Implementation and Evaluation of a Communication Strategy to Control Ragweed Pollen

The common ragweed ( Ambrosia artemisiifolia ) is widespread in southwestern areas of Quebec, Canada. It is known to release large quantities of pollen from July through September, triggering allergic reactions such as rhinitis and generating significant costs for public health. The objective of this study was to implement and evaluate a communication intervention aimed at decreasing ragweed pollen. Selected lands with potential ragweed presence were visited twice, before and after the intervention, on three seasons in the East of the Montreal Island, Quebec. At the first visit done in 2010, 2011, and 2012, ragweed plots were located and measured; at the second visit in 2012, the measures were redone. Various numbers of communications were sent to owners of ragweed-infested lands that included explanations of health impacts of ragweed pollen and the importance of mowing. Mixed logistic regressions were used to test the effect of the number of communications on the mow. In the group that received four notices, a statistically significant three-fold increase in the proportion of land owners that had cut ragweed plots (OR = 3.20; 95 %CI: 1.16-8.84) was noted, compared to the group that received only one notice. For owners of vacant lands, the effect was somewhat more pronounced (OR = 3.82; 95%CI: 1.23-11.67). Nonetheless, the change from one to three communications showed no increase of mowing. In conclusion, the results of the present study suggest that communications and reminders of the importance of ragweed cut to landowners could be an effective measure to limit ragweed pollen.