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Bioactivity of
Acyranthes aspera
(Amaranthaceae) Foliage against the Japanese Encephalitis Vector
Culex vishnui
Group
94
Table 5 Completely randomized three way ANNOVA analysis using concentration (C), hour (H) and instars (I) as three parameters
Source of variation
Sum of squares (SS)
Degree of freedom (df)
Mean of squares (MS)
F value
p-level
Instars (I)
967.35
3
322.45
318.91
0
Hours (H)
374.53
2
187.27
185.21
0
Concentrations(C) (C )
5421.22
4
1355.31
1340.41
0
I × H
42.8
6
7.13
7.05
0
I × C
50.96
12
4.25
4.20
0
H × C
34.34
8
4.30
4.25
0
I × H × C
25.14
24
1.05
1.04
0.43
Within groups
121.33
120
1.01
-
-
Total
7037.75
179
39.32
-
-
study was significantly higher (p < 0.05) at relatively
low concentration (100 ppm) of active fraction. The
larvicidal property of essential oils of
A. aspera
against the early fourth instars were reported against
Aedes aegypti
by Khandagle et al (2011) with the LC
50
and LC
90
values of 761 ppm and 817 ppm respectively
with an exposure period of 24 hours. The LC
50
and
LC
90
value of the 4
th
instars larvae after 24 hours of
post exposure were significantly (p < 0.05) lower in
case of
Cx. vishnui
(Table 4).
In brief, the findings of the current investigation
reveal that the leaf extract of
A. aspera
exhibits
remarkable larvicidal activity against mosquitoes of
Cx. vishnui
group. Further laboratory investigations
are required for illuminating the actual chemical
compound responsible for larvicidal activity. This
activity may again be tested against an extensive range
of mosquito species in field conditions. Further
investigations are also required to identify the
chemical personality of the active ingredient and to
successfully utilize, if possible, by formulating a
commercial product.
3 Material and Methods
3.1 Compilation of plant materials
Fresh foliage of
A. aspera
were collected randomly
during June 2012 from Golapbag Campus, The
University of Burdwan (23°16´N, 87°54´E), West
Bengal, India.
3.2 Rearing the larvae and colony set up
Assorted larvae
Cx. vishnui
group were collected from
inundated rice fields of Agriculture Farm, The
University of Burdwan (
23°16´N, 87°54´E)
through
standard scooping and dipping method (
Robert et al.,
2002
) to build up the colony. The larvae were housed
in plastic trays filled with tap water and periodically
fed with a mixture of Brewer yeast, dog biscuits and
algae in 3:1:1 ratio (Kamaraj et al., 2011). Pupae were
relocated from the trays to insectary (45×45×40 cm)
where adults came out. In glass cages adults were
nurtured and provided with 10% sucrose solution with
multivitamin syrup in a container with a cotton wick.
The mosquitoes were identified based on the key
provided by Barraud (1934), Christophers (1933) and
Chandra G. (2000). The adults of
Cx. vishnui
group
were reared selectively in a different glass cage where,
on the 5
th
day of rearing, adults (females) were given a
blood meal from a non-motile shaved pigeon
overnight. Petri dishes filled with 100 ml of tap water
and wrinkled with filter paper were kept inside the
cage for oviposition. The eggs were unruffled and
allowed to hatch under laboratory conditions. The
processes were repeated to set up a laboratory reared
colony of
Cx. vishnui
group. The colony was
maintained at (27±2)
℃
temperature and 80%~85%
relative humidity (RH) under a 13:11 light-and-dark
cycles.
3.3 Crude extract procurements
Fresh and young green leaves of
A. aspera
were rinsed
in tap water followed by distilled water and soaked on
a paper towel. Then the unsoiled and unspotted leaves
were pulverized by mechanical grinder and the liquid
was filtered by Whatman’s no-1 filter paper. The
filtrate was regarded as a stock solution (100%
Journal of Mosquito Research