Biology Reference
In-Depth Information
Table 15.10.
Results obtained in tests with not-choice measured in mortality percentage of
S. frugiperda,
T. molitor
and
D. melanogaster
larvae, after application of the extracts at different concentrations in the
larvae's diet.
D. mela-
nogaster
(% mortality)
LD
50
D. mela-
nogaster
Concentration
(ppm)
S. frugiperda
(% mortality)
T. molitor
(% mortality)
LD
50
S. frugiperda
LD
50
T. molitor
Sample
Control
0
0
0.0
Aqueous
10
0
0
0.0
n.d.
n.d.
n.d.
25
0
0
0.0
50
0
0
0.0
100
0
0
0.0
Ethyl
acetate
10
70 ± 0.6b
45 ± 0.6b
61.0 ± 0.6a
9.4
14.2
7.65
25
55 ± 0.7b
70 ± 0.7b
90.0 ± 0.6b
50
100 ± 0.8c
83.4 ± 0.8c
100.0 ± 1.0c
100
100 ± 1.0c
100 ± 1.0c
100.0 ± 1.0c
Hexane
10
80 ± 0.2b
73.5 ± 0.3d
94.5 ± 0.6a
3.89
5.2
3.23
25
90 ± 0.9c
84.7 ± 0.5b
100 ± 0.6a
50
100 ± 1.0c
95 ± 0.6b
100 ± 0.6b
100
100 ± 1.0c
100 ± 1.0c
100.0 ± 1.0c
Methanol
10
70 ± 0.5b
40 ± 0.7b
30.0 ± 1.52
9.7
20.4
17.9
25
50 ± 0.7b
55 ± 0.7b
65.0 ± 3.4b
50
100 ± 1.0c
80 ± 0.5b
100.0 ± 4.47c
100
100 ± 1.0c
100 ± 1.0c
100.0 ± 4.47c
Me-Ced
10
54.0 ± 0.4d
25 ± 0.9a
70 ± 0.6a
48.0
a
25
79.0 ± 0.3b
49 ± 0.8d
100 ± 1.0c
50
99.0 ± 0.9c
88 ± 0.7c
100 ± 1.0c
Gedunin
10
37.0 ± 0.2a
22 ± 0.8a
69 ± 0.6a
10.8
a
25
45.5 ± 0.3d
59 ± 0.9d
100 ± 1.0c
50
73.5 ± 0.6b
89 ± 0.4c
100 ± 1.0c
Each value corresponds to the average of the five different experiments ± SE. The values followed by the same letter
are not significantly different. The significance level is
p
<95%. The time for
S. frugiperda
was 21 days, for
T. molitor
was
25 days and for
D. melanogaster
was 72 h.
a
This value corresponds to LD
95
(Céspedes
et al.
, 2005)
inhibited each larval growth stage, e.g. growth
and weight gained (up to 75 % of length)
when incorporated into diets (Table 15.11).
Moreover,
n-
hexane extract produced the
strongest inhibition (58.5% and 39.6% at
10.0 and 25.0 ppm, respectively) of growth
and weight increase at 21 days (Table 15.11).
On the other hand, the three extracts
(
n
-hexane, ethyl acetate and methanol), above
25.0 ppm, showed a high growth inhibition,
and after 21 days these extracts showed
100% of mortality, respectively (Table 15.11).
The percentage of larvae that reached
pupation decreased drastically with almost
all extracts assayed. Thus,
n-
hexane (10.0 ppm,
22.8%), ethyl acetate (10.0 ppm, 25.7%) and
methanol (10 ppm, 26.3%) extracts showed a
significant delay of pupation (Table 15.11).
Above 50 ppm no larvae survived to pupa-
tion with
n
-hexane, ethyl acetate and metha-
nol extracts (Table 15.11). Delays in time to
pupation (>24 days) for
n
-hexane (>10.0
ppm), ethyl acetate (>15 ppm) and methanol
(>35.0 ppm) were observed (data not shown).
Furthermore, low concentrations of
n-
hexane,
ethyl acetate and methanol extracts of between
2.0 and 10 ppm significantly reduced pupal
weights, with
n
-hexane being the extract that
produced the greatest effect on pupal weights
between 1.0 to 5.0 ppm (data not shown).
The percentage of adults' emergence
from the pupae was also drastically affected
by these substances. The greatest reductions
were shown by
n-
hexane (2.0 and 10 ppm,
91.7%), ethyl acetate (2.0 and 10 ppm, 83.4
and 91.7%, respectively) and methanol
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