Predominant Pollen and Spores
Winnipeg, Manitoba
Tree pollen and spore seasons fluctuate from year to year by as much as two to four weeks at this site due to the effect of weather. The pollen and spore seasons described here are generalizations as to when pollination/sporulation occurs.
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Predominant Pollen for Winnipeg, Manitoba
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.
Alder (Alnus sp.)
Alder season can begin from the end of March to mid-April, depending on the weather. The season can end early to late June. The counts fluctuate from low to moderate throughout the season and the occasional high count can be observed. This is due to the number of species present and the effect of weather. They can be considered important allergens.
Amaranthaceae & Chenopodiaceae
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 about mid-June to early October.
Ash (Fraxinus sp.)
Ash pollen season can begin from mid-April to the third week of May and ends late-May to mid-June. The total pollen produced can vary a great deal at this location. 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.
Birch (Betula sp.)
Birch season can vary by as much as a month from year to year. The start of season can be from the third week of April to the third weeek of May and can end late May to mid-June. Low to high counts are observed. They are considered important allergens.
Cedars, Junipers and Yew (Cupressaceae family)
Cedars, junipers and yews season is very sporadic. The season can start mid-March to mid-April and ends early to late June. Mostly low and moderate counts (high counts occasionally occur depending on the season). The season fluctuates due to the effect of weather. Probably of no significance in causing allergic reactions.
Elm (Ulmus sp.)
Elm are important allergens. The pollen levels, as well as the timing for the pollen season, vary a great deal at this site. This has to do with the winter and spring temperatures as well as the number of species present. In warm years, like 2012, the season can start as early as late March. Generally the season starts early April to early May and end from early May to late May.
Grasses (Gramineae family)
Grasses produce moderate and high counts from the end of May to the end of July. The season is from mid-May to almost mid-October.
Hazel (Corylus sp.)
Hazelnuts have a season lasting approximately two to three weeks. The season can start early to late April and end late April to mid-May. Mostly low, with the occasional moderate, counts are observed.
Maple (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 mid-May to early June.
Mugwort (Artemisia sp.)
Mugworts can cause allergic reactions. The season can start from mid to late July and ends early to mid-October. Some moderate counts occur from August to mid-September.
Mustards and Cabbage (Brassica sp.)
Mustard and cabbage family are responsible for contact dermatitis and food allergies. They are not considered important in airborne allergies since they are mostly insect pollinated but a significant amount of pollen is observed in our samples at this location. The season starts late June to mid-July and lasts until mid to late August. Mostly low, with the occasional moderate, counts are observed.
Nettles (Urticaceae sp.)
The counts for the Nettles and parietaria occur in significant numbers that may cause allergic reactions. The season can start from mid-June to early July and ends around mid-September. They are considered important allergens due to their small size.
Oak (Quercus sp.)
Oak can have two seasons. Seasons can start from late April to late May and end late May to the third week of June. Some years the early season is almost non-existant due to the effect of weather. Oaks are highly allergenic.
Pine, fir and spruce (Pinaceae family)
Very high counts are observed at this site for pine, fir and spruce. 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.
Plantains (Plantago sp.)
Plantain can play an important role in allergic reactions, even at low levels. The counts are only in the low ranges from late June to mid-September.
Poplar, cottonwood and aspen (Populus sp.)
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.
Ragweed (Ambrosia sp.)
Low counts of ragweed pollen season can start from the second week to the third week of July and end mid-October or with a hard frost. Moderate and high counts occur from August to mid-September. They are considered important allergens.
Sagebrush (Artemisia sp.)
Low counts of Sagebrushes can cause allergic reactions. The season can start from mid to late July and ends early to mid-October. Some moderate counts occur from August to mid-September.
Willow (Salix sp.)
Willows can vary a great deal from year to year. Not only in the start and end dates but also the amount of pollen produced. The season can start from mid-April to mid-May and end late May to mid-June. May not cause allergic reactions except in highly sensitized individuals.
Predominant Spores for Winnipeg, Manitoba
Spore seasons fluctuate from year to year by as much as two to four weeks at this site due to the effect of weather. Spores described here are generalizations as to when sporulation occurs.
Alternaria sp.
Alternaria 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.
Aspergillus sp.
Aspergillus 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.
Boletus sp.
Boletus counts get very high and may be of significance in causing allergic reactions. The season is late June to early October.
Botrytis sp.
Botrytis may be a significant allergen although the counts do not get very high. The season is from May to mid-October.
Cladosporium sp.
Cladosporium is 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.
Coprinus sp.
Coprinus mushroom can produce very high counts from mid-May to mid-October. It is considered to be an important allergen.
Diatrypaceae sp.
Diatrypaceae counts are sporadic with high counts throughout the counting season. The season is from late March to mid-October. Not known to cause allergic reactions.
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.
Epicoccum sp.
Some species of epicoccum are known to cause allergic reactions. The season, with significant counts, is from July to mid-October.
Erysiphe (Oospora) sp.
Erysiphe, commonly referred to as powdery mildew, season is from late April to mid-October. Low to high counts are observed with daily fluctuations occuring.
Fusarium sp.
Fusarium 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.
Ganoderma sp.
Ganoderma or bracket fungus can produce very high counts from June to the end of September. Can be a significant allergen.
Helicomyces sp.
Helicomyces season is from May to the end of September producing moderate and high counts. The season is very sporadic.
Leptosphaeria sp.
Leptosphaeria 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. No known allergic properties.
Myxomycetes
Moderate and high counts are observed from April to mid-October.
Penicillium sp.
High counts of Penicillium 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.
Pithomyces sp.
Pithomyces season is mostly in the low to moderate ranges from the end of June to mid-October.
Polythrincium sp.
Moderate counts of polythrincium are observed from mid-June to mid-October. Medical significance is unknown.
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.
Torula sp.
Torula sp. can cause allergic reactions. The season is from June to mid-October with low to moderate counts.
Uredinales sp.
Uredinales also know as 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 sp.
Ustilaginales also know as smuts, can reach very high counts, and their allergenicity is unknown. The season is April to mid-October.
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