Allergen Update
Thunder Bay, Ontario
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, with moderate counts, lasts approximately two weeks and can occur in the month of May. There is also a short season during the month of April where the counts are mostly low. Some species are known to cause allergic reactions.
Alnus sp.- The alder season, with significant counts, can start from late March to mid-April and end early to mid-June. The counts fluctuate from low to very high due to the number of species present and the effect of weather.
Betula sp.- The start and end of the birch season can fluctuate a great deal due to the effect of weather. The season can start late April to late May and can end Mid-May to mid-June. The counts can be very high and can play an important role in allergic reactions. Birch look-a-likes' season lasts approximately one month, and can occur early May to early June. The counts are low to moderate.
Populus sp.- The poplar and aspen season can start from the second week of April to late April and can end from early to late May. Some of the counts are high and may cause allergic reactions.
Cupressaceae group- The cedars, junipers and yews produce low to high counts from late March to early May.
Fraxinus sp.- The ash pollination season lasts between two to four weeks and can occur between late April to early June with some high counts observed. Considered to be allergenic only in highly sensitized individuals.
Pinaceae group- This includes the spruce, fir and pine trees. Very high counts are observed and the season can start from early May to early June and end from late June to early July.
Quercus sp.- The oaks flower late April to early May and a second season occurs from mid-May to early June. They are considered highly allergenic.
Salix sp.- The season varies a great deal and lasts approximately two to four weeks from mid-April to the beginning of June and high counts can be observed.
Corylus sp.- The hazelnuts have a season lasting approximately two to three weeks and moderate counts are observed. Pollination can occur from mid-April to mid-May.
Gramineae- The grasses produce significant high counts from the second week of June to the end of July. The season is from mid-May to the end of September.
Ambrosia sp.- Ragweed pollen is observed from late July to mid-October. Some moderate counts occur from late August to mid-September.
Urtica sp.- Nettles pollinate late June to mid-September and moderate counts are observed from late July to mid-August. They may cause allergic reactions in highly sensitized individuals.
Plantago sp.- The plantains pollinate from July to the end of September with occassional moderate counts observed. They may cause allergic reactions in highly sensitized individuals even at low levels.
Predominant spores:
Note: This site is unique because during the late summer months (July to September) the predominant group of spores include the Basidiomycota. This group consists of many fungal spores and some are known to be highly allergenic.
Diatrypaceae sp.- The counts are sporadic throughout the whole counting season. High counts can be observed from March to well into 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, with significant counts, is May to early October, with great fluctuations in counts from day to day, which is probably due to the effect of weather. Very high counts are observed from May to early October. The Leptoshpaeria-look-alikes produce sporadic moderate and very high counts from May to mid-October.
Erysephe (Oospora)- Powdery mildew - The season is from mid-April to mid-October. Very high counts are observed. Allergenic properties are unkown.
Venturia sp.- This spore is very abundant at this site and the season is sporadic producing some very high counts from mid-May to mid-October. Allergenic properties are not well understood but it is mostly associated with apple scab.
Boletus sp.- The counts for this spore do get very high and may be significant in causing allergic reactions. The season is mid-June to mid-October.
Coprinus sp.- This mushroom can produce some very high counts from May through to mid-October. It is considered an important allergen.
Ganoderma sp.- This bracket fungus can produce very high counts from mid-June to mid-October. It is considered an important allergen.
Uredinales- The rusts do sometimes occur in really high numbers but not enough is known about their significance in causing allergic reactions at these levels. The season is from the end of May to mid-October.
Ustilaginales- The smuts can reach high counts, allergenicity is unknown. The season with significant counts is mid-May to mid-October with some high counts.
Alternaria sp.- Some high counts are observed and certain species are known to cause allergic reactions. The season with significant counts is from May to mid-October.
Penicillium & Aspergillus sp.- These spores are found throughout the whole counting season and are probably present in significant numbers beyond that. The highest counts are observed from March to well into October.
Botrytis sp.- This may be a significant allergen and the counts do get very high. The season is from May to early October with moderate and some high counts.
Cladosporium sp.- This spore is found throughout the whole season and exists all year round. Very high counts are known to occur from late March to well into October.
Epicoccum sp.- Some species are known to cause allergic reactions. The main season is from May to mid-October with low to moderate counts.
Fusarium sp.- Counts are very sporadic from April to mid-October. Some high counts are observed.
Helicomyces sp.- The main season is very sporadic from May to the end of September producing moderate and very high counts.
Polythrincium sp.- The season is from mid-June to the end of September with low to high counts observed. The allergenicity of this fungal spore is not well understood.
Pithomyces sp.- Season is mostly in the low to moderate range from mid-June to mid-October.
Caloplaca sp.- Sporadic counts are observed from March to mid-October. The allergenicity of this fungal spore is not well understood.
Myxomycetes- Moderate and high counts are observed from April to mid-October.
Last Updated: 22-March-2006
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