Insecticide resistant annual bluegrass weevil: Understanding, managing, alleviating, and preventing a superintendent's nightmare

The annual bluegrass weevil (ABW), Listronotus maculicollis, is a serious and expanding golf course pest in the Northeast. Recently, decreased efficacy of pyrethroid adulticide applications and pesticide-resistant populations are reported from an increasing number of golf courses (Ramoutar et al. 2009a). The efficacy of most insecticides against pyrethroidresistant ABW populations seems to be reduced on average by 15-57%, but for pyrethroid resistant ABW populations is extremely limited (Koppenhöfer et al. 2012). To develop good recommendations for the mitigation of ABW resistance it is essential to better understand the degree and scope of resistance (different ABW stages, different insecticide modes of action) and the resistance mechanisms involved. Practical assays for resistance detection and monitoring also need to be developed. Topical bioassays were conducted to determine resistance levels and cross resistance patterns to the major insecticide modes of actions in adult ABW (Table 1). Nine different populations were collected from golf courses with different histories of insecticide use and ABW infestation (Table 2). Six concentrations of the insecticide active ingredients (AI, technical grade) were applied topically (1 μl/adult) using microapplicators (Figure 1). Treated ABW were placed in Petri dishes (10 per dish) lined with moist filter paper with food provided Objectives: