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Article

Pesticidal Potential and Selectivity of Soybean Extract on Pests and Non-Target Insects of Cocoa

by
Silas Wintuma Avicor
1,2,*,
Yahaya Bukari
2,3,
Michael Kojo Ainooson
4,
Godfred Kweku Awudzi
1 and
Wisdom Edem Anyomi
5
1
Entomology Division, Cocoa Research Institute of Ghana, New Tafo-Akim P.O. Box 8, Ghana
2
Bunso Cocoa College, Ghana Cocoa Board, Bunso P.O. Box 2, Ghana
3
Plant Pathology Division, Cocoa Research Institute of Ghana, New Tafo-Akim P.O. Box 8, Ghana
4
Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, Legon, Accra P.O. Box LG56, Ghana
5
Plant Breeding Division, Cocoa Research Institute of Ghana, New Tafo-Akim P.O. Box 8, Ghana
*
Author to whom correspondence should be addressed.
Crops 2025, 5(1), 7; https://doi.org/10.3390/crops5010007
Submission received: 20 December 2024 / Revised: 8 February 2025 / Accepted: 14 February 2025 / Published: 19 February 2025
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Abstract

:
With the search for alternative pest management strategies due to the concerns associated with synthetic pesticides, botanicals have been of increasing interest. However, the potential of plants such as soybean (Glycine max) as biopesticides is less known. Hence, this study assessed the activity of soybean extract (SBE) on insects and Phytophthora pod rot pathogens of cocoa using the filter paper contact toxicity and amended-agar plate techniques, respectively. Concentrations of 0.001–100% w/v SBE induced a mortality of 17.02–100% on the cocoa mirid Sahlbergella singularis and 2.5–90% and 5.26–100% on the ants Crematogaster africana and Pheidole megacephala, respectively. Also, 0.001–20% w/v SBE inhibited mycelial growth by 0–72% (Phytophthora palmivora isolates) and 1.17–81.03% (Phytophthora megakarya isolates). The minimum inhibitory concentration for P. palmivora and P. megakarya isolates was 1% and 0.001% w/v SBE, respectively. The median lethal concentration was 3.50% (S. singularis) and 193.73% w/v (C. africana), while the median inhibitory concentrations were 4.70 and 7.87% (P. palmivora isolates) and 1.13 and 1.48% (P. megakarya isolates). The activity of SBE on the pests was differential but non-toxic to the ant C. africana. The findings indicate the potential of SBE as a biopesticide against S. singularis and Phytophthora pod rot pathogens of cocoa.

1. Introduction

As a key agricultural produce in the colonial and postcolonial era, cocoa (Theobroma cacao) has shaped the political, social and economic landscape of several West African countries. It contributes significantly to livelihood, foreign exchange and gross domestic product in these countries. Although the West African sub-region accounts for about 70% of the global cocoa production, its production is impacted by several factors such as pests (insect pests and diseases) that result in yield deficits [1].
Mirids are ubiquitous in the cocoa-growing regions of Ghana [2,3], the second largest producer of the crop globally [4]. They feed on the pods, chupons and other soft tissues of the shoots [5], resulting in cherelle wilt, dieback of the stem, mirid blast and ‘stag-headed’ trees. The activity of mirids can cause severe yield losses of about 25–40% [6,7]. Other pests such as the Oomycota pathogens Phytophthora megakarya and Phytophthora palmivora are also important yield determinants in cocoa [1,8,9]. They cause Phytophthora pod rot of cocoa, resulting in severe yield losses of about 60 to 100% [10].
To narrow the yield gap, these pests are mostly targeted with synthetic pesticides [5,8,11,12]. This practice, however, has several concerns, including pesticide resistance and environmental and non-target toxicity. Hence, attempts to sustainably manage pests using alternatives that are safer to non-targets and the environment while being effective against pests have been made. Plants are among the environmentally safer alternatives for pest management [13]. Crude extracts of plants can be used by resource-limited farmers and the extracts can also serve as sources of lead compounds for pesticide development. As a result, extracts from many plant species have been experimented for potential use as pesticides [13,14,15].
Soybean (Glycine max) contains several phytochemicals, including alkaloids, polyphenols and saponins [16,17,18]. Some of these compounds are active against insects and microbes [17,19]. However, compared to other plant species, the pesticidal potential of soybean for agricultural use is less studied, with most of the reports focused on its antimicrobial activity against pathogens of medical importance [17,20]. Recently, Bukari et al. [21] reported on the effect of soybean extract on the causative agents of two cocoa diseases (pink and white thread blight) in Ghana and also on termite under laboratory conditions. However, for use in cocoa pest management, its activity on the major pests of cocoa needs to be known. This study therefore reports on the effect of soybean extract on the key insect pest and disease pathogens of the crop in Ghana. Although unintended, non-target organisms are exposed to chemical agents aimed against pests in the cocoa agro-ecosystem [3,22]. Non-target insects such as ants are commonly found in the cocoa ecosystem and play diverse ecological roles, including preying on pests [23,24,25,26]. Hence, knowledge on the impact of pest-targeted chemical agents on them is important for effective and sustainable pest management. As such, the effect of the extract on non-target species such as ants was also assessed to observe its relative safety towards them.

