Journal of Mosquito Research 2015, Vol.5, No.10, 1-7
2
has been reported (Mallick et al., 2015). Larvicidal
activities of stem bark extracts of
A. reticulata
against
Cx. quinquefasciatus
has also been reported recently
(Mallick and Chandra, 2015). Root extracts of
A.
reticulata
has been exploited for the first time to kill
Cx. quinquefasciatus
larvae during the present piece
of work.
A. reticulata
is commonly named as Bullock’s Heart,
Ramphal, Sitaphala, Sarifa, and Custard Apple and the
plant is found all over India. Leaves are used as
antihelminthic, styptic, insecticides etc. Bark of
the plant is used as antidysentric and vermifuge
(Ranjini and Jothi Nisha, 2013; Zaman and Pathak,
2013). Ethanol root extract of
A. reticulata
showed
distinct inhibitory effect against human cancer cell
lines at the dose range of 10-40 μg/ml but aqueous
extract exhibited lower activity at same doses (Suresh et
al., 2011).
1 Results
Mortality percent increased with increase in
concentrations and time of exposure of the crude root
extract of the plant. No mortality were noticed on
negative control treatments (Table 1). Table 2 depicts
the mortality percent of 3
rd
instar larvae of
Cx.
quinquefasciatus
at
different concentrations of
petroleum
ether, hexane, and ethyl acetate solvent root extracts
of the plant. Among petroleum ether, hexane, and
ethyl acetate root extracts of the plant, ethyl acetate
root extract showed best larvicidal activity. No
mortality were observed on ethanol treated control
experiments. LC
50
and LC
90
values were lowest in case
of ethyl acetate root extract of the plant than
petroleum ether, and hexane root extracts after 24, 48,
and 72 h of exposures (Table 3). Mortality percent
for 1
st
- 4
th
instars larvae of
Cx. quinquefasciatus
at
different concentrations of ethyl acetate root extract
of the plant was presented in Table 4. 1
st
instar larvae
were most susceptible to ethyl acetate root extract.
Only at 1 ppm concentration 100% mortality was
observed after 48 h of exposure against 1
st
instar
larvae . 2
nd
and 3
rd
instars larvae showed 100%
mortality at 1 and 2 ppm concentrations after 72
and 48 h of post exposure respectively. But no
mortality were noticed on ethanol treated control
experiments. Table 5 and table 6 represented the
LC
50
and LC
90
values, regression equations, R
2
(co
efficient of determination) values of crude and ethyl
acetate root extracts respectively. LC
50
and LC
90
values gradually decreased with time of exposure.
values of R
2
were close to one in all most all cases
indicating a positive corelation between concentration
of the extracts and mortality percent. No mortality
and abnormal behaviour were observed on non target
Table 1 Mortality percent of different instars of
Culex quinquefasciatus
exposed to different concentrations of crude root extract of
Annona reticulata
(Mean mortality percent ±Standard error)
Instars
Concentrations (%)
Mortality % at different exposure periods
24 h
48 h
72 h
1
st
0.01
73.33±3.33
76.66±3.33
90.00±00.00
0.02
76.66±3.33
93.33±3.33
100.00±00.00
0.03
100.00±00.00
100.00±00.00
100.00±00.00
0.04
100.00±00.00
100.00±00.00
100.00±00.00
0.05
100.00±00.00
100.00±00.00
100.00±00.00
2
nd
0.01
33.33±3.33
36.66±3.33
43.33±3.33
0.02
46.66±3.33
53.33±3.33
63.33±3.33
0.03
56.66±3.33
63.33±6.66
76.66±3.33
0.04
66.66±3.33
73.33±3.33
83.33±3.33
0.05
83.33±3.33
86.66±3.33
100.00±00.00
3
rd
0.01
36.66±.33
43.33±3.33
50.00±5.78
0.02
43.33±3.33
46.66±3.33
60.00±5.78
0.03
63.33±3.33
66.66±3.33
76.66±3.33
0.04
66.66±3.33
73.33±3.33
80.00±00.00
0.05
83.33±3.33
83.33±3.33
93.33±3.33
4
th
0.01
26.66±3.33
33.33±3.33
36.66±3.33
0.02
33.33±3.33
40.00±00.00
43.33±3.33
0.03
43.33±3.33
46.66±3.33
56.66±3.33
0.04
53.33±3.33
56.66±3.33
60.00±00.00
0.05
60.00±00.00
66.66±3.33
76.66±3.33
