Acta agriculturae Slovenica, 117/3, 1–9, Ljubljana 2021
doi:10.14720/aas.2021.117.3.1655 Original research article / izvirni znanstveni članek
Effects of Prosopis africana (Guill. & Perr.) Taub. and Ficus mucoso Fi-
calho ethanolic leaves extract in the control of Callosobruchus macula-
tus (Fabricius, 1775) in stored cowpea
Tosin Damilola OJUYEMI
 1
, Robert Omotayo UDDIN II
 1
, Gbonjubola Victoria AWOLOLA
 2
, Suleiman 
MUSTAPHA
 1, 3
 and Abdrahaman Adebowale LAW AL
 1
Received May 11, 2020; accepted September 02, 2021.
Delo je prispelo 11. maja 2020, sprejeto 2. septembra 2021
1 Department of Crop Protection, University of Ilorin, Ilorin, PMB 1515 Ilorin, Nigeria
2 Department of Industrial Chemistry, University of Ilorin, Ilorin, PMB 1515 Ilorin, Nigeria
3 Corresponding author, e-mail: juniorsuleiman78@gmail.com
Effects of Prosopis africana (Guill. & Perr.) Taub. and Ficus 
mucoso Ficalho ethanolic leaves extract in the control of 
Callosobruchus maculatus (Fabricius, 1775) in stored cow-
pea
Abstract: The study investigated the effectiveness of 
Prosopis africana and Ficus mucoso ethanolic leave extract 
in the control of Callosobruchus maculatus infesting cowpea. 
Treatments were applied at different concentrations (10 %, 
30 % , 50 %, and 0 %) on cowpea. Five pairs of newly emerged 
adult C. maculatus were introduced into each treatment. The 
two botanicals were evaluated on the insecticidal effects it 
has on the insect and data were recorded on adult mortal-
ity, oviposition rate, larvae, pupae, and adult emergence, seed 
viability, and phytochemicals present in both botanicals. Re-
sults revealed that both treatments had insecticidal potentials, 
adversely reducing the number of eggs, larvae, and pupae of 
C. maculatus with P . africana having the highest mean mortal-
ity rate at 50 % concentration. Observations further indicated 
that the botanicals had no negative effect on seed viability. 
The phytochemical analysis revealed the presence of some 
bioactive compounds such as terpenoids, flavonoids, alka-
loids, saponin, steroids, and tannin, P. africana mostly rich in 
them than F. mucoso. Though both extracts were effective, P. 
africana performed better in the control of the bruchid beetle 
indicating plausible usefulness in sustainable pest manage-
ment by smallholder farmers and consumers of cowpea in 
environments where the plants are in abundance.
Key words: Callosobruchus maculatus; cowpea; botani-
cals; storage entomology; plant-based insecticide; coleoptera
Učinki etanolnih izvlečkov iz listov vrst Prosopis africana 
(Guill. & Perr.) Taub. in Ficus mucoso Ficalho na uravnava-
nje škodljivca Callosobruchus maculatus (Fabricius, 1775) v 
shranjenem zrnju kitajske vinje
Izvleček: V raziskavi so bili preučevani učinki etanolnih 
izvlečkov iz listov vrst Prosopis africana in Ficus mucoso na 
uravnavanje škodljivca Callosobruchus maculatus v semenu 
kitajske vinje. Obravnavanja so obsegala različne koncentraci-
je izvlečka in sicer 10 %, 30 %, 50 %, in 0 %. Pet parov na novo 
izleglih odraslih osebkov škodljivca je bilo izpostavljenih iz-
vlečkom v vseh obravnavanjih. Insekticidni učinki obeh ra-
stlinskih vrst na hrošča so bili ovrednoteni glede na smrtnost 
odraslih osebkov, velikost ovipozicije, glede vplivov na ličinke 
in bube in izleganje odraslih osebkov. Ovrednoten je bil tudi 
učinek izvlečkov obeh vrst na vitalnost semen vinje in njiho-
va kemična sestava. Izsledki so pokazali, da imata obe rastlin-
ski vrsti insekticidni potencial, ker sta imeli negativni učinek 
na število jajčec, ličink in bub škodljivca, pri čemer je izvleček 
iz vrste P . africana povzročil največjo smrtnost pri 50 % kon-
centraciji. Nadalje so opazovanja pokazala, da izvlečka obeh 
vrst nista imela negativnega učinka na vitalnost shranjenih 
semen vinje. Fitokemična analiza izvlečkov je odkrila priso-
tnost nekaterih bioaktivnih snovi kot so terpenoidi, flavonoi-
di, alkaloidi, saponini, steroidi, in tanini, pri čemer je bila vrsta 
P. africana  bogatejša na njih kot vrsta F. mucoso. Čeprav so 
sta bila oba izvlečka učinkovita, je izvleček iz vrste P . africana 
deloval bolje pri uravnavanju populacije hrošča, kar kaže na 
verjetno koristnost uporabe pri trajnostnem obravnavanju 
škodljivcev pri malih kmetih in potrošnikih kitajske vinje v 
okoljih, kjer sta obe vrsti rastlin v izobilju.
