Weekly Report

22 October 2021

City
Overall Risk
Tree Pollen
Grass Pollen
Weed Pollen
Mould Spores

Summary

High grass counts were seen in Cape Town, with low counts still observed in the summer rainfall areas. Tree pollen showed a significant increase in Johannesburg but decreased in Cape Town and remained low at the other sites. High levels of charcoal particles were seen in Bloemfontein due to fires. Overall low pollen and fungal spore levels for most of the country.

Cape Town

Pollen levels decreased this week due to the recent rain and increased relative humidity, but significant grass levels were seen on warm still days. Tree levels are decreasing but a variety of tree pollen was detected including olive (Oleaceae), cypress (Cupressaceae), gum (Myrtaceae), birch (Betulaceae), plane (Platanaceae), Australian pine (Casuarina sp.), pine (Pinaceae), yellowwood (Podocarpaceae), oak (Quercus sp.), mulberry (Moraceae), the sumac family (Anacardiaceae) and karee (Rhus sp. / Searsia sp.). Low weed levels included nettle (Urticaceae), English plantain (Plantago sp.), erica (Ericaceae), the mezereum family (Thymelaeaceae), the daisy family (Asteraceae), sorrel (Rumex sp.), knotweed (Polygonaceae), sedges (Cyperaceae), protea (Proteaceae) and the borage or forget-me-not family (Boraginaceae). Moulds were low.

Johannesburg

Low grass and weed counts, with low to moderate tree counts were seen. Tree pollen included the sumac family (Anacardiaceae), birch (Betulaceae), hackberry (Celtis sp.), bushwillow (Combretaceae), cypress (Cupressaceae), sand olive (Dodonaea sp.), ash (Fraxinus sp.), mulberry (Moraceae), gum (Myrtaceae, pine (Pinaceae), plane (Platanus sp.), poplar (Populus sp.), oak (Quercus sp.) and karee (Rhus sp. / Searsia sp.). The weed pollen detected were sedges (Cyperaceae), the daisy family (Asteraceae), the carnation family (Caryophyllaceae), goosefoot (Chenopodiaceae) and fern spores (Polypodiaceae). Mould counts were low.

Pretoria

A strong increase in tree pollen was seen, with acacia (Acacia sp.), the sumac family (Anacardiaceae), ash (Fraxinus sp.), birch (Betulaceae), cypress (Cupressaceae), bushwillow (Combretaceae), waxberry (Morella sp.), mulberry (Moraceae), gum (Myrtaceae), olive (Oleaceae), pine (Pinaceae), plane (Platanaceae), yellowwood (Podocarpaceae), poplar (Populus sp.) and oak (Quercus sp.) detected. Pollen grains from the peacock flower subfamily was also found, which is currently identified as mesquite (Prosopis sp.). Low weed pollen was detected, including lilies (Liliaceae), the carnation family (Caryophyllaceae), sedges (Cyperaceae), spurges (Euphorbiaceae), fern spores (Polypodiaceae) and nettles (Urticaceae). Grass and mould levels were low.

Bloemfontein

Overall low counts for this site, with low levels of trees, grasses weeds and moulds recorded. Tree pollen included bushwillow (Combretaceae), waxberry (Morella sp.), gum (Myrtaceae), mulberry (Moraceae), karee (Rhus sp. / Searsia sp.), plane (Platanus sp.) and pine (Pinaceae). The weed pollen detected were the daisy family (Asteraceae), goosefoot (Chenopodiaceae), erica (Ericaceae) and pigmyweeds (Crassula sp.). Numerous charcoal particles were seen due to managed burning in and around Bloemfontein.

Kimberley

Tree, grass and weed pollen were low. Trees included cypress (Cupressaceae), bushwillow (Combretaceae), ash (Fraxinus sp.) and the sumac family (Anacardiaceae). Weeds included the daisy family (Asteraceae), the carnation family (Caryophyllaceae), nettle (Urticaceae) and protea (Proteaceae). Moulds were low. Charcoal was seen on the strip, but the quantity has decreased since the veld fires of two weeks ago.

Durban

Tree, grass and weed pollen levels were all low. Trees included acacia (Acacia sp.), pine (Pinaceae), yellowwood (Podocarpaceae), mulberry (Moraceae), birch (Betulaceae), Australian pine (Casuarina sp.), gum (Myrtaceae), plane (Platanaceae), cedar (Cedrus sp.), cypress (Cupressaceae) the walnut family (Juglandaceae) and ash (Fraxinus sp). Weeds detected were the daisy family (Asteraceae), nettles (Urticaceae), the carnation family (Caryophyllaceae), sorrel (Rumex sp.) rushes (Juncaceae) and sedges (Cyperaceae). Moulds were low with small spikes for Cladosporium and ascospores.

Gqeberha

Grass, tree, weed and mould counts were low during this sampling period. Tree pollen included acacia (Acacia sp.), the sumac family (Anacardiaceae), cedar (Cedrus sp.), Australian pine (Casuarina sp.), gum (Myrtaceae), pine (Pinaceae) and yellowwood (Podocarpaceae). The weeds detected were pigweed (Amaranthus sp.), katstert (Anthospermum sp.), sedges (Cyperaceae), the daisy family (Asteraceae), the carnation family (Caryophyllaceae), heath/erica (Ericaceae) and mezereum (Thymelaeaceae).

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