Allergen Update
Winnipeg, Manitoba
Predominant pollen:
Due to extreme variations in the weather at this site, the tree pollen season fluctuates significantly from year to year. The pollen seasons described here try to cover the time when each can occur.
Acer sp.- Maple season varies due to the effect of weather. Significant counts can be observed from mid-April to late May with some moderate and high counts. The season can start from early to late April and end from early May to early June.
Alnus sp.- Alder season can begin from the end of March to mid or late April, depending on the weather. The season can end between early to mid-June. The counts fluctuate from low to moderate throughout the season. This is due to the number of species present and the effect of weather.
Betula sp.- The birch season can vary by as much as a month from year to year. It can start between late April to late May and can end late May to mid-June. Low to high counts are observed. Birch look-a-likes'season lasts almost one month and occurs mostly during the month of May.
Corylus sp.- The hazelnuts have a season lasting approximately two to three weeks and moderate counts are observed. Pollination can occur from early April to mid-May.
Populus sp.- The Poplar and aspen season can start late March to late April and end early to late May . The counts can get high and may cause allergic reactions.
Fraxinus sp.- The ash pollination season can begin from mid-April to mid-May and end mid-May to mid-June. The season can fluctuate by a month depending on the weather. Some of the counts are high and may cause allergic reactions in highly sensitized individuals.
Pinaceae- Very high counts are observed at this site. The season can start early to late May and can end late June to late July. This group is very important to those who are sensitized.
Cupressaceae group- The cedars, junipers and yews' season is very sporadic with moderate and high counts occuring from late March to late May. The season fluctuates due to the effect of weather. Probably of no significance in causing allergic reactions.
Quercus sp.- The oaks have a short pollinating season occuring between mid-April to early May. The main season, with the highest counts, can start early to late May and and end from late May to mid-June. Oaks are highly allergenic.
Ulmus sp.- The elm are important allergens. The season for elm fluctuates a lot. This has to do with the winter and spring temperatures as well as the number of species present. The season can start late March to early May and end from early May to late May.
Salix- The willows' pollen season can begin mid-April to early May and end late May to early June. The counts are in the low to moderate ranges. The start of the season can be delayed due to the effect of cold weather. May not cause allergic reactions except in highly sensitized individuals.
Gramineae- The grasses produce moderate and high counts from the end of May to the end of July. The season is from mid-May to late September.
Ambrosia sp.- Ragweed pollen season is from mid-July to mid-October with moderate and high counts occurring from August to mid-September.
Urticaceae sp.- Nettles occur in significant numbers that may cause allergic reactions. The season is late June until the end of August with moderate and high counts.
Artemisia sp.- The sagebrushes and mugworts can cause allergic reactions. The season is from late July to late September with some moderate counts occuring from August to mid-September.
Chenopodiaceae & Amaranthaceae- This group of weeds are similar microscopically and are not differentiated. They include some weeds which are considered allergenic. Moderate counts are observed from August to mid-September. The season lasts from late June to early October.
Plantago sp.- The plantains can play an important role in allergic reactions, even at low levels. The counts are only in the low ranges from late June until mid-September.
Predominant spores:
Diatrypaceae sp.- The counts are sporadic with high counts throughout the counting season. The season is from late March to mid-October.
Leptosphaeria sp. & Leptosphaeria look-a-likes- These two are grouped together since they are in the same class of fungi and are similar microscopically. The season is from April to early October with great fluctuations in counts from day to day. This is probably due to the effect of weather. Very high counts are observed from late May to late September. Could be significant in causing allergic reactions.
Erysephe (Oospora)- Powdery mildew - The season is from late April to mid-October. Low to high counts are observed with daily fluctuations occuring.
Boletus sp.- The counts for this spore do get very high and may be of significance in causing allergic reactions. The season is late June to early October.
Coprinus sp.- This mushroom can produce very high counts from mid-May to mid-October. It is considered to be an important allergen.
Ganoderma sp.- This bracket fungus can produce very high counts from June to the end of September. Can be a significant allergen.
Uredinales- The rusts do produce high numbers but not enough is known about their significance in causing allergic reactions. The season is from late May to mid-October.
Ustilaginales- The smuts can reach very high counts, and their allergenicity is unknown. The season is April to mid-October.
Alternaria sp.- The counts do get high and some species are known to cause allergic reactions. The season is from mid-March to well into October. The highest counts are observed from July to mid-October.
Penicillium and Aspergillus sp.- These spores are found throughout the whole counting season and are probably present in significant numbers beyond that. High counts are observed from mid-March and well into fall.
Botrytis sp.- This may be a significant allergen although the counts do not get very high. The season is from May to mid-October.
Cladosporium sp.- The most abundant spore found throughout the whole season. Some species are known to cause allergic reactions. This spore exists all year round but very high counts are known to occur from March to well into late fall.
Epicoccum sp.- Some species are known to cause allergic reactions. The season, with significant counts, is from July to mid-October.
Fusarium sp.- Counts are very sporadic throughout the whole counting season. The majority of the season occurs from mid-May to the end of September with some high counts.
Helicomyces sp.- Season is from May to the end of September producing moderate and high counts. The season is very sporadic.
Pithomyces sp.- Season is mostly in the low to moderate ranges from the end of June to mid-October.
Torula sp.- Can cause allergic reactions. The season is from June to mid-October with low to moderate counts.
Stemphylium sp.- The season, with moderate counts, is from August to the end of September. Low counts can be observed from June to mid-October.
Drechslera sp.- The counts are never very high. This is a summer and fall spore, with moderate counts occuring in August and September. There are other related genera, which are also found in air samples that can cause respiratory problems. One example is Bipolaris sp.
Myxomycetes- Moderate and high counts are observed from April to mid-October.
Last Updated: 07-April-2006
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