Ključne besede: Callosobruchus maculatus; kitajska vin-
ja; rastlinski pripravki; entomologija shranjevanja pridelkov; 
insekticidi na osnovi rastlin; hrošči

Acta agriculturae Slovenica, 117/3 – 2021 2
T. D. OJUYEMI et al.
1 INTRODUCTION 
Vigna unguiculata (L.) Walp (Cowpea), is an im-
portant legume crop in the tropics, and ensures the pro-
vision of plant-based protein for most people and also 
the fixation of nitrogen into the soils (Umeozor, 2005). 
Production of cowpea is limited by several abiotic and 
biotic factors, both in the field and in storage. Among 
the constraining biotic factors are insect pests (Swella 
& Mushobozy, 2007) mainly due to infestation by the 
cowpea bruchid, Callosobruchus maculatus (Fabricius, 
1775) (Coleoptera: Bruchidae) which is a cosmopolitan 
field-to-store pest, and has been ranked as the principal 
post-harvest pest of cowpea especially in the tropics. 
It causes substantial qualitative and quantitative losses, 
manifested by seed perforation, and reductions in mass, 
market value, and germination ability of seeds. In stor-
age conditions, 100 % infestation of cowpea, occurring 
within 3 to 5 months of storage, is not uncommon (Lale 
& Mustapha, 2000).
Toxic residual insecticides have been used rou-
tinely for many years to control insect pests in stored 
grain. These insecticides are primarily organophospho-
rous and pyrethroid compounds (Arthur, 1996). Sev-
eral methods have also been employed over the years to 
protect cowpea from damages by the pest, using chemi-
cal insecticides which is the most prevalent (Abdullahi 
et al., 2011). However, the use of chemical insecticides 
is fast becoming less desirable because of the resistance 
in major insects, regulatory restrictions on the use of 
insecticides, awareness of environmental pollution, the 
increasing cost of insecticides, erratic supplies, worker’s 
safety and, consumer desire for a pesticide-free prod-
uct, which has led to pest management specialists reap-
praising natural products for potential usage (Haghtal-
ab et al., 2009).
Chemical methods are also directly or indirectly 
dangerous to the user and non-target organisms, de-
struction of beneficial organisms, residual toxicity, 
widespread environmental hazards, development of 
resistance by insect species, etc. are always in associa-
tion with its usage (Oni & Ileke, 2008; Oni, 2011). This 
necessitated the need for a safer alternative and sustain-
able control strategy. It is in this regard that extracts 
of plants have been thought of from different parts of 
the world. The method has been described as a cheaper 
eco-friendly and safer means of controlling insect pests 
of stored cowpea (Adedire et al., 2011). 