2. Materials and Methods

2.1. Biological Samples

Aqueous extract of soybean seeds sourced from Tamale, the capital city of the northern region of Ghana, was used. The extract was obtained as previously described in Bukari et al. [21] with some modifications as follows. Tap water was used to wash the seeds of soybean. The seeds were then washed with distilled water and dried under shade for 3 weeks. Afterwards, the seeds were ground into powder and 100 g of the powder was incubated with 100 mL of distilled water at room temperature for 24 h. This was mechanically pressed to obtain the aqueous form and then filtered with a muslin mesh to obtain the stock solution (100% w/v). This was repeated several times with different starting materials (soybean seed powders) to obtain enough stock solution for the study. The stock solution was diluted with distilled water to obtain the other concentrations. The soybean extract (SBE) concentrations (w/v) used were 0.001, 0.01, 0.1, 1, 10, 20, 40, 50, 70 and 100% for the insects and 0.001, 0.01, 0.1, 1, 10 and 20% for the Phytophthora pathogens.
The test insects (pest and worker ants) were collected from experimental cocoa plots (minimal insecticide exposure of 4× insecticide application per year and insecticide-free for 6 months prior to insect collection) at Cocoa Research Institute of Ghana (CRIG), New Tafo-Akim, Ghana, and held for at least 12 h prior to insecticide bioassay to remove weak and dead insects. Unsexed adult insects were used for the tests. The target insect (pest) was the mirid, Sahlbergella singularis (Hemiptera: Miridae), and the non-target insects were ants, Crematogaster africana (Hymenoptera: Formicidae) and Pheidole megacephala (Hymenoptera: Formicidae).
The isolates of P. palmivora (Peronosporales: Peronosporaceae) and P. megakarya (Peronosporales: Peronosporaceae) were obtained from the collections of the Mycology Laboratory of the Plant Pathology Division of CRIG. These pathogens were earlier isolated from black pod-infected pods, molecularly differentiated and stored in the laboratory on Oat Meal Agar (Becton Dickinson Company, MI, USA) at 4 °C [27]. The colony pattern of P. palmivora isolates on agar plates was stellate–striate with little aerial mycelium, while that of P. megakarya isolates was cotton-wool-like with aerial mycelium [28].

2.2. Laboratory Bioassays

2.2.1. Experiment I

A Whatman No. 1 filter paper (Whatman International Limited, Maidstone, UK) was moistened with 1 mL of soybean extract (SBE) and placed inside an 11 cm Petri dish (Corning Incorporated, Corning, NY, USA). Ten adult insects were placed on the filter paper and held at 27.5 ± 2.5 °C, 81 ± 6% relative humidity and approximately 12 h photoperiod. This was replicated at least 4 times for each concentration of the extract and a control (distilled water). Insect mortality after 24 h was recorded after probing with a camel hair brush. An insect was considered dead when it was nonresponsive (not moving or showing signs of movement) to 3 probes.

2.2.2. Experiment II

The activity of the SBE on mycelial growth of the test isolates of the pathogens, P. palmivora and P. megakarya, were performed using Carrot Dextrose Agar (CDA) (Oxoid Limited, London, UK) medium amended with the extract to the final test concentration as described in Bukari et al. [21]. Mycelium discs from each isolate were used to centrally inoculate the extract-amended plates. Nonamended CDA plates served as control. The plates were replicated 3 times and incubated at 28 ± 2 °C for 7 days. Inhibition of the mycelial growth of the pathogens was calculated as:
P I M R G = A − B A × 100
where PIMRG = percentage inhibition of mycelial radial growth; A = mean mycelial radial growth in control plates; and B = mean mycelial radial growth in test plates.

2.3. Data Analysis

Mortality data of the insects were corrected with the formula of Abbott [29] when the mortality in the control was 5–10%. The corrected mortality data were arcsine transformed and subjected to two-way analysis of variance (ANOVA). The data were also analyzed using probit to obtain the median lethal concentration (LC50).
The data on mycelial growth inhibition were arcsine transformed and subjected to two-way ANOVA. To obtain the median inhibitory concentration (IC50), the mycelial growth inhibition data were analyzed using probit.
Two-way ANOVA for both insect mortality and pathogen mycelial growth inhibition data was performed using IBM SPSS version 20 and the mean separation was performed using Tukey’s test at 5% significance level. Probit analysis was conducted using Insecticide Resistance Monitoring Application-QCal [30]. The LC50 and IC50 values with nonoverlapping 95% confidence interval (CI) were considered to be significantly different at 5% significance level.

3. Results

Figure 1 and Figure 2 present the uncorrected and corrected mortality, respectively, of the insect species exposed to the SBE extract. The lowest SBE concentration used in this study (0.001%) induced ≤10% mortality in the ant species (C. africana and P. megacephala) (Figure 1). This concentration, however, caused >20% mortality in S. singularis. For each SBE concentration, mortality in the target insect, S. singularis, was higher than that in the non-target C. africana. A similar trend was observed between S. singularis and the non-target P. megacephala except the two highest concentrations (70% and 100% w/v SBE), where mortality at 100% w/v was the same for both species and mortality at 70% w/v was higher in P. megacephala. Ant mortality stagnated from an SBE concentration of 0.1 to 20% w/v (C. africana) and 0.01 to 20% w/v (P. megacephala), while mirid mortality increased with increasing SBE concentration (Figure 1 and Figure 2). Mortality among the insect species was significantly different (p < 0.001). There was also a significant difference (p < 0.001) in the mortality induced by the various SBE concentrations. The insect species–extract concentration interaction effect was also significant (p < 0.001) (Figure 1).
The insects responded differently to the soybean extract. The extract was more toxic to the pest (S. singularis), with an LC50 of 3.5008%, compared to the ant, C. africana, which had an LC50 of 193.7304% (Table 1). The LC50 of S. singularis was significantly lower than that of C. africana, with the LC50 of the non-target insect, C. africana, being >55-fold higher than the target insect (S. singularis), indicating its safety towards the non-target. The mortality response of the insects was significantly different among the test species (Table 1).
Mycelial growth inhibition was higher in the P. megakarya isolates compared to the P. palmivora isolates (Figure 3). The SBE concentrations of 0.001 to 0.1% had no inhibitory effect on P. palmivora isolates. However, this concentration range had up to 5.88% and 16.22% inhibition of P. megakarya isolate 1 and P. megakarya isolate 2 mycelia growth, respectively. The minimum inhibitory concentration (MIC) of the P. megakarya isolates was 0.001% w/v, while that of the P. palmivora isolates was 1% w/v (Figure 3). There was a significant difference (p < 0.001) in inhibition among the pathogens and also among the extract concentrations used. A significant (p < 0.001) pathogen–extract concentration interaction effect was also observed (Figure 3).
Even though the IC50s of the Phytophthora isolates differed, these were not significant for each species. However, the IC50s of the two species were significantly different, with P. palmivora isolates having higher IC50 values compared to P. megakarya (Table 2).

