| Scientific Name | Peronospora destructor (Berk.) Casp. ex Berk. Outl. Brit. Fung. (London): 349 (1860) |
|---|---|
| Synonyms | 2 synonymsBotrytis destructor Berk., Ann. Mag. Nat. Hist., Ser. 1, 6: 436 (1841)
Peronospora schleidenii Unger, Bot. Ztg. 5: 315 (1847) |
| Disease | Downy mildew |
| Taxonomic Rank | |||
|---|---|---|---|
| Order | Peronosporales | Family | Peronosporaceae |
| Host Plant | |||
|---|---|---|---|
| Common Name | Onion (양파) | Scientific Name | Allium cepa |
| Common Name | Welsh onion (파) | Scientific Name | Allium fistulosum |
| Distribution | Circumglobal where the host plant is growing |
|---|---|
| Characteristics | Lesions commonly present on leaves as yellow to light-green spots of variable size, later becoming darker; infected leaves become stunted, shriveled, collapse, and eventually die. Down greyish violet owing to the color of the conidia, consisting of scattered to agglomerated conidiophores. Conidiophores hyaline to subhyaline, stout, straight, (217.4–)252.1–280.0–307.9(–353.2) µm long, 20–30 µm below the first branch; trunk straight, (99.8–)125.9–148.0–170.1(–195.7) µm long, basal end not differentiated, rarely slightly bulbous, (7.7–)9.4–11.5–13.6(–16.2) µm wide at the base, callose plugs absent; branches simple, monopodially or trichotomously branched in 3–5(–6) orders. Ultimate branchlets paired or single, substraight to slightly curved, (6.5–)8.4–12.4–16.3(–22.3) µm long, (2.7–)3.2–3.9–4.6(–5.1) µm wide at the base, apex subtruncate or rarely obtuse. Conidia pale brown to brown, obovoid to pyriform, (41.7–)54.6–61.2–67.8(–72.6) µm long, (22.0–)24.3–26.8–29.3(–32.7) µm wide, l/w ratio (1.79–)2.04–2.29–2.54(–2.87) (n = 30), greatest width median or supra-median, becoming narrower toward the base; pedicel slightly protruding, up to 3 µm wide and 1.5 µm long. Resting organs not observed. |
| Notes | Notes Peronospora destructor is an obligate biotrophic oomycete causing downy mildew primarily on Allium cepa. It is widely distributed in onion-growing regions worldwide and has also been reported from several other cultivated Allium species, including A. fistulosum, A. porrum, A. schoenoprasum, and A. tuberosum (Thines and Choi 2016). The pathogen is morphologically characterized by relatively large, pigmented, obovoid to pyriform conidia and ultimate branchlets with predominantly subtruncate apices. Conidiophore length varies considerably among collections and is therefore less useful as a diagnostic character than conidial morphology and the shape of the ultimate branchlets. In Korea, downy mildew caused by P. destructor was recorded on both A. cepa and A. fistulosum as early as 1928 (Nakata et al. 1928). The disease on A. cepa was subsequently reported by Park (1958) and Chung (1964), confirming its continued occurrence in Korea. Additional records on A. cepa and A. fistulosum have since been documented in Korean disease surveys and monographs. |
