Journal of Mosquito Research 2015, Vol.5, No.19, 1-7
2
English it is called custard apple and in Telugu it is
called Ramphalam. It was reported that ethanol extract
of leaf and stem of this plant has anticancerous
properties. It is traditionally used for curing several
diseases such as cardiac problems, worm infestation,
dysuria, epilepsy, antifertility, dysentery, etc. (Kaleem
et al., 2006; Suresh et al., 2006; Raj Sobiya et al.,
2009).
2 Result
Table 1 and Table 2 depict the mortality percentages
of all instars larvae (1
st
- 4
th
) of
Ae. aegypti
and
Cx.
quinquefasciatus
at different concentrations respectively
after 24, 48 and 72 h of exposure periods. From Table 1
and Table 2, it was observed that mortality percent
increased with increase in concentrations and time of
exposure. 1
st
instar larvae of
Cx. quinquefasciatus
were
more susceptible than 2
nd
, 3
rd
and 4
th
instars larvae.
LC
50
, LC
90
values (95% confidence level),
regression
equations of ethanol leaf extract of the plant against 1
st
- 4
th
instars larvae of
Ae. aegypti
and
Cx. quinquefasciatus
after 24, 48 and 72 h of exposure are presented in Table
3 and 4. From Table 3 and 4, it was observed that LC
50
and LC
90
values
gradually decreased with period of
exposures in different larval forms of
Ae. aegypti
and
Cx. quinquefasciatus
. There was a strong correlation
between concentrations of the extract and mortality
percentages as R
2
(co efficient of determination)
values were close to 1 in all cases. Three ways
factorial ANOVA established statistical significance of
larval mortality of
Ae. aegypti and Cx. quinquefasciatus
(p<0.05) in terms of instars, times and concentrations
(Table 5 and 6). In case of tested non-target aquatic
organisms, no mortality and abnormal behaviour were
noticed upto 72 h of exposure period. No mortality
was observed on control treatments of non-target
organisms.
3 Discussion
Phytochemicals are suitable alternatives to chemical
insecticides as their use in environment is relatively
safer and such plants are available in many parts of
the world (Bowers et al., 1995). Various parts of the
plants have been reported by researchers for their
larvicidal potency against different species of
mosquitoes (Chowdhury et al., 2007, 2008; Hossain
et
al., 2011; Singha and Chandra, 2011; Mallick Halder
et al., 2011; Adhikari et al., 2012; Mallick
et al., 2014;
Singha Ray
et al., 2014; Singh
et al., 2015; Mallick
and Chandra, 2015).The present study indicates that
larvae of
Cx. quinquefasciatus
were more susceptible
to ethanolic leaf extract of
A. reticulata
as compared
to
Ae. aegypti
. Nayak, (2014) reported the larvicidal
activity of methanol leaf extract of
A. reticulata
against early 4
th
instar larvae of
Cx.quinquefasciatus
while Mallick et al., (2015) reported the larvicidal
activity of acetone leaf extract of
A. reticulata
against
1
st
to
4
th
instars larvae of
Ae. aegypti
,
Anopheles
stephensi
and
Cx. quinquefasciatus
. Mallick and
Chandra, (2015) reported the larvicidal activity of
extracts of stem bark of
A. reticulata
against
Cx.
quinquefasciatus
mosquito. Mallick and Chandra,
(2015) also reported the larvicidal potential of root
extracts of
A. reticulata
against
Cx. quinquefasciatus
Singha et al., (2011) worked with petroleum ether,
chloroform::methanol (1:1 v/v) and ethyl acetate
extracts of mature leaves of
Mesua ferra
L. against 3
rd
instar larvae of
Cx.quinquefasciatus
having LC
50
values 195.33, 27.28, 74.19 ppm respectively after 48
h of exposure. However,
in this study, ethanol leaf
extract of
A. reticulata
shows a remarkably low LC
50
value (1.728 ppm) against 3
rd
instar larvae of
Cx.
quinquefasciatus
after 48 h of exposure. Manzoor
et
al
., (2013) reported the larvicidal activity of essential
oil from
Ocinum calamus
, against 3
rd
instar larvae of
Ae. aegypti
and
Cx. quinquefasciatus
after 24 h of
exposure having LC
50
values 75.35 and 92.30 ppm
respectively. In comparison, ethanol leaf extract of
A.
reticulata
recorded very low LC
50
values (14.57 and
4.2048 ppm) against 3
rd
instar larvae of
Ae. aegypti
and
Cx. quinquefasciatus
respectively after 24 h of
exposure. Singh
et al., (2006) reported that LC
50
values of hexane extract of
Momordica charantia
against 4
th
instar larvae of
An. stephensi,
Cx.
quinquefasciatus
and
Ae. aegypti
were 66.05, 96.11
and 122.45 ppm respectively
after 24 h of exposure.
However, present study shows LC
50
values of ethanol
leaf extract of
A. reticulata
as 6.22 and 19.88 ppm
against 4
th
instar larvae of
Cx. quinquefasciatus
and
Ae. aegypti
respectively after 24 h of exposure which
are much lower values than other plants. Maheswaran
et al., (2008) reported highest larvicidal activity of the
hexane extract followed by chloroform and ethanol
extracts of
Leucus aspara
leaves against
Cx.
quinquefasciatus
and
Ae. aegypti.
The LC
50
values of
hexane extract of leaves of
Leucus aspara
against 1
st _
4
th
instar larvae of
Cx. quinquefasciatus
were 122.50,
