Pleospora herbarum
leaf blight of onion
Too many to list, most commonly used names include Alternaria putrefaciens, Clasterosporium putrefaciens, Sporidesmium putrefaciens, Stemphyllium botryosum, Stemphylium herbarum.
Worldwide
Widespread
2023-08-21
fungus
Wide host range
PLEOHE
Primarily a post harvest pathogen
17 Known Hosts
Allium cepa
onion
No
PLEOHE-2, PLEOHE-4
Pathway not proven. Some references indicate an association of Stemphylium botryosum spores with seed, however, no references found to indicate that seed is a proven pathway in onion.
Beta vulgaris
table beet, swiss chard
No
No references found indicating that seed is a pathway
Brassica oleracea vars.
broccoli, cabbage, cauliflower, brussel sprouts
No
No references found indicating seed is a pathway
Cucumis melo
melon
No
No references found indicating seed is a pathway
Cucurbita spp.
squash, pumpkin, gourd
No
No references found indicating seed is a pathway
Glycine max
soybean
No
No references found indicating that seed is a pathway
Hordeum vulgare
barley
No
No references found indicating seed is a pathway
Medicago sativa
alfalfa
No
PLEOHE-6, PLEOHE-7, PLEOHE-16
Pathway not proven. All three references only show that the pathogen can infect seed and recovered later in laboratory assays. No data on seed transmission found or seed being a pathway in nature. Infected seed is usually smaller than healthy.
Yes
Blotter assay, Grow out
Standard blotter or freezing blotter are methods used by ISTA. No evidence of seed transmission.
Freezing blotter incubation
PLEOHE-15
Conditioning seed for removal of small sizes may help reduce seed lot contamination
Al-Askar AAA, Ghoneem KM, Rashad YM, 2012. Seed-borne mycoflora of alfalfa (Medicago sativa L.) in the Riyadh region of Saudi Arabia. Annals of Microbiology, 62:273-281
Susuri LR, Doda-Gashi N, 2003. Alfalfa seed microflora and some characteristics of obtained isolates. (Mikroflora sjemena lucerne i neke karakteristike dobiveneh izolata.) Fragmenta Phytomedica et Herbologica, 28:81-88.
Neslon, RR, 1955. Stemphyllium Leafspot on Alfalfa. Phytopathology 45:352-356
International Seed Testing Association (1999) International rules for seed testing. Seed Sci Technol 24:1–35
Oryza sativa
rice
No
No references found indicating seed is a pathway
Phaseolus vulgaris
common bean
No
PLEOHE-11
Reference above cites one publication from 1938, but this reference discussed techniques for detection. No other references found indicating seed is a pathway.
Richardson, MJ, 1990. An Annotated List of Seedborne Diseases. International Seed Testing Association, Zurich, Switzerland
Pisum sativum
pea
Yes
PLEOHE-9, PLEOHE-10
There are a few reports of this pathogen being associated with seed, however, the importance of seedborne inoculum is unknown or relatively unimportant.
No
Raphanus sativus
radish
No
No references found indicating seed is a pathway
Solanum lycopersicum
tomato
No
PLEOHE-11
Pathway not proven. Reference above cited unpublished research that cannot be verified. No other references found indicating seed is a pathway.
Richardson, MJ, 1990. An Annotated List of Seedborne Diseases. International Seed Testing Association, Zurich, Switzerland
Sorghum bicolor
sorghum
No
No references found indicating seed is a pathway
Spinacia oleracea
spinach
Yes
PLEOHE-3, PLEOHE-4
Seed is a known pathway in spinach.
Yes
Freezing blotter incubation
Freezing blotter incubation is the standard method of the NSHS
PLEOHE-3, PLEOHE-5
Fungicide seed treatments
PLEOHE-2, PLEOHE-4, PLEOHE-3
du Toit L, Hernandez-Perez P, 2005. Efficacy of hot water and chlorine for eradication of Cladosporium variabile, Stemphylium botryosum, and Verticillium dahliae from spinach seed. Plant Disease, 89:1305-1312.
International Seed Federation Regulated Pest List Database. www.pestlist.worldseed.org. Nyon, switzerland
Seed Health Testing Method for Stemphylium botryosum fsp spinacia Lcb 6.1 National Seed Health System, 2017. www.seedhealth.org
Barnwal MK, Prasad SM, Maiti D, 2003. Efficacy of fungicides and bioagents against Stemphylium blight of onion. Indian Phytopathology, 56(3):291-292.
Triticum aestivum
wheat
No
No references found indicating seed is a pathway.
Zea mays
corn
No
No references found indicating seed is a pathway
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