| Economic importance | Downy mildew caused by Peronospora destructor is one of the most destructive diseases of onion worldwide and can cause substantial losses in bulb and seed production. Disease development is strongly favored by cool, humid conditions and prolonged leaf wetness, which promote sporulation, infection, and secondary spread (Van der Heyden et al. 2020). Severe infection causes progressive chlorosis, leaf collapse, and premature death of foliage, resulting in reduced bulb development and marketable yield. In Korea, P. destructor has long been associated with downy mildew of A. cepa and A. fistulosum. The disease was recorded as early as 1928 (Nakata et al. 1928), followed by additional reports on onion by Park (1958) and Chung (1964). Because disease outbreaks are strongly influenced by environmental conditions, timely monitoring and integrated management remain important for reducing losses in onion production. |
| References | Nakata, K., et al. 1928. Bull. Chosen Agric. Exp. Stn. 15:86. Park, J. S. 1958. Res. Rep. Coll. Agric. Chungnam Natl. Univ. 1:88. Chung, B. J. 1964. Korean J. Plant Prot. 3:11. Thines, M., and Choi, Y.-J. 2016. Phytopathology 106:6. Van der Heyden, H., et al. 2020. Agronomy 10:738. |
CTCGTTAATCCATTCATGCGCGTCACTAATTAGATGACGAGGCATTTGGCTACCTTAAGAGAGTCATAGTTACTCCCGCCGTTTACCCGCGCTTGGTTGA ATTTCTTCACTTTGACATTCAGAGCACTGGGCAGAAATCACATTGTGTCAACACCATTTTCTGGCCATCACAATGCTATGTTTTAATTAGACAGTCAGAT TCCCCTTGTCCGTTCCAGTTCATAGTTGACAGTTAATTGCTTGCCAGACGCTTTTAAAGGCTGCCCAAAACATCACAATAAAGTTCCATCCAAGTCCGCC ACTAGTTTCCTAGTAGTAGTCCTAGTCAGATCCTTAAAGATCTATTAAGGGCCCAACAAGCCCTGCCCTATGAGCCAATCCTTTTCCCTAAGTTACGGAT CTATTTTGCCGACTTCCCTTATCTACATTATTCTATTGACCAGAGGCTGATCACCTTGGGGACCTGATGCGGATATTGGTACAGTTGGGTACAAGACTTT TTCAATCCCTTGGTTTTTCAAGGATCCTCAAGGACACACCAGACTTTACAGAGGTGTAAAGCTCTACCAATCATTAAACCCTATCTCCAAATAATTTGCT TCCAGGGTTTCAGATTGTTAAGGAGAAAAGAAAACTCTTCCTGGGGCCCTTGCAGATGTCACCAAGTTCATATATGTTACCATTCAAAATCTGTATCCCA GTTGTAGAATTTTAACTACATTCCCTTTCAATAGGTGATGCTAACAAGAGCATACTTTAAAACAGACTTTCCCTATCTTTTAGGACTGACTAACCCATGT CCAACTACTGTGACCATGGAACCCTTCCCCACTTCAGTCTTCAAGGTTCTCACTTGAATATTTGCTACTTCCACCAAGATCTGCACTAGAGGCTGTTTCA CTCAGCATCACTGCTAAAGCTTCAATACAAAACCCCCACGCCTGCCTACTCATTAATATTTTAAATAATATTAATGGCAAGGTATAGGTAATACACTTAA