4. Discussion

This study assessed the activity of SBE on three important insects (one key pest and two non-target ant species) of cocoa and two major disease-causing pathogens of cocoa pods. The concentration–mortality effect of SBE on the insect pest and disease pathogens was dose-dependent, with an increase in concentration eliciting an increase in response, thus mirid mortality or mycelial inhibition. A similar linear relationship between concentration and response has been reported in other insects and pathogens [21,31,32,33]. However, with the ants, until the 40% w/v SBE, mortality response to the lower concentrations was virtually static. For each SBE concentration, mirid mortality was higher than ant (C. africana) mortality, exemplifying the differential effect of the extract on these insect species. Similarly, SBE concentrations below 70% w/v induced higher mortality on S. singularis compared to the ant P. megacephala.
Toxicity of plant extracts towards S. singularis has been demonstrated in several studies [34,35,36,37]. Neem (Azadirachta indica) oil and ethanolic neem leaf extract induced a mortality of 52.5–97.5% and 32.5–92.5%, respectively, on S. singularis [35]. These mortality ranges compare favorably with the mortality induced by the SBE on S. singularis in the present study. Ayenor et al. [35] also reported a 100% mortality of mirids in cage experiments and at least 79% mortality in field experiments using aqueous neem seed extract (200 g/L). Although A. indica is a widely used biopesticide, Mboussi et al. [36] observed that aqueous extract of Thevetia peruviana seeds was more effective in managing S. singularis compared to A. indica seeds. Anikwe [37] also reported a mortality of 100, 80 and 80% on S. singularis using extracts (200 g/L) from Mangifera indica leaf, Acalypha wilkesiana leaf and A. indica stem bark via the direct contact toxicity method after 24 h. These reports [36,37] indicate the potential of other botanicals as biopesticides, although the plant parts used in Anikwe [37] differed among the neem and the other plant species. The higher mortality induced by these botanicals could be due to the composition and concentration of their secondary metabolites. It could also be due to the method of application or treatment of the insects. However, extracts from leaves of Anacardium occidentale induced 10% mortality [37], which is lower than the mirid mortality in our study at the same concentration, indicating the efficacy of the soybean extract. Using the residual contact toxicity, 50–200 g/L of M. indica leaf extracts induced 100% mortality on S. singularis [37], which is higher than the mortality of SBE on S. singularis at similar concentrations in our study.
Similar to our study, extracts from plants like Citrus hystrix, Mentha piperita and Ocimum basilicum induced high (93–95%) mortality on P. megacephala at a high concentration (1 × 106 ppm) [33]. This aligns with the mortality of the two ant species exposed to the highest concentration of the SBE, although C. africana mortality was lower. Ali and Ali [38] also showed that crude methanolic extract of garlic bulb induced a mortality of more than 95% in three Pheidole species after 24 h with a concentration of 25% w/v of nine plant extracts, inducing a mortality of less than 20% in the three Pheidole species.
Compared to other plants, studies on the efficacy of soybean extracts on insects are very few. In a study by Amer and Mehlorn [39] on three mosquito species (Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti), extract from soybean was not effective against these species. Another study by Amer and Mehlorn [40] further indicated that, while extracts from plants including camphor (Cinnamomum camphora), thyme (Thymus serpyllum) and lemon (Citrus limon) induced 100% mortality on third instar larvae of Aedes aegypti after 24 h post-treatment, the extract from soybean induced no mortality. This indicates the very low activity of extracts from soybean compared to other plants. However, the mortality induced by the SBE in this present study shows that it has activity against some insect species, though low compared to studies with other plant extracts. The activity of plant extracts may vary based on the test organism. For instance, while 100 and 50% neem oil induced a 50 and 8.3% mortality of the tick Amblyomma cohaereus, the same concentrations induced 100 and 75% mortality, respectively, of Amblyomma variegatum [41].
At 20% SBE, the highest inhibited mycelial growth of the P. palmivora isolates in this study was lower than that of P. megakarya and two pathogens, Marasmiellus scandens (86.8%) and Erythricium salmonicolor (80.4%), exposed to the extract in Bukari et al. [21]. These indicate a lower extract activity on P. palmivora compared to P. megakarya, M. scandens and E. salmonicolor. The inhibition activity observed in this study for P. megakarya was higher compared to that observed in Igboabuchi and Llodibia [20]. However, the inhibition effect on P. palmivora is similar to that of Igboabuchi and Llodibia [20]. The differing activities are reflected in the MICs, where those of the P. palmivora isolates were higher than the P. megakarya isolates. Comparing the findings to Bukari et al. [21] where E. salmonicolor isolates had MIC of 0.01% and M. scandens isolates had MIC of 0.001–0.1%, the MIC of P. palmivora is higher than the isolates of the three pathogens. However, the MIC of P. megakarya isolates is similar to an isolate of M. scandens and lower than other M. scandens and E. salmonicolor isolates.
The MICs of the P. megakarya and P. palmivora isolates are lower and higher, respectively, than the MIC (0.01%) of essential oil of soybean seeds on Bacillus subtilis and Escherichia coli [42]. Lower MICs (0.0025–0.0075%) have also been recorded using glyceollins from soybean seeds on the pathogens Fusarium oxysporum, Phytophthora capsici, Sclerotinia sclerotiorum and Botrytis cinera [43], although these were higher than the MIC observed on P. megakarya in this present study.
The LC50 values of the insects indicate a higher toxicity to S. singularis compared to C. africana. The extract was 55-fold more toxic to S. singularis, indicating its safety to the ant C. africana. The SBE mortality of the insects in this study could be due to its secondary metabolites, although these metabolites were not identified in the present study. Soybean extracts contain secondary metabolites, including alkaloids, polyphenols (such as isoflavones and phenolic acids), saponins, lycopene and ascorbic acid [17,18,20,44]. According to Kikuta [19], soybean isoflavones such as genistin and genistein induced toxic effects on the cells of Tribolium castaneum, with genistein producing a greater effect, hence the suggestion that it could be used as a T. castaneum oral biopesticide. Although some of the secondary metabolites may not induce mortality, they could act as synergists, as observed in the study by Hay et al. [45], where flavonoids from soybean did not induce mortality in Trichoplusia ni but, rather, synergistically enhanced the insecticidal activity of a baculovirus against T. ni.
The IC50 of the P. megakarya isolates indicate a similar inhibition response to the M. scandens isolates in Bukari et al. [21], although the IC50s of the P. megakarya isolates were higher than the IC50s of the E. salmonicolor and M. scandens. Hence, the SBE was less toxic to the P. palmivora isolates. Inhibition activity by the SBE could be due to its secondary metabolites like alkaloids, flavonoids, phenols and saponins [17,18,46,47]. Isoflavones from soybean also inhibit the synthesis of nucleic acid in S. aureus [48], while a soybean antifungal protein inhibits hyphal development and blocks nutrient uptake systems in Candida albicans [49].

