Impact of field application of liquid mink manure on Fannia canicularis L. (Fannidae, Diptera) population in Cavendish, NL

Abstract

The Cavendish mink fur producer was blamed by area residents for causing a severe annoyance of lesser housefly (Fannia canicularis L). To address the problem, the farm had installed a mechanized liquid mink manure production system in 2014 which significantly lowered the number of flies. The community’s concern then shifted to the application of the resulting liquid manure to fertilize fields to grow grass (mink bedding). The aim of this project includes assessments of the attraction of F. canicularis to a liquid manure applied field. I explored two hypotheses: i) does liquid manure attract F. canicularis to the field, and ii) does liquid manure enable these flies to breed in the field? A demonstration strip plot in which fly populations were assessed using initially yellow (in 2015), and, thereafter in 2016 with yellow, blue and transparent sticky cards. SLAM traps were deployed throughout both sampling seasons. Soil samples were surveyed for evidence of F. canicularis breeding. Only 22 F. canicularis were trapped in sticky cards during 2015 and zero in 2016. In SLAM traps only two in 2015 with none captured in 2016. There was no evidence of breeding in the manure-treated field. This near absence in 2015 and complete absence in 2016 negated a need for statistical analyses or further assessments of F. canicularis activity using a more powerful experimental design. However, a de novo technique was introduced in chapter 3: stratification of strips via Autocorrelation function which permitted the development of a rigid statistical model to analyze the treatment effects on frequently captured flies during seven sampling periods in 2015. Results showed significant interaction effects among treatments and sampling periods for overall flies, Anthomyiidae and Muscidae. For Fannidae, the interaction effect was not significant whereas treatment effects were. Overall fly numbers especially Anthomyiidae increased after liquid manure application, with declining abundance thereafter. However, in conclusion, liquid mink manure will be safe for field application neither will be an issue in breeding or attracting F. canicularis nor any other group of flies.