Summary
Very low temperatures with frost, rain and snow in some areas continue to inhibit the release of pollen and moulds. Despite this, spring trees are stirring and cypress pollen is increasing when there are drier, warm conditions. No significant pollen or mould concentrations were detected at any of these sampling sites.
Cape Town
Once again, all pollen and mould concentrations were found in low quantities during this prolonged period of rain and low temperatures. No grass or weed pollen was seen and the only tree pollen recovered from the pollen strip was cypress (Cupressaceae).
Johannesburg
All pollen and mould concentrations remain low during this unusually cold midwinter period. Trees are starting their flowering season and included acacia (Acacia-type), Australian pine (Casuarina, the flamboyant tree (Delonix), beech (Fagus sylvatica), gum (Myrtaceae), olive (Oleaceae), karee (Rhus/ Searsia) and pine (Pinaceae). Weeds were slangbos (Stoebe-type). Last week’s findings are repeated here.
Pretoria
4-year means are shown. Trees flowering now would be cypress (Cupressaceae), yellowwood (Podocarpaceae), pine (Pinaceae), poplar (Populaceae) and ash (Fraxinus). Weeds would be the daisy family (Asteraceae) and plantain (Plantaginaceae).
Bloemfontein
Low tree concentrations included sumac (Anacardiaceae), cypress (Cupressaceae), olive (Oleaceae) and karee (Rhus/Searsia). In the weed category, only goosefoot (Chenopodiaceae) was detected. Grasses and moulds were sparse.
Kimberley
No grass was detected during this sampling period. Trees were the sumac family (Anacardiaceae), ash (Fraxinus) and poplar (Populaceae). Weeds included the daisy family (Asteraceae) and knotweed (Persicaria). Moulds were found in very low concentrations.
Durban
Insignificant concentrations for all pollen and mould species occurred throughout this sampling week. No grass pollen was detected. Trees included birch (Betulaceae), cypress (Cupressaceae), mulberry (Moraceae), poplar (Populaceae) and pine (Pinaceae). Weeds were knotweed (Persicaria) and nettles (Urticaceae).
Gqeberh
Extremely low grass concentrations were observed at this site. No tree pollen was detected and low weed concentrations included the daisy family (Asteraceae) and reeds (Restionaceae). Moulds were very low.
Potchefstroom
This site is not operating.
George
The very low concentrations of all pollen and moulds continued during this sampling week. No grass pollen was detected and trees were the sumac family (Anacardiaceae), ash (Fraxinus) and poplar (Populaceae). Weeds were the daisy family (Asteraceae) and knotweed (Persicaria).
Reference Range
Grass: Low: 0-5 Moderate: 6-20 High: 21-200
Trees: Low: 0-15 Moderate: 16-90 High: 91-1500
Weeds: Low: 0-10 Moderate: 10-50 High: 51-500
Moulds: Low: 0-900 Moderate: 900-2500 High 2500-25000
Unit: per cubic metre