5. Conclusions

Assaying soybean seed extract on an insect pest (Sahlbergella singularis), Phytophthora pod rot pathogens (Phytophthora megakarya and Phytophthora palmivora) and non-target ants (Crematogaster africana and Pheidole megacephala) of cocoa demonstrated that the extract was active on both the insect pest and Phytophthora spp. The extract was more toxic to the insect pest S. sahlbergella compared to the ants and relatively non-toxic to C. africana. Extract activity towards P. megakarya was higher compared to P. palmivora. The LC50 and IC50 on the pests, S. sahlbergella (LC50 = 3.50% w/v), P. megakarya (IC50s = 1.13 and 1.48% w/v) and P. palmivora (IC50s = 4.70 and 7.87% w/v), in comparison to the non-target C. africana (LC50 = 193.73% w/v) shows that the extract displays selectivity and safeness to the non-target. The findings indicate that incorporating the extract into the cropping system for pest management would not be impeded by the threat of toxicity to the two ant species. Further studies on the activity of the constituent compounds will help to identify the compounds responsible for the activity and towards the integration of the extract for use on cocoa.

Author Contributions

Conceptualization, S.W.A.; Methodology, S.W.A., Y.B., M.K.A., G.K.A. and W.E.A.; Validation, S.W.A. and Y.B.; Formal analysis, S.W.A. and Y.B.; Investigation, S.W.A., Y.B. and M.K.A.; Resources, S.W.A., Y.B., M.K.A., G.K.A. and W.E.A.; Data curation, S.W.A. and Y.B.; Writing—original draft preparation, S.W.A.; Writing—review and editing, S.W.A., Y.B., M.K.A., G.K.A. and W.E.A.; Visualization, S.W.A.; Supervision, S.W.A.; Project administration, S.W.A.; Funding acquisition, S.W.A. and M.K.A. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by University of Ghana Research Fund (grant number: UGRF/11/MDG-019/2018-2019) with logistical support from Ghana Cocoa Board/Cocoa Research Institute of Ghana (project code: CRIG/CC/04/13).

Data Availability Statement

Data are contained within the article.

Acknowledgments

The authors are thankful to staff of the Entomology and Plant Pathology Divisions of Cocoa Research Institute of Ghana, particularly Phebe Tagbor, for assisting with the experiments. The funding support of the University of Ghana is also acknowledged.

