Allergen Update
Barrie, Ontario
Predominant pollen:
The tree pollen seasons can fluctuate from year to year by as much as two to four weeks at this site. The pollen seasons described here try to cover the time when each can occur.
Acer sp.- The main maple season lasts approximately four weeks and can occur from early April to late May with high counts observed. There is also a short season, lasting about one week, with moderate counts which can occur from late March to early April.
Alnus sp.- Alder season occurs from late March to mid-June and the counts vary from low to high due to the number of species present and the effect of weather. The season with the highest counts can occur from late March to late April.
Betula sp.- The main birch season lasts more than a month and can start from late April to early May and end mid-May to early June with high counts observed. The birch look-alikes' have two short seasons, lasting about one week, and they occur anytime in the month of May. These two groups are condisered important allergens.
Populus sp.- The poplars and aspens have two distinct seasons: the first one occuring from late March to early April and it usually lasts about one week. The main season, which lasts almost one month, can occur from late March to early May. Some of the counts are high and may cause allergic reactions.
Cupressaceae group- The cedars, junipers, and yews have a short early season that can occur from late March to early April. The second season lasts approximately four weeks with low to high counts. It can occur in the month of April and last into early May. May cause allergic reactions to highly sensitized individuals.
Fraxinus sp.- The ash pollination season can last more than a month. It starts from mid-April to mid-May and ends from mid-May to early June with high counts observed. Considered to be allergenic only in highly sensitized individuals.
Pinaceae group- The season for the spruces, firs and pines varies from year to year due to the effect of weather. The season lasts more than a month and can occur from early May to early July. Very high counts are observed and can be important in causing allergic reactions in individuals who are sensitized.
Quercus sp.- The oaks have two distinct seasons with low to high counts observed. The first one lasts approximately one week and can occur from mid to late April and the second one, which lasts about three weeks, can occur from early May to early June. Some species are considered highly allergenic.
Fagus sp.- The beech can produce low to moderate counts and the season lasts approximately two weeks during the month of May. The season varies from year to year due to the effect of weather. They may not cause reactions except in highly sensitized individuals.
Juglans sp.- The pollen season for the walnuts is highly affected by weather. The season can last almost a month and can occur from early May to early June. The pollen counts can vary from low to high during the season.
Ulmus sp.- The elms are considered important allergens. There is a short season, lasting approximately one week in late March. The main season, which can last almost two weeks, can occur between late March and late April with some high counts observed. The beginning and end of the season can vary from year to year.
Carya sp.- The hickories have a season lasting one to two weeks producing low to moderate counts and the season can occur from the second week of May to the second week of June. They can be considered important allergens. The season varies a great deal from year to year due to the effect of weather.
Morus sp.- The mulberries have two distinct seasons each lasting from one to two weeks and they occur from early May to early June. Some very high counts are observed and can cause allergic reactions.
Gramineae- The grass season is from late April to almost mid-October. Significant counts in the moderate and high ranges are observed from late May to late July.
Ambrosia sp.- Ragweed pollen is observed from late July to late October. Moderate and high counts are obtained from the second week of August to early October.
Plantago sp.- The plantains can play an important role in causing allergic reactions. The season is June to early October with sporadic moderate counts observed from July to mid-October.
Urtica sp.- The nettles pollen season is from June to mid-September with some moderate counts observed from early to mid-August. They can cause allergic reactions in individuals who are highly sensitized.
Predominant spores:
Diatrypaceae sp.- The counts are sporadic throughout the whole counting season. This fungus can produce very high counts from March to early October. They may not cause allergic reactions.
Leptosphaeria sp. & Leptosphaeria look-alikes- These two are grouped together since they are in the same class of fungi and are similar microscopically. The season is April to mid-October with fluctuations in counts from day to day. This is probably due to the effect of weather. The highest counts are observed from June to the end of September. They can cause allergic reactions.
Erysephe (Oospora)- Powdery mildew - The season is from mid-April to mid-October. Some high counts are observed. Allergenic properties are not well understood.
Boletus sp.- The counts for this spore do get high from June to early October and may be significant in causing allergic reactions.
Coprinus sp.- This mushroom can produce some very high counts from May to mid-October. It is considered an important allergen. This fungus produces significantly higher counts at this site than at most other sampling locations.
Ganoderma sp.- This bracket fungus can produce very high counts from June to late October. During the month of May, the counts are moderate to high. It is considered an important allergen.
Uredinales- The rusts do not occur in really high numbers but not enough is known about their significance in causing allergic reactions at these levels. The season is from mid-May to mid-October.
Ustilaginales- The smuts can reach high counts, but allergenicity is unknown. The season is May to late October.
Alternaria sp.- Some high counts are observed and certain species are known to cause allergic reactions. The season with high counts is from April to mid-October.
Penicillium & 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 late March to well into October.
Cladosporium sp.- The most abundant spore found throughout the whole season. This spore exists all year round but very high counts are known to occur from March to late October.
Epicoccum sp.- Some species are known to cause allergic reactions. The season is from April to late October with some high counts from July to mid-October.
Fusarium sp.- Counts are very sporadic from March to the end of September. The majority of the highest counts are observed from June to late September.
Helicomyces sp.- Season is from May to the end of September producing moderate and high counts. The season is very sporadic. Allergenic properties are not well understood.
Botrytis sp.- Considered an important allergen. Moderate counts are observed from May to late September.
Pithomyces sp.- Moderate and high counts are observed from mid-June to late September.
Myxomycetes- Moderate counts are observed from March to mid-October.
Last Updated: 03-March-2006
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