Singh and Saratchandra (2005) reported that most 
plant species exhibit insect deterrent ability further in-
dicative of the fact that some plant extracts can inhibit 
normal development in insects. Also, most of these 
plants can be acquired locally and freely and are easy 
to handle by smallholder farmers without any accruing 
adverse effects to man and the environment. In view 
of the increasing economic importance of cowpea and 
the intensity of damages due to insect pest infestation, 
an attempt was made to provide a safer method for 
the control of C. maculatus in stored grains using the 
plant extracts Prosopis africana and Ficus mucoso. Previ-
ously, there have been reports on the effectiveness of 
these plants genus in the control of pests and pathogens 
(Dangarembizi et al., 2012; Elaigwu et al., 2018; Zerihun 
& Ele, 2018; Shinkafi & Abdullahi, 2018) but without 
any scientific study targeted at investigating their po-
tential effectiveness in curtailing the ruthless destruc-
tion by C. maculatus in stored seeds. The plants have 
promising potential to be considered as an alternative 
seed treatment to synthetic insecticides therefore the 
reason why this research work was initiated, to investi-
gate the insecticidal activities of the two botanicals on 
the field-to-store insect pest. Furthermore, this research 
presents the first report on the use of P. africana and 
F. mucoso leave extracts in the control of the infamous 
cowpea weevil- C. maculatus.
2 MATERIALS AND METHODS 
2.1 SOURCE AND TYPE OF SEED
The cowpea seeds used were the variety 
IT99K-573-1-1 which was obtained from the Interna-
tional Institute of Tropical Agriculture (IITA), Ibadan, 
Nigeria. The seeds were white in colour and medium in 
size. The cowpea seeds were stored in the freezer com-
partment of a refrigerator at -17 
o
C for four days before 
the seeds were used for the experiment. 
2.2 INSECT CULTURE
Callosobruchus maculatus used for this study was 
obtained from Nigeria Stored Product Research Insti-
tute (NSPRI), Ilorin Kwara State. The cowpea variety 
IT99K-573-1-1 was used to maintain insect culture by 
placing seeds in a plastic container of medium size to 
culture the insect at room temperature (22 
o
C). Plastic 
containers used for insect culture were covered with 
muslin clothe at the top held with a rubber band to al-
low for ventilation. 

Acta agriculturae Slovenica, 117/3 – 2021 3
Effects of ... ethanolic leaves extract in the control of Callosobruchus maculatus (Fabricius, 1775) in stored cowpea
emerged adults of Callosobruchus maculatus. To prevent 
escape and allow for ventilation, muslin cloth fastened 
with a rubber band were used to cover containers after 
applying the various treatments.
Adult weevil mortality was observed daily for 4 
days at 24, 48, 72, and 96 hours respectively and the 
number of dead weevils was counted and recorded. The 
insects were confirmed dead when there was no re-
sponse to probing with a sharp entomological needle at 
the abdomen. Furthermore, to check for the emergence 
of new generation of the insect after applying the treat-
ment on cowpea, a pointed forceps was used to pick five 
seeds at random from each replicate on the 4
th
, and 7
th
 
day after infestation, and selected seeds were examined 
for eggs after dissection with a sharp blade and the dis-
sected beans were examined for larvae and pupae. The 
pointed forceps were used to prevent damage of the egg 
on the seeds. The emergence of the first filial (F
1
) adult 
generation was also observed from 28 to 32 days after 
infestation. 
Seed viability test was carried out on ten randomly 
selected seeds from each replication with the various 
treatments and concentration levels at the end of the ex-
periment using floatation and germination techniques. 
The floatation method was adopted from the technique 
described by Ehiagbonare and Enabulele (2007). The 
percentage viability of seeds was calculated using the 
following formula: . Here, S = Number of treated seeds 
used per replicate. SF = Number of floating seeds per 
replicate.
The germination method was slightly modified 
from the technique described by Holly (2006). Cowpea 
seeds were placed on a petri dish already layered with 
dampened Whatman filter paper and left at room tem-
perature (26-28 
o
C) for a period of 7 days during which 
time, samples were regularly checked for sprouting, and 
moisture was added to prevent complete dryness of the 
samples. The percentage viability of germinated cow-
pea seeds was recorded using the formula: 
2.7 STATISTICAL ANALYSIS
Data were subjected to two-way analysis of vari-
ance (ANOVA). Where treatment means were signifi-
cant, multiple comparisons of treatments was done 
using the Tukey’s honestly significant difference test at 
5% level of significance. All statistical analysis was done 
using the IBM SPSS version 26.
2.3 COLLECTION AND PREPARATION OF 
PLANT MATERIALS
Africana mesquites (Prosopis africana 
(Guill. & Perr.) Taub.) and Sand paper (Ficus mucoso 
Ficalho) leaves were plucked within University of Ilorin 
premises. Leaves were washed and air-dried for 14 days 
in the open field of the faculty of agronomy pavilion. 
The dried leaves were ground using mortar and pestle 
and then passed through 90-micron mesh sieve to ob-
tain a uniform powder. 
2.4 EXTRACTION OF PLANT MATERIALS
Extraction of each plant material was carried out 
in the laboratory by soaking 500 g of each of the plant 
powder in 2 l of ethanol for 72 hours with occasional 
stirring. The solution of each plant material was filtered 
using Whatman No. 1 filter paper. The extracts were 
concentrated using a rotary evaporator at a maximum 
temperature of 45 
o
C. The resulting crude extract was 
stored in a plastic container at room temperature until 
ready for use.
2.5 METHODS OF PHYTOCHEMICAL SCREEN-
ING
Chemical tests were carried out on the ethanolic 
extracts for the qualitative determination of phyto-
chemical constituents as described by Harborne (1973), 
Trease and Evans (1989), and Sofowora (1993).
2.6 EXPERIMENTAL PROCEDURE
The ethanolic leaf extracts of P. africana and F. 
mucoso were dissolved in distilled water to prepare 
solutions of different concentrations (10, 30, and 50 % 
w/v). 100 g of cowpea seeds were treated with 0.5 ml of 
Prosopis africana and Ficus mucoso ethanolic extract in 
six replicates at different concentrations (10, 30, 50 % 
w/v) in transparent plastic containers (7 × 8 cm) also, 
untreated seeds were included as a control (0 %). The 
plant extract was applied to the seed samples with a 
micro-syringe and was thoroughly mixed with a wood-
en spatula. The seeds were air-dried in the laboratory 
for 5 minutes before introducing five pairs of freshly 

Acta agriculturae Slovenica, 117/3 – 2021 4
T. D. OJUYEMI et al.
3 RESULTS
3.1 EFFECT OF BOTANICAL TYPES ON ADULT 
MORTALITY OF Callosobruchus maculatus
Table 1 shows the effectiveness of the botani-
cal types at different concentrations on the mortality 
of adult C. maculatus. At 24, 48, 72, and 96 hours after 
treatment (HAT) both P . africana and F. mucoso had the 
most significantly highest rate of C. maculatus mortality 
at the concentration level of 50 % when compared to 
the control which had the least. Furthermore, the two 
botanical treatments at 30 % also had effective control 
of the insect pest population from 24 to 96 HAT as pre-
sented in Table 1. The mean number of insect mortality 
at the treatments concentration level of 10 % indicated 
a slower rate of control in comparison to the concentra-
tion levels of 50 and 30 %. 
The overall effects of the different botanical treat-
ment are also indicated in Table 1. At 24, 48 and 72 HAT , 
P . africana had a significantly (p < 0.05) higher mortal-
ity rate of the mean 5.650 ± 0.365, 12.623 ± 0.205 and 
13.359 ± 0.025 respectively when compared to F. mucoso 
which was lower at the mean numbers of 1.541 ± 0.234, 
5.600 ± 0.300 and 10.863 ± 0.044 respectively. However, 
at 96 HAT, the leave extracts of P . africana and F. mucoso 
showed no significant difference of adult mortality of C. 
maculatus thus having the same effective level of con-
trol on the insect pest.