Conflicts of Interest

The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

References

  1. Wessel, M.; Quist-Wessel, P.M.F. Cocoa production in West Africa, a review and analysis of recent developments. NJAS Wagening. J. Life Sci. 2015, 74–75, 1–7. [Google Scholar] [CrossRef]
  2. Adu-Acheampong, R.; Jiggins, J.; van Huis, A.; Cudjoe, A.R.; Johnson, V.; Sakyi-Dawson, O.; Ofori-Frimpong, K.; Osei-Fosu, P.; Tei-Quartey, E.; Jonfia-Essien, W.; et al. The cocoa mirid (Hemiptera: Miridae) problem: Evidence to support new recommendations on the timing of insecticide application on cocoa in Ghana. Int. J. Trop. Insect. Sci. 2014, 34, 58–71. [Google Scholar] [CrossRef]
  3. Avicor, S.W.; Awudzi, G.K.; Adu-Acheampong, R.; Boamah-Dankyi, P.; Adu-Acheampong, S. Contact toxicity and proximate effect of fipronil on insect pest and predatory ant community structure in cocoa agro-ecosystem. J. Agric. Food Res. 2023, 14, 100909. [Google Scholar] [CrossRef]
  4. Statista. Global Cocoa Bean Production from 2020/21 to 2023/24, by Country. Available online: https://www.statista.com/statistics/263855/cocoa-bean-production-worldwide-by-region/ (accessed on 7 February 2025).
  5. Awudzi, G.K.; Adu-Acheampong, R.; Ahadzi, S.K.; Avicor, S.W. Field Guide for Cocoa Insect Pests Identification, Damage Symptoms and Management; Cocoa Research Institute of Ghana Technical Bulletin No. 28; Cocoa Research Institute of Ghana: New Tafo-Akim, Ghana, 2019; 27p. [Google Scholar]
  6. Padi, B.; Owusu, G.K. Towards an integrated pest management for sustainable cocoa production in Ghana. In Paper from Workshop in Panama 1998; Smithsonian Institute: Washington, DC, USA, 2003; p. 16. Available online: http://nationalzoo.sci.edu/scbi./migratorybirds/research/cacao/padi.cfm (accessed on 21 March 2018).
  7. N’Guessan, K.F. Major pests and diseases, situations and damage assessment, protocols in Côte d’Ivoire. In Proceedings of the Regional Workshop on Integrated Management of Cocoa Pests and Pathogens in Africa, Accra, Ghana, 15–18 April 2013. [Google Scholar]
  8. Opoku, I.Y.; Appiah, A.A.; Akrofi, A.Y.; Owusu, G.K. Phytophthora megakarya: A potential threat to the cocoa industry in Ghana. Ghana J. Agric. Sci. 2000, 33, 237–248. [Google Scholar] [CrossRef]
  9. Akrofi, A.Y.; Amoako-Atta, I.; Assuah, M.; Asare, E.K. Black pod disease on cacao (Theobroma cacao, L.) in Ghana: Spread of Phytophthora megakarya and role of economic plants in the disease epidemiology. Crop Prot. 2015, 72, 66–75. [Google Scholar] [CrossRef]
  10. Dakwa, J.T. A serious outbreak of blackpod disease in a marginal area of Ghana. In Proceedings of the 10th International Cocoa Research Conference, Santo Domingo, Dominican Republic, 17–23 May 1987. [Google Scholar]
  11. Adu-Acheampong, R.; Sarfo, J.E.; Appiah, E.F.; Nkansah, A.; Awudzi, G.; Obeng, E.; Tagbor, P.; Sem, R. Strategy for insect pest control in cocoa. Am. J. Exp. Agric. 2015, 6, 416–423. [Google Scholar] [CrossRef]
  12. Opoku, I.Y.; Akrofi, A.Y.; Appiah, A.A. Assessment of sanitation and fungicide application directed at cocoa tree trunks for the control of Phytophthora black pod infections in pods growing in the canopy. Eur. J. Plant Pathol. 2007, 117, 167–175. [Google Scholar] [CrossRef]
  13. Pavela, R. Essential oils for the development of ecofriendly mosquito larvicides: A review. Ind. Crops Prod. 2015, 76, 174–187. [Google Scholar] [CrossRef]
  14. Avicor, S.W.; Wajidi, M.F.F.; Achoribo, E.S.; Ong, M.T.; Hamzah, S.N. Tiger nut (Cyperus esculentus) as a potential phytoinsecticide: Larvicidal activity of crude extracts on Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae). Trop. Biomed. 2021, 38, 186–191. [Google Scholar] [CrossRef] [PubMed]
