Weekly Report

31 December 2021

City
Overall Risk
Tree Pollen
Grass Pollen
Weed Pollen
Mould Spores

Summary 

Pollen analysis was carried out in Cape Town, Bloemfontein and Johannesburg. Estimated values are given for the other sites where access is restricted due to covid or holiday schedules. Pollen levels are generally low throughout the country but grasses will increase in summer rainfall areas from January. Trees and weeds are low and moulds are generally low but at this time of the year moulds are high in Durban.

Cape Town: The dry warm weather depressed the mould levels that have been showing small spikes following rain in recent weeks. Grasses were low to moderate. Tree pollen is now waning and included pine (Pinaceae), olive (Oleaceae), cypress (Cupressaceae), gum (Myrtaceae), waxberry (Morella sp.), the persimmon family (Ebenaceae) and the monkey puzzle tree (Araucaria angustifolia). Weeds were sedges (Cyperaceae), bulrushes (Typhaceae), English Plantain (Plantaginaceae), nettles (Urticaceae), mezereum (Tymelaeaceae), the daisy family (Asteraceae), sorrel (Rumex sp.) and ericas (Ericaceae).

Johannesburg: All pollen levels were low during this sampling period. Tree pollen included Australian pine (Casuarina sp.), mulberry (Moraceae) and plane (Platanaceae). No weed pollen was detected and moulds were uniformly low.

Pretoria: Small spikes may occur for grasses following rain but the main grass season is still approaching. Tree pollen could include pine (Pinaceae), yellowwood (Podocarpaceae), mulberry (Moraceae) and Australian pine (Casuarina). Weed pollen typically detected is nettle (Urticaceae), the daisy family (Asteraceae) and goosefoot (Chenopodiaceae). Moulds may increase after rain but are generally low.

Bloemfontein: Grass pollen ranged from low to moderate. Pollen in the categories of trees and weeds was low during this sampling period. Trees detected included mulberry (Moraceae), waxberry (Morella sp.) gum (Myrtaceae) and olive (Oleaceae). Weeds were goosefoot (Chenopodiaceae), the daisy family (Asteraceae), pigmyweeds (Crassulaceae) and English Plantain (Plantaginaceae). Moulds were low.

Kimberley: The pollen levels are generally low in December ahead of the grass season. Tree pollen could include the sumac family (Anacardiaceae), olive (Oleaceae) and karee (Rhus/Searsia sp.). Moulds are usually low but strong spikes for Cladosporium and/or Alternaria are often seen in December when rain is followed warm temperatures.

Durban: Fungal spores/moulds are high in December and large spikes may be seen for Cladosporium, ascospores and Alternaria. Tree pollen would include mulberry (Moraceae), Australian pine (Casuarina sp.), the monkey puzzle tree (Araucaria angustifolia), pine (Pinaceae), gum (Myrtaceae), the sumac family (Anacardiaceae) and olive (Oleaceae). Weeds may include goosefoot (Chenopodiaceae), nettles (Urticaceae), English Plantain (Plantaginaceae) and the daisy family (Asteraceae).

Gqeberha: In December the prevailing wind is frequently very strong in December so the pollen and fungal spore catches are usually low. Tree pollen may include palms (Arecaceae), waxberry (Morella sp.) and olive (Oleaceae). Weeds identified are proteas (Proteaceae), ericas (Ericaceae) and the daisy family (Asteraceae). Moulds are usually low.

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