3.2 EFFECT OF THE BOTANICAL TREATMENTS 
ON THE OVIPOSITION, LARVAE AND PU-
PAE EMERGENCE OF C. maculatus
Table 2 presents the activities of the botanical 
treatment in restricting the oviposition, larvae and pu-
pae emergence of the insect pest. Post hoc analysis in-
dicated the two different botanical treatments at 50 % 
concentration to possess the least mean number of eggs 
and also larvae and pupae population. This was fol-
lowed by the concentration rate of 30 % only for seeds 
treated with P. africana. F. mucoso had no significant 
differences with the control at the concentration rate 
of 30 % and 10 % in all the various early life stages in 
Table 2. 
In total, the control had the most numbers of eggs, 
larvae and pupae of the insect pest. There was no sig-
nificant difference in the two botanical treatments in 
the number of eggs laid by the pest. Furthermore, seeds 
that were treated with P. africana had the least larvae 
and pupae emergence compared to F. mucoso and the 
control (Table 2). 
Adult mortality rate (HAT)
Botanical type Concentrations 24 48 72 96
P . africana 10 % 0.000 ± 0.000
c
6.670 ± 1.620
c
13.33 ± 0.590
b
16.670 ± 0.033
b
30 % 10.00 ± 2.000
ab
20.00 ± 3.452
ab
20.00 ± 3.452
a
16.670 ± 0.740
b
50 % 13.331 ± 0.612
a
23.33 ± 4.213
a
20.00 ± 3.562
a
26.67 ± 1.111
a
 
F. mucoso 10 % 0.000 ± 0.000
c
6.670 ± 1.620
c
6.670 ± 1.620
d
16.671 ± 0.323
b
30 % 6.670 ± 1.020
b
16.67 ± 0.321
ab
16.671 ± 0.321
ab
16.671 ± 0.033
b
50 % 13.330 ± 0.723
a
20.000 ± 3.521
ab
20.00 ± 3.510
a
23.33 ± 2.271
ab
Control 0.0 0.000 ± 000
c
0.000 ± 0.000
d
0.000 ± 0.000
e
3.330 ± 1.730
c
Total effect of the botanical treatments
P. a f r i c a n a 5.650 ± 0.36
5a
12.623 ± 0.205
a
13.359 ± 0.025
a
15.848 ± 0.022
a
F. mucoso 1.541 ± 0.234
b
5.600 ± 0.300
b
10.863 ± 0.044
b
15.467 ± 0.404
a
Control 0.000 ± 0.000
c
0.000 ± 0.000
c
0.000 ± 0.000
c
0.000 ± 0.000
b
Table 1: Effect of P . africana and F. mucoso concentrations on adult mortality of C. maculatus
Values with the same letter (s) in the same column are not significantly different from each other at p < 0.05, HAT = Hour after treatment 

Acta agriculturae Slovenica, 117/3 – 2021 5
Effects of ... ethanolic leaves extract in the control of Callosobruchus maculatus (Fabricius, 1775) in stored cowpea
Life stages
Treatment Conc. (%) Oviposition Larvae Pupae
P . africana 10 4.333 ± 2.733
abc
2.000 ± 0.632
bc
2.667 ± 1.366
ab
30 2.500 ± 0.547
bcd
2.000 ± 1.265
bc
1.833 ± 1.169
ab
50 1.333 ± 0.516
d
0.833 ± 0.753
c
1.000 ± 0.894
b
F. mucoso 10 5.000 ± 1.673
ab
4.000 ± 1.265
a
3.500 ± 1.049
a
30 3.167 ± 0.983
abcd
2.500 ± 1.517
abc
2.500 ± 1.643
ab
50 1.833 ± 0.753
cd
1.667 ± 0.516
bc
2.167 ± 0.753
ab
Control 0 5.333 ± 1.751
a
4.333 ± 1.366
a
3.667 ± 1.211
a
Total effect of the botanical treatments
P . africana 2.722 ± 1.994
b
1.611 ± 1.036
c
1.833 ± 1.294
b
F. mucoso 3.333 ± 1.749
b
2.722 ± 1.487
b
2.722 ± 1.274
ab
Control 5.500 ± 1.567
a
3.833 ± 1.403
a
3.583 ± 1.443
a