GCGCCATCCATTTTCAGGGCTAGTTCATTCGGCCGTTGAGTTGTTACACACTCCTTAGCGGATTCCGACTTCCATGGCCACCGTGCGGCTGTCTAGATGA ACTAACACCTTTTGTGGTGTCTCATGAGTGTATATTCTGGCACCTTAACCTTGCGTTCGGTTCATCCCGCATCGCCAGTTCTGCTTACCAAAAATGGCCC ACTAGAGACTCTCATTCAAATTCCCAAGTTCAATTAAGAAACAGGGGTATCTTACATATTTAAAGTTTGAGAATAGGTTAAGGATGTTTCATCCCCAAGG CCTCTAATCATTCGCTTTACCTCATAAAACTGATGTGAGTCTCTGCTATCCTGAGGGAAACTTCGGCAGGAACCAGCTACTAGATGGTTCGATTAGTCTT TCGCCCCTATACCCAAATTTGACAATCGATTTGCACGTCAGAACTGCTACGAGCTTCCACCAGAGTTTCCTCTGGCTTCACCCTATTCAGGCATAGTTCA CCATCTTTCGGGTCCCAACATACTTGCTCTTACTCAGTACCATCATATAAATAATCTGGACTGGTCAATGGTGCACTTTTTACAGATCCCATTTACATTC ACTTTCATTACGCATAAGGGTTTTAACACCCAAATACTCGCAAGCATGTTAGACTCCTTGGTCCGTGTTTCAAGACGGGTCATTTAAAGCTATTATACCA ACATCCTCAATAAGAAAAACATTAATTTGTTTTACCAAATAAATGGCTTATTGCGATCCTCAATCTTAAACATTGTATCAAATTTAAGGATTATAACACA GCCTAAACTGTAACATCTCCAAAAACCTTCTCCAACATTCAAAGATTGATGTTGGTCTGTTAATCATTAGAATACACCTTTAAAAAAGTTGAACTAACAA TAACAAGTCTAACTTCAAATGTTTCCCTTTTAACAATTTCACGTACTGTTAACTCTCTTTCCAAAGTTCTTTTCATCTTTCCCTCACGGTACTTGTTTGC TATCGGTCTCTCACCTATATTTAGCCTTAGATGGAATTTACCACCCACTTTGAGCTGCATTCCCAAACAACTCGACTCTTAGAGACTGTATCATATAGTA CTACTTATCCATTCCATAAACGGGATTATCACCCTCAATGATGCTGTTTTCCAACAGACTTATAAATGGGGTAGCACAGAAAACAGCTCTTCAAATTACA ACTCGGACTCTAAAAGAGCCAGATTACAAATTTGGGCTTTTCCCTCTTCACTCGCCGTTACTAGGGGAATCCTTGTTAGTTTCTTTTCCTCTGCTTATTG ATATGCTTAAGTTCAGCAGGTAGTCCCACCTGATTTGAGGTCTTAAAAAAAGAATTTGTCATATTGACAGGTTAGAAGCAATTTCATTACTATAAAGAAA TGGCAGTATCTAAAAAAGATACACTTCTTAATGAAGATAATATATCACATTAAGTCAATCCAAATCAAAGTATGAAAAAAACTTATATATTTAAAGTGAG CCAATTACAGCAACACTCAAAATCCATTAAAAAATCTTAATAAAATAAAATTAATTAATGAGAAGGTTTCATGACACTCAAACAGGTGTGCCTTTTGGAA TACCAAAAGGCGCAAGGTGCGTTCAAAGATTCGATGATTCACTGAATTCTGCAATTCACATTACTTATCACATTTCACTGTGTTCTTCATCGATGTGAGA GCCTAGAGATCCATTGTTAAAAGTTATATAATTTTTTGGTTTTTACATTCTTAAAACTTGATTTTAGACAATAATAATAAGGGGGGTAATGTGACAAAGA TTAATATCTTTGCCACGTATACCAAATTACTATGTTTCAATAAAGCTACATGTAATAAGGTAGAAGTTGTTTAAATTTTAAAAATTTGAGCCACAATTAA GTGCACTCATTTTTTTAATAATGATCCTTCCGCAGGTTCACCTACGGAAACCTTGTTACGACTTTTACTTC | | | | | | | | | | | 1 10 20 30 40 50 60 70 80 90 100
CTCGTTAATCCATTCATGCGCGTCACTAATTAGATGACGAGGCATTTGGCTACCTTAAGAGAGTCATAGTTACTCCCGCCGTTTACCCGCGCTTGGTTGA ATTTCTTCACTTTGACATTCAGAGCACTGGGCAGAAATCACATTGTGTCAACACCATTTTCTGGCCATCACAATGCTATGTTTTAATTAGACAGTCAGAT TCCCCTTGTCCGTTCCAGTTCATAGTTGACAGTTAATTGCTTGCCAGACGCTTTTAAAGGCTGCCCAAAACATCACAATAAAGTTCCATCCAAGTCCGCC ACTAGTTTCCTAGTAGTAGTCCTAGTCAGATCCTTAAAGATCTATTAAGGGCCCAACAAGCCCTGCCCTATGAGCCAATCCTTTTCCCTAAGTTACGGAT CTATTTTGCCGACTTCCCTTATCTACATTATTCTATTGACCAGAGGCTGATCACCTTGGGGACCTGATGCGGATATTGGTACAGTTGGGTACAAGACTTT