Comparison of blue cotton and blue polyester fabrics to attract hematophagous flies in cattle farms in Thailand

New materials for improving catches of horseflies (Diptera: Tabanidae) in Nzi traps

New materials in 85 configurations were tested relative to standard fabric Nzi traps to improve catches of tabanids based on artificial visual cues that mimic those used in nature for locating hosts or water. Colour-fast synthetic fabrics and photo-selective horticultural mesh were tested to facilitate insecticide impregnation and for improved durability. Many plastics were explored to document how flies react to polarized and visible vs. ultraviolet light. Lastly, sticky horizontal, linearly polarizing ground-level shiny plastic targets were tested for capturing water-seeking tabanids relative to traps and vertical fabric targets. Based on the capture of 281 786 female Tabanidae (Tabanus Linnaeus, Hybomitra Enderlein, Chrysops Meigen), four alternative formats provided higher catches and/or durability. They were substituting: (1) phthalogen turquoise for phthalogen blue, (2) solution-dyed fabrics for blue and black cotton, (3) clear/white horticultural mesh for mosquito netting, and (4) clear, reflective plastic for some or all netting. A Sunbrella/BioNet fabric trap (portable) and a blue-black Plexiglas®/netting trap (fixed applications) consistently performed best (1.5-3 × higher catches). Ground-level targets captured many male and gravid female Hybomitra but were ineffective for Tabanus. Traps and vertical fabric or transparent sticky targets captured mainly unfed females.

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

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.