Attractiveness and Specificity of Different Polyethylene Blue Screens on Stomoxys calcitrans (Diptera: Muscidae)

Abstract

Stomoxys calcitrans is considered as a major pest of livestock worldwide. Insecticides have been extensively used to control this pest but resistance to these chemical compounds is now reported in many countries. Therefore, a more sustainable and efficient control is needed. Seven different types of blue screens, with reflectances around 460 nm, were tested during summer 2016 in southwestern France to evaluate their attractiveness and their specificity for stable flies. Height of the screen and orientation (east or west) of a blue screen were also considered. High levels of S. calcitrans captures were recorded during this study (from 141 to 7301 individuals per blue screen and per day) whereas the numbers of tabanids and pollinator insects remained extremely low (less than 10 individuals per screen and per day). No significant difference in attractiveness has been shown between the different types of blue screens. The lower half of the blue screens caught significantly more stable flies (70%) than the higher half (30%). The "east" side of the screen attracted 60% of stable flies but this was not significantly different from the west side. These results are highlighting the interest in these blue polyethylene screens for controlling stable flies in cattle farms, in comparison with more expensive blue fabrics.

Keywords: control; stable fly; trapping; visual target.

Figure 1

Zone of study and traps locations: site 1—horse manure, site 2—horse paddock 1, site 3— horse paddock 2, site 4—sheep paddock (Google map modified).

Figure 2

Metal frame and blue screen; the picture was taken at 16: 30 p.m. i.e., 8 h after the blue screen installation. At the back side: horse and manure.

Figure 3

Proportions of stable flies captured by different blue screens during the experiment 1 (26 July to 12 August). The total numbers of stable flies caught per trap were: 30,476 (KLM2); 34,107 (KLM3); 30,298 (KLM4) and 30,523 (Burma). Inside each «violin plot», the white dot represents the median, the black vertical bar represents the first quartile below, the third quartile above. The lower and upper adjacent values (black line stretched from the bar = whiskers) are defined, respectively, as: the first quartile − 1.5 × interquartile and the third quartile + 1.5 × interquartile. The shape around the outside is the sampling distribution using a kernel estimator (density plot of the variable). When it is large, there are more data at this value. A horizontal grey line at 0.25 has been added.

Figure 4

Proportion of stable flies captured by different blue screens during the experiment 2 (16 August to 5 September). The total numbers of stable flies caught per trap were: 9641 (KLM1); 8356 (Sample 1); 10,592 (Sample 2) and 10,699 (Burma). See Figure 3 for explanations about the violin plots.

Figure 5

Proportion of stable flies captured by location in experiment 1 (A) and in experiment 2 (B). See Figure 3 for explanations about the violin plots.