Table 2: Effect of botanical types on the early life stages of C. maculatus
Values with the same letter (s) in the same column are not significantly different from each other at p < 0.05 
Adult emergence (DAT)
Treatment Conc. (%) 28 29 30 31 32
P . africana 10 2.500 ± 2.168
abc
2.833 ± 2.317
bc
3.333 ± 2.582
ab
3.833 ± 0.983
ab
3.500 ± 2.258
abc
 
30 1.667 ± 1.633
bc
2.333 ± 2.338
c
4.333 ± 1.751
ab
2.333 ± 1.033
b
1.500 ± 1.378
c
50 0.333 ± 0.817
c
0.333 ± 0.516
c
1.667 ± 1.211
b
1.667 ± 0.817
b
1.333 ± 0.516
c
F. mucoso 10 4.167 ± 1.169
ab
5.833 ± 2.483
ab
4.000 ± 0.632
ab
4.500 ± 2.509
ab
2.833 ± 1.169
abc
30 2.500 ± 2.509
abc
3.333 ± 2.422
bc
3.500 ± 1.517
ab
3.167 ± 1.941
ab
2.167 ± 1.472
bc
50 1.667 ± 2.066
bc
2.333 ± 1.211
c
4.667 ± 1.211
ab
3.500 ± 1.049
ab
2.667 ± 1.506
abc
Control 0 5.167 ± 1.722
a
6.667 ± 1.366
a
6.333 ± 2.582
a
5.833 ± 2.041
a
4.833 ± 1.169
a
Total effect of the botanical treatments 
P . africana 1.500 ± 1.791
b
1.833 ± 2.121
c
3.111 ± 2.139
b 
2.611 ± 1.289
b
2.111 ± 1.779
b
F. mucoso 2.778 ± 2.157
b
3.833 ± 2.503
b
4.056 ± 1.211
b
3.722 ± 1.904
ab
2.556 ± 1.338
b
Control 5.167 ± 1.801
a
6.333 ± 1.497
a
5.750 ± 2.179
a
4.750 ± 2.379
a
4.583 ± 1.311
a
Table 3: Effect of botanical treatment on emergence of C. maculatus adults
Values with the same letter (s) in the same column are not significantly different from each other at p < 0.05, DAT = Days after treatment

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T. D. OJUYEMI et al.
3.3 EFFECT OF THE BOTANICAL TREATMENT 
ON THE EMERGENCE OF ADULT C. macula-
tus F
1
 PROGENY
Results in Table 3 indicated both P. africana and 
F. mucoso leaves extract treatment at 50 % to have sig-
nificantly (p < 0.05) reduced the population of newly 
emerging C. maculatus adults at 28 and 29 days after 
treatment (DAT) when compared to the control. Sub-
sequent observations of the treatment effects on 30, 31 
and 32 DAT revealed seeds treated with P. africana at 
50 % concentration had the lowest number of adults 
that emerged than the rest of the treatments and the 
control as shown in Table 3. 
The overall treatment effects of the two botanicals 
on the emergence of F1 progeny of C. maculatus adults 
is presented in Table 3. At 28, 30 and 32 DAT, there was 
no significant difference between P . africana and F. mu-
coso leaves extract treatment which had the least popu-
lation of the insect pest compared to the control. At 29 
and 31 DAT, it was observed that overall treatment ef-
fect of P. africana had the least F1 progeny emergence 
than the F. mucoso treated seeds and the control (Table 
3). 
3.4 EFFECT OF THE BOTANICAL TREAT-
MENT ON COWPEA SEED VIABILITY
The results for floatation and germination test to 
check for cowpea seed viability after treatment with P. 
africana and F. mucoso leaves extract is presented in Ta-
ble 4. Overall, there was no significant (p > 0.05) differ-
ences detected between the various treatment groups 
and their concentrations in both the floatation and ger-
mination test carried out. 
