Transcript right slide dm

Discussion
•Differences and similarities between the
experiments done by Chigwaza Et. Al (2004) can be
observed
•Similarities between the experiments are the same
base ingredients in the solutions were used, lippia
and tagetes leaves
•Differences include different proportions, the
solutions used in this experiment were cut down to
¼ of what Chigwaza used, different plants
(Chigwaza used cabbage), different types of aphids
(Brevicoryne Brassica vs. Acyrthosiphon pisum) and
different results
The above image is a simulated habitat for aphids
or “bug rearing cage”. Inside it contains pea
plants that are watered twice weekly. The top of
the cage is covered with a fine mesh to prevent
aphid escape and to still let air in. The cage can
hold a couple thousand aphids at a time. (taken
by author)
•Although in both experiments, this one and
Chigwaza’s, both solutions did kill aphids, the
percentage of aphids killed in Chigwaza’s
experiment were significantly less than in this one. In
this experiment 100% of the aphids were killed in
testing by both solutions, and in Chigwaza’s 8.75%
were killed by tagetes and about 50% were killed by
the lippia javanica solution
•A significant difference that contradicts with
Chigwaza’s conclusions and results is that in this
experiment the tagetes solution did a better job of
reducing aphid population than the lippia, whereas in
Chigwaza’s experiment the results were the opposite
of this.
•These discrepancies can allude to unforeseen
variables affecting the experiment, or the differences
could be a problem in the difference between the
number of experiments run by Chigwaza and the
number of experiments run in this project.
Graphed results for Chigwaza’s experiment
results, Effectiveness of Natural Herbs,
Fever Tea (Lippia javanica) and
Mexican Marigold (Tagetes minuta) as
Substitues to Synthetic
Pesticides in Controlling Aphid Species
(Brevicoryne brassica) on
Cabbage (Brassica capitata).
(http://www.uady.mx/~veterina/publicaciones/journal/Revista/2004-3/katsvanga-36.pdf)
Conclusion
•The experiment showed that both the
Lippia Javanica and Tagetes Minuta
liquid solutions were effective in killing
aphids and reducing their population
•Both solutions killed 100% of the
aphids exposed to them, and it was
seen that the tagetes solution killed the
aphids quicker than the lippia solution
by 31.4 seconds
Future Studies
•In future studies I may be
experimenting with the natural flower
pyrethrum which also has insecticidal
properties, or increasing the efficacy of
Lippia Javanica and Tagetes Minuta by
combining them with pyrethrum extract
Selected Bibliography
•S., Chigwaza et al., EFFECTIVENESS OF NATURAL HERBS,
FEVER TEA (Lippia javanica) AND MEXICAN MARIGOLD (Tagetes
minuta) AS SUBSTITUTES TO SYNTHETIC PESTICIDES IN
CONTROLLING APHID SPECIES (Brevicoryne brassica) ON
CABBAGE (Brassica capitata)., Tropical and Subtropical
Agroecosystems, 2004
•JG, Scott et al., Kdr-Type resistance in insects with special
reference to the German cockroach, Blattella germanica, PubMed,
1994
•Soderlund, David, Pyrethroids, knockdown resistance and sodium
channels, Pest Management Science, Volume 64 Number 6, 2008
•Soderlund, David, The Molecular Biology of Knockdown Resistance
to Pyrethroid Insecticides, Insect Biochemistry and Molecular
Biology, Volume 33 Issue 6, 2003
•Chandre, Fabrice et al., Identification and Geographic Distribution of
the ACE-1R Mutation in the Malaria Vector Anopheles gambiae in
South-Western Burkina Faso, West Africa, The American journal of
tropical Medicine and Hygiene, 2008
•Corbel, Vincent et al., COMBINATION OF A NON-PYRETHROID
INSECTICIDE AND A REPELLENT: A NEW APPROACH FOR
CONTROLLING KNOCKDOWN-RESISTANT MOSQUITOES, The
American Journal of Tropical Medicine and Hygiene, 2005
•Aldridge, Susan, Insecticide resistance: from mechanisms to
management, Association of British Science Writers, 1998
Edwards, Owain, New Slant on Aphid Spray resistance, Farming
Ahead, No. 174, 2006
Dissection scope used to
observe aphds in petri dishes
during experimentation and
exposure phases (taken by
author)
•Devonshire, Alan, The evolution of insecticide resistance in the
peach±potato aphid, Myzus persicae, Phil.Trans. R. Soc. Lond. B
(1998)