Journal of Mosquito Research 2015, Vol.5, No.12, 1-7
2
origin mainly to overcome these adverse effects in
addition to an environment-friendly remedy.
The Plant
Drypetes roxburghii
(Wall.) Hurus. is an
evergreen tree found throughout India and it belongs
to family Euphorbiaceae. It is generally upto 20 m in
height, branches are usually pendent, and leaves are
simple, alternate. Fruits are drupe type, ovoid-ellipsoid,
seed normally one. Fruits have been used for many
conventional medical applications such as treatment
of ulcers of the mouth, stomach, hot swellings, small
pox and also useful in burning sensation, ophthalmopathy,
hyperdipsia, elephantiasis, constipation, strangury,
azoospermia, habitual abortion, sterility (Sengupta et
al., 1968, Varshney et al., 1973).
Though mosquito larvicidal studies with different
plant extracts are prevalent in a vast volume of
literature (Rawani et al., 2009; Mallick Haldar et al.,
2012, 2013, 2014; Hossain et al., 2011; Kundu et al.,
2013; Singha et al., 2011,2012; Bhattacharya et al.,
2014; Singha Ray et al., 2014), similar reports on
adult mosquito is substantially rare. In the present
study, we reported for the first time the effect of crude
and ethyl acetate extracts of mature fruits of
D.
roxburghii
against adult
Cx. quinquefasciatus
Say and
An. stephensi
Liston. Adulticidal bioassay was performed
to assess the efficacy of the extracts in causing
mortality to adult mosquitoes in laboratory condition.
To test the ability of the extracts to keep away mosquitoes,
repellency test was conducted.
2 Results
Table 1 depicts adulticidal activity of fruit extract of
D.
roxburghii
on
Cx. quinquefasciatus
and
An. stephensi
.
In both the cases the mortality rate increased gradually
with increased concentrations of ethyl acetate extract.
LC
50
and LC
90
values suggested distinctly that adults
of
An. stephensi
were more susceptible to death than
Cx. quinquefasciatus
. The higher R
2
values (near 1) in
both the cases proved the significance of the tests.
Crude extract of fruit also exerted some deleterious
effect on both the species of mosquitoes.
Table 2 Embodies the results of repellency activity of
D. roxburghii
fruits in crude form (fruit juice) as well
as in the form of ethyl acetate solvent extract of the
same against the biting activity of
Cx. quinquefasciatus
and
An. stephensi
. The crude juice was used without
any alteration whereas graded concentrations of the
solvent extract were made for repellency test. The
result reflected that the crude juice was hundred
percent efficient against biting activity of
Cx.
quinquefasciatus
up to 1 hour, but after that its efficiency
slowly decreased and at the end of 150 minutes it
became 73.33%. 1% ethyl acetate extract showed 5%
repellency at 30 minutes of application but after 120
minutes its repellency became nil. 25% extract gave
about 80% protection up to 30 minutes. Among the
other concentrations while 50% concentration gave
100% protection up to 1hour, 75% and 99 %
concentrations conferred hundred percent protections
up to 90 minutes and 2 hours respectively. 94.33 %
Table 1 Adulticidal activity of fruit extracts of
Drypetes roxburghii
on
Culex quinquefasciatus
and
Anopheles stephensi
Type of
Mosquito
Type of
extract
Concentration
(ppm)
Mortality(%)
±SE
LC
50
Value
(ppm)
LC
90
Value
(ppm)
Regression
equation
R
2
value
Cx. Quinquefa-
sciatus
Ethyl acetate
50
7.6 ±0.33 109.62
189.01
Y=-11.85X + 0.49 0.96
100
31.6 ±0.88
150
77.33 ±0.66
200
92.00 ±0.57
250
100.00 ±0.00
Crude
Fruit juice (100%)
28.87 ±1.67 --
--
--
--
An. stephensi
Ethyl acetate
50
15.66 ±0.33 95.41
181.96
Y= 0.39X + 0.44 0.97
100
46.33 ±0.66
150
72.33 ±1.45
200
97.66 ±0.33
250
100.00 ±0.00
Crude
Fruit juice
(100%)
37.67 ±2.12 --
--
--
--
