Fungi are often associated with warm, moist conditions. However, Alternaria alternata, is frequently associated with more arid areas of the world. To determine if in a temperate climate, Alternaria is more abundant during periods of low humidity and little rainfall we conducted the following study.
Data was retrieved from the Kansas City mold and spore database for a 15 year period from 1998 to 2012. Data from the winter months of November to February was excluded. Collections were taken with a Burkard device atop a 5 story building in the urban center of the metropolitan area. Slides were collected daily and evaluated by a NAB certified counter for the presence of Alternaria spores using the 12 traverse method. Spore counts for 4 hour intervals were stored in an Access database and analyzed using Excel.
Alternaria spore counts varied from 0 to 112 during the period with a mean of 4.9 (SD 7.9). Alternaria counts showed a strong positive correlation with temperature (r= 0.31) and a negative correlation with humidity (r= -0.12). There was no correlation with wind speed and wind direction and a negative correlation with daily rainfall (r=-0.08). There was a strong correlation with rainfall during the previous month (r=0.18) and previous week (r=0.39).
Increased levels of Alternaria spores are related to times of warmer temperatures and lower humidity. Alternaria can take advantage of recent rainfall and enhanced growth conditions, but is also able to adapt to drier climates.
- AAAAI 2014 (70th)