- 1Department of Paraclinical Sciences, University of Pretoria. Lilian.Mukandiwa@up.ac.za.
Abstract
Clausena anisata is a medicinal plant used traditionally to treat myiasis and as an insect repellent
by various communities. We have previously demonstrated the effects of
C. anisata extracts on blowfly feeding and development in our
laboratory. The impact of C. anisata leaf extracts on populations of
different fly
species on farms in Mpumalanga, South Africa was investigated in this
study under field conditions. Flies were exposed to liver baits treated
with acetone leaf extracts of C. anisata (150 mg/mL). Fly
numbers and composition on two farms, with and without C. anisata
treated liver, were compared during a period of 12 weeks when fly populations were expected to be high. Observations were made on fly
behaviour and development, adult sizes and numbers. The flies exposed
to liver treated with the leaf extract of C. anisata had a decreased
rate of development, prolonged larval period, smaller body sizes and
more sluggish behaviour compared to those subjected to the control
treatment. No significant differences were, however, found between the
numbers and sizes of flies on the treated and on the control farm, which
was most likely due to the limited nature of the baiting programme we
followed. The effects of C. anisata extracts on blowfly behaviour and
development observed in previous laboratory studies were confirmed in
this field evaluation. Although the extracts did not have a significant
effect on the overall population size in this experiment, we believe
that the C. anisata leaf extract could be useful in integrated pest
management based on its effect on larval development. In addition,
species such as Lucilia cuprina and Chrysomya marginalis seemed to have
been repelled by the C. anisata treated liver; as a result, further work
should explore this aspect and how it can be used for the protection of
animals.
