The pollen and fungal spore counts all remained below the significant threshold during the recent sampling period. Rain regularly removed pollen and fungal spores from the ambient air. However, the constant low background presence of Cupressaceae (cypress pollen) as well as the small increases in Pleospora and Cladosporium indicate that seasonal changes are at play and that night temperatures are increasing.
Trees are beginning their pollinating cycle. Cypress and pine tree pollen grains are appearing in the atmosphere in increasing numbers. Pleospora continues to dominate the fungal spore load and ascospore levels increase after rainfall so there has been a constant present of ascospores in the air for the past three weeks.
The most recent sampling period was extremely cold with rain. These conditions would have inhibited the proliferation of fungal spores. Pollen levels were similarly low, but the appearance of Cupressaceae (cypress tree) pollen signals the approach of the end of winter.
The fungal spore and pollen levels were generally low with the exception of a small spike for Pleospora, an allergenic spore that shares antigens with Alternaria and Stemphyllium. The low temperatures and rain would have contributed to the dearth of air spora.
The copious rain that fell over much of the Western Cape during the last week, washed fungal spores and pollen from the atmosphere. However, intermittent moderate levels of ascospores were seen.
The fungal spore rose in response to rain as ascospore levels increased. Some early winter pollen grains are appearing, such as daisy and cypress tree pollen, but these are present in low numbers.
The unseasonally warm days, with cool, but not cold nights and little rain has given rise to low pollen and fungal spore levels during this late autumn period.
The recent rains have provided the moisture necessary for the proliferation of fungal spores, after an unseasonally dry autumn. Ascospore levels rose sharply and significant levels were observed during the recent sampling week. Cladosporium levels also increased but did not breach the significant threshold of 3000 spores / cubic metre. Tree, grass and weed pollen levels were consistently low.
The next update will be delayed until April. Tree and grass pollen levels are likely to remain low, weed pollen levels will increase as autumn progresses and the fungal spore levels will increase in response to rain,
The significant levels for Alternaria continued during this sampling period, when counts exceeding 100 spores/cubic metre were observed. Grass, tree and weed levels were low.