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THOLEN – The 2021 hay fever season is almost over. Most grasses and herbs have finished flowering. That reports Weeronline.nl. At the moment mugwort still causes regional complaints and in September the wormwood ragweed can still cause serious complaints locally. This herb locally spreads very strong allergenic pollen and can cause serious complaints. That reports Weeronline.nl
According to the pollen planner at Wageningen University, the flowering period of wormwood ragweed will start this week. The flowering peak is expected around September 10. The wormwood ragweed is especially often found at bird feeders. Wormwood ragweed can also occur on roadsides, on construction sites and in fields.
The weather is expected to be slightly changeable in the near future, according to Weeronline. A north to northeast wind sometimes brings cloud fields and a few showers, but there are also long dry periods. Sometimes several days in a row are dry.
The wormwood pollen is light and can travel hundreds of kilometers through the air under certain conditions. North to northeast winds often bring clean air, but Wormwood pollen from Ukraine and Belarus may reach our country next week via Germany and Denmark. However, high pollen concentrations are not to be expected on a large scale in the Netherlands. In the immediate vicinity of wormwood plants, the pollen concentration can rise very sharply.
Climate change
Due to the warming climate, the conditions for the Alsemambrosia in the Netherlands will become increasingly favorable. The main flowering period of the ragweed, in August and September, has warmed by 1.7 degrees since the beginning of the last century.
High temperatures late in the season increase the chance that the plants will set seed. A single plant can produce 3000 to 4000 seeds that remain germinable for 40 years. The number of places where ragweed occurs has been increasing for years.
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