  15. Gagman, H.A.; Ahmad, H.; Him, N.A.I.I.N.; Avicor, S.W. In vitro assessment of deworming potential of Guiera senegalensis in Nigerian ethnoveterinary industry using Caenorhabditis elegans. Bull. Natl. Res. Cent. 2022, 46, 3. [Google Scholar] [CrossRef]
  16. Alghamdi, S.S.; Khan, M.A.; El-Harty, E.H.; Ammar, M.H.; Farooq, M.; Migdadi, H.M. Comparative phytochemical profiling of different soybean (Glycine max (L.) Merr) genotypes using GC–MS. Saudi J. Biol. Sci. 2018, 25, 15–21. [Google Scholar] [CrossRef] [PubMed]
  17. Villalobos, M.D.C.; Serradilla, M.J.; Martin, S.; Ordiales, E.; Ruiz-Moyano, S.; Córdoba, M.D.G. Antioxidant and antimicrobial activity of natural phenolic extract from defatted soybean flour by-product for stone fruit postharvest application. J. Sci. Food Agric. 2016, 96, 2116–2124. [Google Scholar] [CrossRef] [PubMed]
  18. Lisanti, E.; Arwin, A. Phytochemical screening and proximate analysis of soybeans (Glycine max) variety Gamasugen 1 and Gamasugen 2 derived from gamma rays irradiation. J. Phys. Conf. Ser. 2019, 1402, 055023. [Google Scholar] [CrossRef]
  19. Kikuta, S. The cytotoxic effect of genistein, a soybean isoflavone, against cultured Tribolium cells. Insects 2020, 11, 241. [Google Scholar] [CrossRef] [PubMed]
  20. Igboabuchi, N.A.; Llodibia, C.V. A study on the antioxidant and antimicrobial activities of seed and leaf extracs of Glycine max (L) Merr. Asian J. Res. Bot. 2018, 1, 1–8. [Google Scholar]
  21. Bukari, Y.; Avicor, S.W.; Awudzi, G.; Ainooson, M.K.; Asare, E.K.; Amoako-Attah, I. In vitro activity of soybean extract on cocoa disease pathogens (Erythricium salmonicolor and Marasmiellus scandens) and termite pest (Microtermes subhyalinus). Cogent Food Agric. 2022, 8, 2147474. [Google Scholar] [CrossRef]
  22. Zakaria, N.; Norhisham, A.R.; Yasmin, I.; Yahya, M.S.; Sanusi, R.; Azhar, B. Insecticides may compromise the benefits of tree-crop diversification on arthropod biodiversity in cocoa agroforestry smallholdings. Agroecol. Sustain. Food Syst. 2024, 48, 1068–1093. [Google Scholar] [CrossRef]
  23. Entwistle, P.F. Pests of Cocoa; Longman Group Ltd.: London, UK, 1972; pp. 275–288. [Google Scholar]
  24. Bisseleua, D.H.B.; Begoude, D.; Tonnang, H.; Vidal, S. Ant-mediated ecosystem services and disservices on market yield in cocoa. Agric. Ecosyst. Environ. 2017, 247, 409–417. [Google Scholar] [CrossRef]
  25. Diamé, L.; Rey, J.-Y.; Vayssières, J.-F.; Grechi, I.; Chailleux, A.; Diarra, K. Ants: Major functional elements in fruit agro-ecosystems and biological control agents. Sustainability 2018, 10, 23. [Google Scholar] [CrossRef]
  26. Akesse-Ransford, G.; Owusu, E.O.; Kyerematen, R.; Adu-Acheampong, S. Arthropod diversity of cocoa farms under two management systems in the Eastern and Central regions of Ghana. Agrofor. Syst. 2021, 95, 791–803. [Google Scholar] [CrossRef]
  27. Ali, S.S.; Amoako-Attah, I.; Bailey, R.A.; Strem, M.D.; Schmidt, M.; Akrofi, A.Y.; Surujdeo-Maharaj, S.; Kolawole, O.O.; Begoude, B.A.D.; ten Hoopen, G.M.; et al. PCR-based identification of cacao black pod causal agents and identification of biological factors possibly contributing to Phytophthora megakarya’s field dominance in West Africa. Plant Pathol. 2016, 65, 1095–1108. [Google Scholar] [CrossRef]
  28. Opoku, I.Y. Field and Laboratory Characterization of Phytophthora palmivora and Phytophthora megakarya in Ghana; Cocoa Research Institute of Ghana Technical Bulletin No. 15; Cocoa Research Institute of Ghana: New Tafo-Akim, Ghana, 2004; 24p. [Google Scholar]
  29. Abbott, W.S. A method of computing the effectiveness of an insecticide. J. Econ. Entomol. 1925, 18, 265–267. [Google Scholar] [CrossRef]
