AIR-BORNE POLLEN SURVEYS IN MANITOBA AND SASKATCHEWAN

Abstract

Air-borne pollen was collected at 19 sites in southern Manitoba and Saskatchewan. Deciduous trees such as poplars and Manitoba maple produced the greater part of the air-borne pollen collected before the end of the first week in May. The peak period of grass pollen production occurred in the latter part of June and early July with small amounts being collected up to mid-September. Pollens from ragweeds and their relatives were only abundant at Morris and Emerson in the Red River Valley. At these two locations the peak ragweed pollen season was between July 27 and August 22. Of the other wind-pollinated plants causing hay fever only Russian thistle and wormwoods produced pollen in large amounts.