Potential distribution and relative abundance of swede midge, Contarinia nasturtii, an invasive pest in Canada

Abstract

The swede midge, Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), is a pest of most cultivated Brassicaceae such as broccoli, canola, cauliflower, cabbage, and Brussels sprouts. The species primarily has a Palaearctic distribution and occurs throughout Europe and southwestern Asia to the Caucasus. Between 1996 and 1999, producers of cruciferous vegetables in Ontario, Canada, reported crop damage that was consistent with damage symptoms characteristic of C. nasturtii feeding and in 2000, field studies confirmed that this damage was caused by C. nasturtii . A bioclimatic model was developed to predict potential range and relative abundance of C. nasturtii in Canada in order to determine the impact of the establishment and spread of C. nasturtii populations. Model output indicated that C. nasturtii could potentially become established in all provinces of Canada, with the risk being greatest in southwestern British Columbia, southern Ontario and Quebec, New Brunswick, Nova Scotia, and Prince Edward Island. Results indicated that C. nasturtii population growth in the Prairie Ecozone of western Canada would be greatest in years with above average precipitation.

Will climate change be beneficial or detrimental to the invasive swede midge in North America? Contrasting predictions using climate projections from different general circulation models

“…In brief, in accordance with previous observations (Readshaw, 1961), Olfert et al (2006) found that temperature and soil moisture are the most important variables affecting C. nasturtii's distribution, growth, and control. Their model was fit to reflect this information and resulted in a realistic representation of the insect's current distribution and phenology in Europe (Olfert et al, 2006). Olfert et al (2006) validated their BEM by comparing the model's resulting distribution with empirical observations of C. nasturtii for eastern Europe from five different sources of distribution data.…”

“…See Olfert et al (2006) for a complete discussion of model development, sensitivity, and validity. In brief, in accordance with previous observations (Readshaw, 1961), Olfert et al (2006) found that temperature and soil moisture are the most important variables affecting C. nasturtii's distribution, growth, and control.…”

“…See Olfert et al (2006) for a complete discussion of model development, sensitivity, and validity. In brief, in accordance with previous observations (Readshaw, 1961), Olfert et al (2006) found that temperature and soil moisture are the most important variables affecting C. nasturtii's distribution, growth, and control. Their model was fit to reflect this information and resulted in a realistic representation of the insect's current distribution and phenology in Europe (Olfert et al, 2006).…”

“…For this study, the parameter values determined by Olfert et al (2006) were used (Table 1). See Olfert et al (2006) for a complete discussion of model development, sensitivity, and validity.…”

“…Modelling has shown that this pest has the potential to become established in North America, with the Great Lakes region being one of the areas at greatest risk (Olfert et al, 2006). Olfert et al (2006) used data on C. nasturtii's distribution in Eurasia to construct a bioclimatic envelope model (BEM) using CLIMEX 2.0 (Sutherst et al, 2004). They then applied their BEM to Canada to investigate the potential risk of C. nasturtii's spatial spread.…”