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Larvicidal and Pupicidal Activities of
P. glandulosus
and
C. rigidus
Leaf Essential Oils against Three Mosquito Species
9
Table 4 Mosquito pupicidal activity of
C. rigidus
essential oil against
Ae. aegypti
,
An. gambiae
and
Cx quinquefasciatus
pupae 24 h
post exposure
Targeted Mosquito species
Conc.(ppm)
MM±SD (%)
LC
50
(LCL
-
UCL) (ppm)
LC
90
(LCL
-
UCL) (ppm)
χ
2
25
18.67±4.61
a
50.95
129.91
2.44
50
50.67±4.11
b
(39.70
-
63.19)
(99.42
-
201.06)
100
73.33±5.32
c
200
100.00±0.00
d
Aedes aegypti
300
100.00±0.00
d
F value
140.89***
25
44.00±5.58
a
47.63
389.46
7.38
50
46.67±5.11
a
(
-
)
(
-
)
100
57.33±3.11
a
200
72.00±3.00
b
Anopheles gambiae
300
100.00±0.00
c
F value
31.48***
100
0.00±0.00
a
307.19
503.61
6.30
200
18.67±4.61
b
(189.80
-
437.66)
(378.09
-
821.03)
300
44.00±3.00
c
400
61.33±4.61
d
Culex quinquefasciatus
500
100.00±0.00
e
F value
211.32***
Note: MM±SD (%): Mean of mortality ± standard deviation (%); MM±SD within a column followed by the same letter do not differ
significantly at P= 0.05 (Duncan’s test); ***: p<0.001; LC
50
and LC
90
: Lethal Concentrations to kill 50% and 90% of pupae
respectively; ppm: parts per million; LCL: Lower Confidence Limit; UCL: Upper Confidence Limit; (
-
): no Confidence Limit
estimated; χ2: Chi
-
squared; Number of replicates: 4
Essential oils extracted from plants are biodegradable
with non-residual effects on the biological
environment due to their rapid volatility. Hence, an
attempt was made in the present study to investigate
the larvicidal and pupicidal potentials of two locally
available plants in Cameroon,
P. glandulosus
and
C.
rigidus
in the control of mosquitoes.
Previous works in Cameroon showed the richness of
the two plant materials in volatile constituents
quantitatively and qualitatively (Nukenine et al., 2007;
Goudoum et al., 2012; Praveen et al., 2012). These
phytoconstituents may be responsible for the mosquito
larvicidal and pupicidal potentials claimed in this study.
The characterization of
P. glandulosus
essential oil
showed a high percentage of oxygenated monoterpenes
(58.6% and 84.6% for fresh and dried leaves,
respectively) represented by cis-piperitone oxide
(3.0% and 35.1%), trans-piperitone oxide (0.5% and
12.6%), fenchone (30.8% and 21.6%) and piperitenone
oxide (10.9% and 6.0%). The main monoterpene
hydrocarbons were terpinolene (25.2% and 7.7%),
limonene (3.2% and 1.7%) and myrcene (2.2% and
1.6%). The sesquiterpene derivatives were found in a
very low percentage (<2.5%), represented mainly by
germacrene D (1.4% and 1.0%) (Ngassoum et al.,
2001). In the same vein, the volatile constituents of
the dried powdered leaf essential oil from the same
plant revealed the presence of thymol (3.7%),
terpineolene (8.2%), fenchone (18.3%), piperitone
epoxide (17.7%), piperitone oxide (8.9%), piperitone
(1.2%), diosphenol (2.5%) and cis-piperitone (19.5%)
(Nukenine et al., 2007). Goudoum et al. (2012)
analysis showed 15 compounds with highest rate of
Fenchone (29.8%) and α-terpinolene (28.3%).
Tatsadjieu et al. (2008) found 23 compounds among
which the main constituents were found to be
β-thujone (30.8%), terpinolene (25.2%) and piperitenone
oxide (10.9%). Yaouba et al. (2012) analysis showed
that the main components found in
P. glandulosus
leaves oil were terpinolene (30.8%), fenchone (13.2%),
terpene 4-ol (11%) and piperitenone oxyde (8%).