Weekly Report

29 April 2022

City
Overall Risk
Tree Pollen
Grass Pollen
Weed Pollen
Mould Spores

Summary

Moulds increased sharply in KwaZulu-Natal, following heavy rains in this subtropical climate zone. Strong spikes for ascospores and basidiospores (includes mushrooms) were seen. Pollen levels were low at all the sampling sites except Calvinia, where a small spike in the grass counts was observed. Trees were very low at all the sampled sites and weeds were similarly low.

Cape Town

Tree, grass and weed pollen has been reduced as winter approaches. Trees detected were gum (Myrtaceae), waxberry (Morella sp.), karee (Rhus/Searsia sp.), forest elder (Nuxia sp.) and Australian pine (Casuarina sp.). Weeds were mugwort (Artemisia sp.), the daisy family (Asteraceae), nettles (Urticaceae) and protea (Proteaceae). Moulds were very low.

Calvinia

Grass counts were high during this sampling period, but tree and weed levels were not significant. The trees detected were the sumac family (Anacardiaceae), bushwillow (Combretaceae), gum tree (Myrtaceae) and olive (Oleaceae). Weeds recorded included the daisy family (Asteraceae), the cabbage family (Brassicaceae), goosefoot (Chenopodiaceae), the carnation family (Caryophyllaceae), erica (Ericaceae) and nettles (Urticaceae). Moulds were low.

Johannesburg

Very low pollen and mould levels were seen across all categories. Tree pollen included mulberry (Moraceae), gum (Myrtaceae), oak (Quercus sp.) and elm (Ulmaceae). The weeds detected were erica (Ericaceae) and fern spores (Polypodiaceae).

Pretoria

Pollen and mould counts were not significant during this sampling period. The tree pollen detected were cypress (Cupressaceae), ash (Fraxinus sp.), gum (Myrtaceae), oak (Quercus sp.) and willow (Salix sp.). Weeds included the daisy family (Asteraceae), the carnation family (Caryophyllaceae), goosefoot (Chenopodiaceae), sedges (Cyperaceae), erica (Ericaceae) and slangbos (Stoebe-type).

Bloemfontein

Grasses were low during this sampling period. No tree pollen was detected. Weeds were low and included mugwort (Artemisia sp.) and nettles (Urticaceae). Moulds were low.

Kimberley

Courier delays meant no new data were available, so results from last week are repeated. Grasses were moderate, as rain reduced pollen in the air on some days of this sampling period. No tree pollen was detected but occasional weeds included ragweed (Ambrosia sp.), mugwort (Artemisia sp.) and goosefoot (Chenopodiaceae). Moulds were low.

Durban

Grasses were low. Low tree pollen levels included pine (Pinaceae) and gum (Myrtaceae). Weeds were the daisy family (Asteraceae), sedges (Cyperaceae), ferns (Polypodiaceae) and nettles (Urticaceae). Moulds were high after heavy rain, with high basidiospore and ascospore loads.

Gqeberha

Low counts were detected in all pollen and mould categories. Tree pollen included the sumac family (Anacardiaceae) and Australian pine (Casuarina sp.). Weeds included katstert (Anthospermum sp.), mugwort (Artemisia sp.), sedges (Cyperaceae) and slangbos (Stoebe-type).

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