Allergen Update
Hamilton, 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 maple season can start from early to mid-March and end between mid and late May. Moderate and high counts are observed. Certain species are known to cause allergic reactions.
Alnus sp.- Alder season occurs from early March to the end of May with fluctuations in the counts from low to high due to the number of species present. The season is highly affected by the weather and significant counts can be observed for about a week during the month of April.
Betula sp.- The birch season, with significant counts, can occur between mid-April to late May with counts ranging from low to high. The season changes from year to year which is due to the number of species present and the effect of weather. Birch look-a-likes' season lasts about one month and can occur from mid-April to about late May and the counts are in the low to moderate range.
Populus sp.- The poplars and aspens season can occur between late March to early April. The season lasts approximately one month. Some of the counts are high and may cause allergic reactions.
Cupressaceae group- The cedars, junipers, and yews produce low to high counts and the season varies a great deal from year to year. The season can occur from (March to approximately mid-May).
Fraxinus sp.- The ash pollen season lasts approximately four weeks and can occur from mid-April to early June. Some low to high counts are observed and they are considered to be allergenic only in highly sensitized individuals.
Pinaceae group- This includes the spruce, fir and pine trees. Some high counts are observed and the occurence of the pollen season can vary from year to year. The season can start from late April to mid-May and can end mid to late June.
Quercus sp.- The oaks have two distinct flowering periods which is due to the different species present. The seasons are affected by weather conditions. The first season, which lasts approximately one week, can have low to high counts and occurs during the month of April. The second season, which can last over a month, can occur from late April through to early June. Some of the species are considered highly allergenic.
Salix sp.- Pollination lasts for more than one month and can occur from mid-April to early June with moderate counts observed. They are considered to be allergenic only in highly sensitized individuals.
Carya sp.- The hickories have a short early season, lasting approximately one week, and moderate counts are observed. This early season occurs in May. The main season lasts about two to three weeks and can occur in May or June.
Juglans sp.- The walnuts are considered important in causing allergic reactions. The pollen season can start early May to mid-May and can end late May to mid-June. Low to high counts are observed at this site.
Ulmus sp.- The elms are considered important allergens. There are two distinct seasons and the first can occur early to late March and lasts about one week. The second season lasts about one month and can occur from late March to late April. Some high counts are observed but the seasons can vary due to the effect of weather.
Morus sp.- The mulberries produce very high counts at this site. The pollen season lasts approximately four weeks and can occur from early May to early June. Could be a significant allergen for those individuals who are sensitized.
Gramineae- The grass season is from the beginning of May to October. Low to high counts are observed from the end of May to mid-July.
Ambrosia sp.- Ragweed pollen is observed from late July to late October. Moderate to high counts are obtained in August and September.
Urtica sp.- Nettles pollinate from June to late September and moderate to high counts are observed from mid-July to August. This may cause allergic reaction in highly sensitized individuals.
Plantago sp.- The plantains pollinate from June to early October. The counts are generally in the low range and occasionally moderate. They may cause allergic reactions in highly sensitized individuals.
Predominant spores:
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 is May to early October with fluctuations in counts from day to day which is probably due to the effect of weather. Highest counts are observed from May to the end of September.
Erysephe (Oospora)- Powdery mildew - The season is from April to mid-October. Low to high counts are observed. Allergenic properties are not well understood.
Boletus sp.- The counts for this mushroom do get high and may be significant in causing allergic reactions. The season is July to mid-October.
Coprinus sp.- This mushroom can produce some very high counts from May to late October. It is considered an important allergen.
Ganoderma sp.- This bracket fungus can produce very high counts from June to late October. It is considered an important allergen.
Uredinales- The rusts do not occur in really high numbers and allergenic properties are not well understood. The season is from June to late October.
Ustilaginales- The smuts can reach high counts, and their allergenicity is unknown. The season is from May to late October. Very high counts are observed in September and October.
Alternaria sp.- Some high counts are observed and certain species are known to cause allergic reactions. The season is from mid-April to the end of October with the highest counts occuring from June to 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 June to well into October.
Cladosporium sp.- The most abundant spore found throughout the whole season. This spore exists all year round but the highest counts occur from May to late October. Some species are known to cause allergic reactions.
Epicoccum sp.- Some species are known to cause allergic reactions. The season is from May to late October with some low to high counts.
Fusarium sp.- Counts are sporadic throughout the whole counting season. The majority of the highest counts are observed from May to late September.
Helicomyces sp.- Season is from April to mid-September producing moderate and very high counts. The season is very sporadic.
Torula sp.- Moderate counts are observed from July to September.
Polythrincium sp.- Moderate counts are observed from mid-August to the end of September.
Pithomyces sp.- Few moderate counts are observed late July to early October.
Myxomycetes- Few moderate counts are observed from June to late September.
Last Updated: 06-April-2006
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