On the other hand, the total effects of the treat-
ments indicated a significant difference with the con-
trol (7.167 ± 1.115) having the least seed viability in 
the floatation test in comparison to both the P . africana 
(8.833 ± 1.505) and F. mucoso (8.778 ± 1.263) treated 
seeds which had no difference (Table 4). The germina-
tion test indicated no significant (P>0.05) difference in 
seed viability considering the total effect of the botani-
cal treatments as inferred in Table 4.
Seed viability (%)
Treatment Conc. (%) Floatation Germination 
P . africana 10 8.500 ± 1.378
ab
6.333 ± 1.751
a
30 8.333 ± 2.066
ab
6.000 ± 1.789
a
50 9.667 ± 0.516
a
4.000 ± 1.414
a
F. mucoso 10 8.000 ± 1.673
ab
4.667 ± 2.160
a
30 9.167 ± 0.753
ab
5.667 ± 2.422
a
50 9.16 7± 0.983
ab
4.500 ± 1.378
a
Control 0 7.500 ± 1.049
ab
5.000 ± 2.168
a
Total effect of the botanical treatments
P . africana 8.833 ± 1.505
a
5.444 ± 1.886
a
F. mucoso 8.778 ± 1.263
a
4.944 ± 1.984
a
Control 7.167 ± 1.115
b
6.250 ± 2.179
a
Table 4: Effects of botanical treatment on seed viability
Phytochemicals Prosopis africana Ficus mucoso
Saponins + +
Tannins ++ ++
Flavonoids ++ -
Terpenoids +++ -
Alkaloids ++ +
Steroids + ++
Tabl e 5: Qualitative analysis of phytochemical composition of 
ethanolic leave extracts of Prosopis africana and Ficus mucoso
Values with the same letter (s) in the same col
Key: - = not present, + = present in very small concentration, ++ = 
present in moderately high concentration, +++ = present in very high 
concentration

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Effects of ... ethanolic leaves extract in the control of Callosobruchus maculatus (Fabricius, 1775) in stored cowpea
3.5 QUALITATIVE ANALYSIS OF PHYTO-
CHEMICAL COMPOSITION OF ETHANOLIC 
LEAVES EXTRACT OF BOTANICALS
Table 5 shows the qualitative analysis of phyto-
chemical composition of ethanolic leaves extract of the 
two botanicals. The result of the phytochemical screen-
ing indicated that saponins were present in very small 
concentrations in Prosopis africana and Ficus mucoso. 
Tannin was found to be present in moderately high 
concentrations in Prosopis africana and Ficus mucoso. 
Flavonoids were also found to be present in moderately 
high concentration in P. africana and not present in F. 
mucoso. Terpenoid was found to be present in very high 
concentration in P. africana and not present in F. mu-
coso. Furthermore, alkaloids were present in moderately 
high concentration in P. africana while in very small 
concentration in F. mucos o. Lastly, steroid was indicated 
in very small concentration in P . africana and present in 
moderately high concentration in F. mucoso as shown 
in Table 5.
4 DISCUSSION 
Several plant products have been studied to pos-
sess insecticidal properties against a wide range of 
insects, particularly agricultural pests (Abdullahi & 
Muhammad, 2004; Bishnu & Weisman, 2005; Swella & 
Mushobozy, 2007; Ajayi, 2007; Raja & William, 2008; 
Alan et al., 2009; Aly & Sahar, 2010). Extracts from such 
a plant have a natural tendency to break down rapidly 
and are environmentally safer as they produce no resi-
due effect (Islam, 2006). Herein in this work, we pre-
sented the first evidence-based trials on the bioactive 
potential of two different plant ethanolic leave extracts 
namely P. africana and F. mucoso in the control of C. 
maculatus infesting stored cowpea. The results obtained 
revealed that the extract of the two botanicals caused 
a significant rate of mortality on the insect pest. How-
ever, the cowpea seeds treated with P. africana leaves 
extract recorded the highest mean mortality of adult 
C. maculatus compared to F. mucoso, especially at the 
highest treatment concentration. The insecticidal effect 
of the plants ethanolic extracts on C. maculatus in the 
treated cowpea seeds might be a result of direct contact. 
