found to have lost between 5 and 21 of the 48 to 52 MMR genes that are present in most other ascomycete genomes.[9] The powdery mildew species with higher levels of MMR gene loss exhibited elevated rates of various types of mutation.[9] These elevated mutation rates suggest that a lack of genes essential for accurate DNA replication can cause an increased rate of sequence evolution and evolutionary diversification.[9]
Management
In an agricultural setting, the pathogen can be controlled using chemical methods, genetic resistance, and careful farming methods.[citation needed]
Prevention
You can look for powdery mildew resistant varieties in seed catalogs and alternate between resistance varieties and not. This rotation of sunflower varieties promotes pathogen resistance.[citation needed]
Reduce humidity by allowing space between plants for airflow and pruning to thin foliage.[7]
Conventional chemical control
Standard fungicides are an effective way to manage powdery mildew disease on plants.[10] Spray programs of conventional fungicides are advised to begin when powdery mildew symptoms and signs are first noticed.[11] Conventional fungicides should be applied on a regular basis for best results against the disease.[11]
Control is possible with triadimefon and propiconazole. It is also possible with hexaconazole, myclobutanil, and penconazole.[10]
Non-conventional chemical control
There are some unconventional chemical control methods that offer alternative modes of action.[2]
The most effective non-conventional methods of chemical control against powdery mildew are milk, natural sulfur (S8), potassium bicarbonate, metal salts, and oils.[12]
Metal salt fungicides should be applied on a regular basis up until harvest of the host.[12] Sulfur must be applied before the disease has emerged since it prevents fungi spores from germinating.[13] Copper sulfate is an effective fungicide allowed in organic farming, but can cause harm to the host plant. Addition of lime hampers this effect.[13]
Neem oil effectively manages powdery mildew on many plants by interfering with the fungus' metabolism and terminating spore production.[13] Sulfur and Fish Oil + Sesame Oil is a mixture effective against powdery mildew.[2]
Dilute sprays containing sodium bicarbonate (baking soda) and vegetable or mineral oils in water are often recommended for controlling powdery mildew, but such mixtures have limited and inconsistent efficacy.[17] While sodium bicarbonate has been shown to reduce to growth of mildews in lab tests, sprays containing only baking soda and water are not effective in controlling fungal diseases on infected plants, and high concentrations of sodium are harmful to plants.[17]
Potassium bicarbonate is an effective low-toxicity fungicide against powdery mildew and apple scab.[18][19][20][21]
Another non-conventional chemical treatment involves treating with a solution of
Genetic resistance
The Pm3 allele is an effective genetic resistance strategy that protects host species against powdery mildew fungus.[23]
Gene editing
In 2014, researchers Yanpeng Wang et al. have reported that they were able to induce resistance in
Powdery mildews of various plants
Sunflowers
Sunflower powdery mildew is a disease caused by the pathogens
Wheat, barley and other cereals
Legumes
Legumes, such as soybeans, are affected by Microsphaera diffusa.[26]
Grape
Erysiphe necator (or Uncinula necator) causes powdery mildew of grapes.[citation needed]
Onions
The fungus causing powdery mildew of onions is Leveillula taurica (also known by its anamorph name, Oidiopsis taurica). It also infects the artichoke.
Apples and pears
Podosphaera leucotricha is a fungus that can cause powdery mildew of apples and pears.[citation needed]
Gourds and melons
Multiple species of
.Since 1925, commercial
A 2004
At least three other
Lilacs
Strawberries
Podosphaera aphanis is the cause of powdery mildew in strawberries and other Rosaceae like Geum rivale (the water avens).[citation needed]
Tree leaves
Sawadaea tulasnei is a fungus that causes powdery mildew on tree leaves. This fungus attacks the leaves of the Acer platanoides (Norway maple) in North America, Great Britain, and Ireland, Acer palmatum (also known as the Japanese maple or smooth Japanese maple).[34]
Oregon grape
Arabidopsis
Golovinomyces orontii causes powdery mildew on Arabidopsis (rockcress) leaves.[citation needed]
Cannabis
Caused by several fungi including Golovinomyces ambrosiae (syn. G. spadiceus) and Podosphaera macularis.[36]
Hyperparasites of powdery mildew
In the family Sphaeropsidaceae of the Sphaeropsidales fungi, species of the genus Cicinnobolus are hyperparasites of powdery mildew.[37]
See also
References
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- ^ ISSN 0261-2194.
- ^ "Small Grain Wheat Diseases - Powdery Mildew". Archived from the original on 2002-12-23.
- ^ a b "Sexual reproduction only second choice for powdery mildew". Science Daily. July 14, 2013. Archived from the original on 2013-08-21.
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- ^ a b Grabowski, Michelle. "Powdery Mildew in the Flower Garden".