TTCAATCCCTTGGTTTTTCAAGGATCCTCAAGGACACACCAGACTTTACAGAGGTGTAAAGCTCTACCAATCATTAAACCCTATCTCCAAATAATTTGCT TCCAGGGTTTCAGATTGTTAAGGAGAAAAGAAAACTCTTCCTGGGGCCCTTGCAGATGTCACCAAGTTCATATATGTTACCATTCAAAATCTGTATCCCA GTTGTAGAATTTTAACTACATTCCCTTTCAATAGGTGATGCTAACAAGAGCATACTTTAAAACAGACTTTCCCTATCTTTTAGGACTGACTAACCCATGT CCAACTACTGTGACCATGGAACCCTTCCCCACTTCAGTCTTCAAGGTTCTCACTTGAATATTTGCTACTTCCACCAAGATCTGCACTAGAGGCTGTTTCA CTCAGCATCACTGCTAAAGCTTCAATACAAAACCCCCACGCCTGCCTACTCATTAATATTTTAAATAATATTAATGGCAAGGTATAGGTAATACACTTAA GCGCCATCCATTTTCAGGGCTAGTTCATTCGGCCGTTGAGTTGTTACACACTCCTTAGCGGATTCCGACTTCCATGGCCACCGTGCGGCTGTCTAGATGA ACTAACACCTTTTGTGGTGTCTCATGAGTGTATATTCTGGCACCTTAACCTTGCGTTCGGTTCATCCCGCATCGCCAGTTCTGCTTACCAAAAATGGCCC ACTAGAGACTCTCATTCAAATTCCCAAGTTCAATTAAGAAACAGGGGTATCTTACATATTTAAAGTTTGAGAATAGGTTAAGGATGTTTCATCCCCAAGG CCTCTAATCATTCGCTTTACCTCATAAAACTGATGTGAGTCTCTGCTATCCTGAGGGAAACTTCGGCAGGAACCAGCTACTAGATGGTTCGATTAGTCTT TCGCCCCTATACCCAAATTTGACAATCGATTTGCACGTCAGAACTGCTACGAGCTTCCACCAGAGTTTCCTCTGGCTTCACCCTATTCAGGCATAGTTCA CCATCTTTCGGGTCCCAACATACTTGCTCTTACTCAGTACCATCATATAAATAATCTGGACTGGTCAATGGTGCACTTTTTACAGATCCCATTTACATTC ACTTTCATTACGCATAAGGGTTTTAACACCCAAATACTCGCAAGCATGTTAGACTCCTTGGTCCGTGTTTCAAGACGGGTCATTTAAAGCTATTATACCA ACATCCTCAATAAGAAAAACATTAATTTGTTTTACCAAATAAATGGCTTATTGCGATCCTCAATCTTAAACATTGTATCAAATTTAAGGATTATAACACA GCCTAAACTGTAACATCTCCAAAAACCTTCTCCAACATTCAAAGATTGATGTTGGTCTGTTAATCATTAGAATACACCTTTAAAAAAGTTGAACTAACAA TAACAAGTCTAACTTCAAATGTTTCCCTTTTAACAATTTCACGTACTGTTAACTCTCTTTCCAAAGTTCTTTTCATCTTTCCCTCACGGTACTTGTTTGC TATCGGTCTCTCACCTATATTTAGCCTTAGATGGAATTTACCACCCACTTTGAGCTGCATTCCCAAACAACTCGACTCTTAGAGACTGTATCATATAGTA CTACTTATCCATTCCATAAACGGGATTATCACCCTCAATGATGCTGTTTTCCAACAGACTTATAAATGGGGTAGCACAGAAAACAGCTCTTCAAATTACA ACTCGGACTCTAAAAGAGCCAGATTACAAATTTGGGCTTTTCCCTCTTCACTCGCCGTTACTAGGGGAATCCTTGTTAGTTTCTTTTCCTCTGCTTATTG ATATGCTTAAGTTCAGCAGGTAGTCCCACCTGATTTGAGGTCTTAAAAAAAGAATTTGTCATATTGACAGGTTAGAAGCAATTTCATTACTATAAAGAAA TGGCAGTATCTAAAAAAGATACACTTCTTAATGAAGATAATATATCACATTAAGTCAATCCAAATCAAAGTATGAAAAAAACTTATATATTTAAAGTGAG CCAATTACAGCAACACTCAAAATCCATTAAAAAATCTTAATAAAATAAAATTAATTAATGAGAAGGTTTCATGACACTCAAACAGGTGTGCCTTTTGGAA TACCAAAAGGCGCAAGGTGCGTTCAAAGATTCGATGATTCACTGAATTCTGCAATTCACATTACTTATCACATTTCACTGTGTTCTTCATCGATGTGAGA GCCTAGAGATCCATTGTTAAAAGTTATATAATTTTTTGGTTTTTACATTCTTAAAACTTGATTTTAGACAATAATAATAAGGGGGGTAATGTGACAAAGA TTAATATCTTTGCCACGTATACCAAATTACTATGTTTCAATAAAGCTACATGTAATAAGGTAGAAGTTGTTTAAATTTTAAAAATTTGAGCCACAATTAA GTGCACTCATTTTTTTAATAATGATCCTTCCGCAGGTTCACCTACGGAAACCTTGTTACGACTTTTACTTC | | | | | | | | | | | 1 10 20 30 40 50 60 70 80 90 100
