Summary
The continued rain, low temperatures and frost has reduced all pollen and mould loads in the air. Spring tree pollen is seen on days with sun but the concentrations remain low at all sampling sites.
Cape Town
No pollen was detected during this sampling period. Torrential rain with flooding was experienced for most of the week. Moulds were low with occasional peaks for ascospores and a small but insignificant increase in the rain spore, Pleospora.
Johannesburg
Extremely low concentrations of grass and weed pollen were noted at this site. Trees included cypress (Cupressaceae), beech (Fagus sylvatica). Pine (Pinaceae) and karee). The tree pollen concentrations are low, but cypress pollen in the air is increasing. Weeds were lily (Liliaceae) and moulds were very low indeed.
Pretoria
4-year means are given. Pollen concentrations are low at this time. Trees are mulberry (Moraceae), bushwillow (Combretaceae) and poplar (Populaceae). Weeds would be slangbos (Stoebe-type) and moulds are scarce.
Bloemfontein
The tree, grass, weed and mould concentrations were all very low. Trees included birch (Betulaceae), bushwillow (Combretaceae), cypress (Cupressaceae), pine (Pinaceae), oak (Quercus) gum (Myrtaceae), plane (Platanaceae) and karee (Rhus/Searsia). Weeds were the daisy family (Asteraceae), sedges (Cyperaceae) and ferns (Polypodiaceae).
Kimberley
Very few pollen grains were detected. Trees included poplar (Populaceae) and weeds were ferns (Polypodiaceae). No grass was seen and moulds were extremely low.
Durban
Extremely low pollen and mould concentrations were detected at this sampling site. No tree or weed pollen was seen and only spurges (Euphorbiaceae) represented the weeds.
Gqeberha
The low pollen and mould concentrations persisted this week. The only tree pollen detected was karee (Rhus/Searsia). Weeds were the carrot/celery family (Apiaceae), the daisy family (Asteraceae) and sedges (Cyperaceae). Moulds were low, with small, insignificant peaks for ascospores and basidiospores (mushrooms).
Potchefstroom
This site is not operating.
George
The heavy rain damaged the pollen strip. No tree or grass pollen was detected and the only weeds identified were spurges (Euphorbiaceae). Moulds were very low.
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