Most insects breathe by means of trachea which usually 
open at the surface of the body through spiracles, the 
extract mixed with the seeds might have blocked these 
spiracles thereby leading to suffocation and death of the 
insects (Adedire & Akinkurolele, 2005; Rahman & Ta-
lukder, 2006; Akinkurolele et al., 2006). 
On the oviposition and emergence of a new gen-
eration of C. maculatus (larvae, pupae stage, and adult 
emergence) both P . africana and F . mucoso leave extracts 
were significantly effective in suppressing the popula-
tion of the insect especially when the dosage of the ex-
tracts was increased (although, seed lots treated with P 
africana were observed to have had the least population 
of the insect pest). This means that the plants leave ex-
tracts had insecticidal properties that inhibited egg-lay-
ing, larvae, pupation, and the emergence of new adults 
of the insect, the repellant effects by the plant materials 
inactivated the insect pest (Lale & Ofuya, 2001; Adedire 
et al., 2011; Ileke & Olotuah, 2012). Similar work using 
other plant materials was also reported by Lale & Ofuya 
(2001) who stated that botanicals with toxic constitu-
ents are effective in the suppression of the various life 
stages of insect pests, though, he did not work on P. 
africana and F. mucoso, this work shows that the two 
botanicals could be applied in restricting the various 
early life stages of C. maculatus.
The phytochemical analysis of the two botanicals 
revealed that they contained bioactive compounds such 
as alkaloids, steroids, saponins, tannins, flavonoids, and 
terpenoids with P. africana containing the vast major-
ity of the compounds in considerable amounts when 
compared to F. mucoso. The secondary plant metabo-
lites may be responsible for the insecticidal properties 
of the leave extracts (Kabaru & Gichia, 2009). Iwuala et 
al. (1981) stated that aromatic compounds such as ter-
penoids, flavonoids, and saponins have ovicidal, toxic, 
and deterrent effects on coleopterous insect pests in-
festing stored products. The presence of terpenoids in 
P. africana indicated that the plant extract could act as 
an antifeedant, growth disruptor and possessed con-
siderable toxicity toward insects’ pests of stored seeds 
(Khalid et al., 1989). Okwu (2001) also stated that ste-
roidal compounds which were more in F. mucoso play 
importance in pharmacy due to their relationship with 
such compounds as sex hormones and as such may be 
also responsible for disrupting the life cycle of the in-
sect pest. The phytochemicals richly identified in P. af-
ricana leaves extract may be attributed to the reason it 
has the highest mean mortality rate and lowest oviposi-
tion and emergence of the insect pest when compared 
to F. mucoso.
Seed viability test indicated no negative effects of 
the two botanical treatments on cowpea even at in-
creasing application rate of the treatment which did 
not differ from seeds that were not treated (the control) 
hence safe for usage on stored seeds before planting. 
It is conceivable to infer here that both P. africana and 
F. mucoso plant extracts offered a cheaper and sustain-
able alternative to synthetic insecticides (Mukanga et 

Acta agriculturae Slovenica, 117/3 – 2021 8
T. D. OJUYEMI et al.
al., 2010) in the control of C. maculatus infesting stored 
cowpea seeds.  
5 CONCLUSION
Many studies have addressed the insecticidal effi-
cacy of some plant species. Prosopis africana and Ficus 
mucoso ethanolic leaves extract were evaluated for in-
secticidal activity in this study. This research indicated 
that the plant material may be suitable for developing 
plant-based insecticides which are biodegradable and 
ecologically friendly. This could be further adopted by 
smallholder farmers in the usage against major stor-
age pests of cowpea. P . africana leaves extract had more 
insecticidal potential compared to F. mucoso, the latter 
could still be utilized especially in environments where 
they are growing in abundance if the former is lacking 
and as such could be integrated with other pest man-
agement approach in suppressing insect pests.
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