International Journal of Horticulture, 2017, Vol.7, No. 9, 64-75
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2.5 Correlation between mortality and oviposition as well as between adult emergence and weight loss
The correlation between adult mortality at 96 h post treatment and oviposition as well as adult emergence and
weight loss of the protected cowpea seed were presented in Table 4 and Table 5 respectively. The R values of the
regression that tend to 1 reflected high correlation between the mortality of the insect and the oviposition rate.
However, hot water extract of the nut recorded the highest R value of (0.982). Also, the R
2
value of the hot extract
of the nut showed that only 96.4% of the oviposition rate of the insect are being determined by the mortality of the
insect. Nevertheless, after the adjustment of the value only 96.1% of the oviposition can be explained by the insect
mortality. The t-value of -18.675 of the hot water extract of the nut that was more negative than -1.98 indicated
that there was a great statistically significant relationship between the mortality and oviposition. Irrespective of
the plant part used, all the extracts of
A. occidentale
recorded statistically significant relationship between the
insect mortality and oviposition at F=261.987, df =1, 13, p < 0.0001 (NC); F=236.372, df =1, 13, p < 0.0001 (SC);
F= 109.123, df =1, 13, p < 0.0001 (RC); F= 67.562, df =1, 13, p < 0.0001 (LC); F= 348.742, df =1, 13, p < 0.0001
(NH); F=150.433, df =1, 13, p < 0.0001 (SH); F=103.689, df =1, 13, p < 0.0001 (RH); F=90.381, df =1, 13, p <
0.0001 (LH); F=301.730, df =1, 13, p < 0.0001 (NE); F=258.375, df =1, 13, p < 0.0001 (SE); F=270.390, df =1,
13, p < 0.0001 (RE) and F=48.275, df =1, 13, p < 0.0001 (LE). In addition, the F-value of the Nut extracted with
water showed that it recorded the highest relationship between the insect mortality and the oviposition. There was
a great relationship between the adult emergence of the insect and the weight loss of the protected cowpea grains
as reflected by their R value which tends to 1. However, the nut extracts of the plant recorded the highest R value
(0.999) regardless of the extraction method used. Also, The R
2
value of the nut extracts showed that adult
emergence of the beetle was responsible for 99.8% of the seed weight loss of the cowpea even after adjustment.
The t-values of the regression that were greater than 1.98 showed that there was correlation between the adult
emergence of the beetle and the weight loss of the cowpea with the nut extracts recorded the highest t-value
(87.847). Regardless of the plant part used, all the extracts of
A. occidentale
recorded statistically significant
relationship between the adult emergence of the insect and weight loss of the cowpea at
F=7717.107, df =1, 13, p
< 0.0001 (NC); F=1024.332, df =1, 13, p < 0.0001 (SC); F= 1091.932, df =1, 13, p < 0.0001 (RC); F= 712.071, df
=1, 13, p < 0.0001 (LC); F= 7717.107, df =1, 13, p < 0.0001 (NH); F=3072.066, df =1, 13, p < 0.0001 (SH);
F=2598.284, df =1, 13, p < 0.0001 (RH); F=5250.411, df =1, 13, p < 0.0001 (LH); F=7717.107, df =1, 13, p <
0.0001 (NE); F=302.003, df =1, 13, p < 0.0001 (SE); F=195.893, df =1, 13, p < 0.0001 (RE) and F=248.729, df
=1, 13, p < 0.0001 (LE). In addition, the F-value of the Nut extracts showed that it recorded the highest
relationship between the adult emergence and the seed weight loss.
Table 4 Correlation between insect mortality and oviposition of
C. maculatus
exposed to
A. occidentale
extract
Plant
parts
Extraction
methods
R
R
2
Ad (R
2
)
K ±S.E
R
c
±S.E
R
E
t-value
Sig.
Nut
Cold
Hot
Ethanol
0.976
a
0.982
0.979
0.953
0.964
0.959
0.949
0.961
0.956
24.88 ±0.82
24.28±0.49
24.03 ±0.77
-0.21 ±0.01
-0.14±0.01
-0.18±0.01
O=24.88-0.21(M)
O=24.28-0.14(M)
O=24.03-0.18(M)
-16.186
-18.675
-17.370
0.0001
0.0001
0.0001
Stem
bark
Cold
Hot
Ethanol
0.974
0.959
0.976
0.948
.920
.952
0.944
.914
.948
24.22 ±0.70
24.41 ±0.70
24.15 ±0.82
-0.18 ±0.01
-0.15 ±0.01
-0.18 ±0.01
O=24.22-0.18(M)
O=24.41-0.15(M)
O=24.15-0.18(M)
-15.374
-12.265
-16.074
0.0001
0.0001
0.0001
Root bark Cold
Hot
Ethanol
0.945
0.943
0.977
0.894
0.889
0.954
0.885
0.880
0.951
24.28 ±0.83
24.38 ±0.78
24.52 ±0.86
-0.16 ±0.02
-0.14 ±0.01
-0.23 ±0.01
O=24.28-0.16(M)
O=24.38-0.14(M)
O=24.52-0.23(M)
-10.446
-10.183
-16.444
0.0001
0.0001
0.0001
Leaf bark Cold
Hot
Ethanol
0.916
0.935
0.888
0.839
0.874
0.788
0.826
0.865
0.772
25.03 ±1.27
24.20 ±0.64
23.10 ±1.53
-0.21 ±0.03
-0.12 ±0.01
-0.18 ±0.03
O=25.03-0.21(M)
O=24.20-0.12(M)
O=23.10-0.18(M)
-8.220
-9.507
-6.948
0.0001
0.0001
0.0001
Note: Ad (R
2
): adjusted R
2
value; K: constant; S.E: standard error; R
c
: regression coefficient; R
E
: regression equation
