Page 12 - Volume 4, Issue 2, July 2011
Basic HTML Version
© Benaki Phytopathological Institute
Michaelakis
et al.
40
for EOpip and EOpul1 respectively).
Discussion
In this study, essential oils of
Mentha
spe-
cies and their major ingredients were tested
with respect to their larvicidal effect against
Cx. pipiens
mosquitoes. The selection of the
three
Mentha
species,
M. pulegium
(three
populations),
M. piperita
and
M. spicata
, was
based on obtaining essential oils that pos-
sessed different chemical profiles. The iso-
lated essential oils can be characterized as
pulegone type (EOpul1), piperitone type
(EOpul2), piperitone-isomenthone type
(EOpul3), menthone-menthol type (EOpip)
and carvone type (EOsp). These results of
Table 2.
LC
50
and LC
90
values for essential oils and their isolated major components against
larvae of
Culex pipiens
biotype
molestus
. Major components percentage composition, in re-
lation to their precursor essential oils, is also given in parenthesis.
Essential oil / Major components
(% composition in essential oil)
n
c
Slope (±SE)
LC
50
(95% CL)
a
LC
90
(95% CL)
a
χ
2
df
EOpul1
400 4.93±0.53
46.97
(43.92-50.73)
85.42
(74.51-104.51)
15.440 18
pulegone (61.1%)
400 4.87±0.52
27.23
(24.39-29.7)
49.91
(45.4-56.61)
12.402 15
piperitenone (4.0%)
320 5.16±0.55
75.91
(72.54-79.2)
97.31
(92.16-104.84)
5.909 10
EOpul2
480 8.84±0.94
168.59
(157.76-182.99)
235.44
(209.67-293.82) 37.275
b
16
Piperitone (92.6%)
320 8.47±0.9
131.91
(112.92-155.81)
186.84
(157.64-287.79) 47.024
b
10
EOpul3
320
––
>200
––
–– ––
piperitone (69.3%)
400 8.32±0.83
129.51
(118.78-142.17)
178.98
(159.16-223.33) 35.466
b
13
isomenthone (24.8%)
320
––
> 200
––
–– ––
EOsp
320 10.66±1.19
95.9
(80.44-107.13)
126.46
(112.57-162.87) 43.362
b
10
carvone (71.8%)
400 5.54±0.68
95.31
(84.58-106.77)
162.31
(137.02-228.97) 26.735 13
EOpip
480 22.29±0.22
40.28
(30.9-50.56)
146.17
(105.4-252.54) 44.197
b
19
menthone (39.0%)
480 9.29±0.92
111.11
(104.54-116.67)
152.63
(145.23-162.51) 18.942 16
menthol (25.9%)
400 8.6±1.31
120.97
(105.35-130.02)
170.45
(157.72-199.31) 20.977 13
a
LC values are expressed in mgl
-1
and they are considered significantly different when 95% CL fail to overlap.
b
Since goodness–of–fit test is significant (P<0.05), a heterogeneity factor is used in the calculation of confidence
limits (CL).
c
Total number of larvae tested.
