Abstract:
Culicoides midges (Diptera: Ceratopogonidae), are involved in the transmission of various
pathogens that cause important diseases of livestock worldwide. The use of insect repellents
to reduce the attack rate of these insects on livestock could play an important role as part of
an integrated control programme against diseases transmitted by these midges. The objective
of this study was to determine whether high frequency sound has any repellent effect on
Culicoides midges. The number of midges collected with 220 V Onderstepoort white light
traps fitted with electronic mosquito repellents (EMRs), emitting 5-20 KHz multi-frequency
sound waves, was compared with that of two untreated traps. Treatments were rotated in two
replicates of a 4 x 4 randomised Latin square design. Although fewer midges were collected
in the two traps fitted with EMRs, the average number collected over eight consecutive nights
was not significantly different. The EMRs also had no influence on any of the physiological
groups of Culicoides imicola Kieffer or the species composition of the Culicoides population as
determined with light traps. The results indicate that high frequency sound has no repellent
effect on Culicoides midges. There is therefore no evidence to support their promotion or use
in the protection of animals against pathogens transmitted by Culicoides midges.
Description:
G.J.V. (Agricultural Research Council – Onderstepoort
Veterinary Institute) was the project leader and was responsible for the project design. S.N.B.B. (Agricultural
Research Council – Onderstepoort Veterinary Institute) was
responsible for the collection of the Culicoides midges and
the rotation of the light traps. K.L. (Agricultural Research
Council – Onderstepoort Veterinary Institute) did all the
Culicoides species analyses and age grading of the collections.
L.M. (ARC-Biometry Unit) was responsible for most of the
statistical analyses. G.J.V. (Agricultural Research Council –
Onderstepoort Veterinary Institute) wrote the manuscript.
