Are Tobacco-Adapted Aphids (Myzus persicae) More Tolerant to Neonicotinoid Pesticides?

Since the introduction of neonicotinoid pesticides it was hypothesized that tobacco-adpated pests, such as the green peach aphid (Myzus persicae), would be resistant to this new chemistry. This prediction was quickly rejected and, due to its effectiveness in tobacco fields, currenlty about 90% of growers in NC use pre-transplant application of neonicotinoids. While we have not seen resistance in tobacco fields for any of the neonicotinoids, the hypothesis of differences in tolerance between tobacco-adapted aphids and its non-tobacco counterparts has never been tested. To answer that question, we raised four isofemale line from tobacco-adapted aphids collected in different fields in NC and two non-tobacco lines donated by the University of Miami. We measured the tolerance to both nicotine and imidacloprid by exposing the aphids to different concentrations of the chemicals in an artifical diet. Differences in mortality between the lines showed that non-tobacco aphids are less tolerant to nicotine, while also less tolerant to imidacloprid. The tobacco-adapted lines are variable in their tolerance to imidacloprid. While none of the lines we examined would be considered resistant to imidacloprid under field conditions, there is higher tolerance in some tobacco-adapted clones, highlighting the importance of resistance management for this materials in tobacco.