- ^ Iyer RR, Pluciennik A, Burdett V, Modrich PL (February 2006). "DNA mismatch repair: functions and mechanisms". Chemical Reviews. 106 (2): 302–23. doi:10.1021/cr0404794. PMID 16464007
- ^ a b c Phillips MA, Steenwyk JL, Shen XX, Rokas A. Examination of Gene Loss in the DNA Mismatch Repair Pathway and Its Mutational Consequences in a Fungal Phylum. Genome Biol Evol. 2021 Oct 1;13(10):evab219. doi: 10.1093/gbe/evab219. PMID 34554246; PMCID: PMC8597960
- ^ a b "CHEMICAL CONTROL OF POWDERY MILDEW OF APPLE IN WARMER CLIMATES OF HIMACHAL PRADESH, INDIA". Actahort.org. Retrieved 2018-04-24.
- ^ a b Petterson, James. "Measure for Control". Projects.ncsu.edu. Archived from the original on 2019-10-01. Retrieved 2018-04-24.
- ^ a b "Powdery Mildew: Symptoms, Treatment and Control | Planet Natural". Planet Natural. Retrieved 2018-04-24.
- ^ a b c Beckerman, Janna. "Using Organic Fungicides" (PDF). Disease Management Strategies for Horticultural Crops.
- ^ a b DeBacco, Matthew. "Compost Tea and Milk to Suppress Powdery Mildew (Podosphaera xanthii) on Pumpkins and Evaluation of Horticultural Pots Made from Recyclable Fibers Under Field Conditions". University of Connecticut. Retrieved 5 May 2013.
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- ^ a b c Raloff, Janet. "A Dairy Solution to Mildew Woes". Science News Magazine. Retrieved 5 May 2013.
- ^ a b Chalker-Scott, Linda. "Miracle, myth...or marketing? Baking soda: will fungi fail and roses rejoice?" (PDF). Puyallup Research and Extension Center. Washington State University. Retrieved 12 August 2017.
- ^ "Use of Baking Soda as a Fungicide - Publication Summary - ATTRA - National Sustainable Agriculture Information Service". Attra.ncat.org. Archived from the original on 7 May 2010. Retrieved 9 June 2018.
- ^ Powdery Mildew – Sustainable Gardening Australia Archived 2016-03-03 at the Wayback Machine.
- ^ Organic Fruit Production in Michigan Archived 2012-02-16 at the Wayback Machine.
- ^ Tamm, Lucius; Amsler, Thomas; Schaerer, Hansjakob; Refardt, Mathias (2006). "Efficacy of Armicarb (potassium bicarbonate) against scab and sooty blotch on apples" (PDF). In Boos, Markus (ed.). Ecofruit: 12th International Conference on Cultivation Technique and Phytopathological Problems in Organic Fruit-growing. pp. 87–92. Retrieved 10 August 2015.
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- ^ "Combination of resistance genes offers better protection for wheat against powdery mildew". Retrieved 2018-04-24.
- ^ Wang et al. Simultaneous editing of three homoeoalleles in hexaploid bread wheat confers heritable resistance to powdery mildew. Nature Biotechnology 2014.
- ^ Harveson, Robert M (2016). Compendium of Sunflower Diseases and Pests. APS Press.
- ^ Bennett, J. Michael; Rhetoric, Emeritus; Hicks, Dale R.; Naeve, Seth L.; Bennett, Nancy Bush (2014). The Minnesota Soybean Field Book (PDF). St Paul, MN: University of Minnesota Extension. p. 85. Archived from the original (PDF) on 30 September 2013. Retrieved 21 February 2016.
- ^ a b c "Powdery Mildew of Cucurbits fact sheet". Vegetablemdonline.ppath.cornell.edu. Retrieved 9 June 2018.
- ^ a b "Watermelon Breeding (by year, then author) - Cucurbit Breeding". Cucurbitbreeding.com. Retrieved 9 June 2018.
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- ^ Velkov, Nikolay; Masheva, Stoika (2002). "Species and Races Composition of Powerdy Mildew on Cucurbits in Bulgaria" (PDF). Cucurbit Genetics Cooperative Report. 25: 7–10. Retrieved 10 August 2015.
- ^ "Problem: Powdery Mildew of Lilac (Microsphaera syringae)". Archived from the original on 2011-07-19. Retrieved 2010-08-03.
- ^ "Sawadaea tulasnei - Overview - Encyclopedia of Life". Encyclopedia of Life. Retrieved 9 June 2018.
- ^ "Pacific Northwest Plant Disease Management Handbook". Pnwhandbooks.org. Archived from the original on 2016-08-16. Retrieved 9 June 2018.
- ^ Ocamb, Cynthia M. (2015-09-11). "Hemp (Cannabis sativa)-Powdery Mildew". Pacific Northwest Pest Management Handbooks. Pacific Northwest Extension (Oregon, Washington, Idaho). Retrieved 2022-05-15.
- ^ faculty.ucr.edu, retrieved December 2015.
- ^ Franceschini, Sergio. "Regulatory information: Ampelomyces quisqualis – AQ 10" (PDF). Archived from the original (PDF) on 2011-07-19. Retrieved 2010-12-12.
- ^ Powdery mildew in the Pesticide Properties DataBase (PPDB)