  30. Lozano-Fuentes, S.; Saavedra-Rodriguez, K.; Black IV, W.C.; Eisen, L. QCal: A software application for the calculation of dose-response curves in insecticide resistance bioassays. J. Am. Mosq. Control Assoc. 2012, 28, 59–61. [Google Scholar] [CrossRef] [PubMed]
  31. Mohammadi, A.; Hashemi, M.; Hosseini, M.S. Comparison of antifungal activities of various essential oils on the Phytophthora drechsleri, the causal agent of fruit decay. Iran. J. Microbiol. 2015, 7, 31–37. [Google Scholar] [PubMed]
  32. Hosseini Chaleshtori, S.A.; Ataie Kachouie, M.A.; Hashemi Jazi, S.M. Antibacterial effects of the methanolic extract of Glycine max (soybean). Microbiol. Res. 2017, 8, 7319. [Google Scholar] [CrossRef]
  33. Lim, L.; Ab Majid, A.H. Plant derived pesticides (Citrus hystrix DC, Mentha × piperita L., Ocimum basilicum L.) in controlling household ants (Tapinoma indicum (F.), Pheidole megacephala (F.), Monomorium pharaonis (L.)) (Hymenoptera: Formicidae). Pertanika J. Trop. Agric. Sci. 2019, 42, 1321–1342. [Google Scholar]
  34. Mahob, R.J.; Taliedje, D.M.; Mahot, H.C.; Mama Ngah, I.; Eteme Enama, S.; Cilas, C.; Fotso Toguem, Y.G.; Hanna, R.; Bilong Bilong, C.F. Biocontrol of the brown cocoa mirids using neem oil and an ethanolic extract from neem under laboratory conditions. Afr. Entomol. 2021, 29, 507–521. [Google Scholar] [CrossRef]
  35. Ayenor, G.K.; Van Huis, A.; Obeng-Ofori, D.; Padi, B.; Röling, N.G. Facilitating the use of alternative capsid control methods towards sustainable production of organic cocoa in Ghana. Int. J. Trop. Insect Sci. 2007, 27, 85–94. [Google Scholar] [CrossRef]
  36. Mboussi, S.B.; Ambang, Z.; Kakam, S.; Bagny Beilhe, L.; Tejada Moral, M. Control of cocoa mirids using aqueous extracts of Thevetia peruviana and Azadirachta indica. Cogent Food Agric. 2018, 4, 1430470. [Google Scholar] [CrossRef]
  37. Anikwe, J.C. Laboratory bioassay of selected plant extracts for the control of brown cocoa mirid, Sahlbergella singularis Haglund (Hemiptera: Miridae). J. Entomol. Nematol. 2013, 5, 29–32. [Google Scholar] [CrossRef]
  38. Ali, A.S.; Ali, M.F. Toxicity of some extracts of common plants towards three species of Pheidole ants under laboratory conditions. Egypt. Acad. J. Biol. Sci. 2019, 13, 185–194. [Google Scholar] [CrossRef]
  39. Amer, A.; Mehlhorn, H. Repellency effect of forty-one essential oils against Aedes, Anopheles, and Culex mosquitoes. Parasitol. Res. 2006, 99, 478–490. [Google Scholar] [CrossRef]
  40. Amer, A.; Mehlhorn, H. Larvicidal effects of various essential oils against Aedes, Anopheles, and Culex larvae (Diptera, Culicidae). Parasitol. Res. 2006, 99, 466–472. [Google Scholar] [CrossRef]
  41. Siyoun, T.; Basu, A.K.; Tihalun, G.; Kumsa, B. Study on the acaricidal effects of Azadirachta indica and Phytolacca dodecandra on Amblyomma ticks in Ethiopia. Ethiop. Vet. J. 2014, 18, 1–14. [Google Scholar]
  42. Ghahari, S.; Alinezhad, H.; Nematzadeh, G.; Tajbakhsh, M.; Baharfar, R. Chemical composition, antioxidant and biological activities of the essential oil and extract of the seeds of Glycine max (soybean) from North Iran. Curr. Microbiol. 2017, 74, 522–531. [Google Scholar] [CrossRef]
  43. Kim, H.J.; Suh, H.J.; Lee, C.H.; Kim, J.H.; Kang, S.C.; Park, S.; Kim, J.S. Antifungal activity of glyceollins isolated from soybean elicited with Aspergillus sojae. J. Agric. Food Chem. 2010, 58, 9483–9487. [Google Scholar] [CrossRef] [PubMed]
  44. Balanescu, F.; Busuioc, A.C.; Botezatu, A.V.D.; Gosav, S.; Avramescu, S.M.; Furdui, B.; Dinica, R.M. Comparative study of natural antioxidants from Glycine max, Anethum graveolens and Pimpinella anisum seed and sprout extracts obtained by ultrasound-assisted extraction. Separations 2022, 9, 152. [Google Scholar] [CrossRef]
  45. Hay, W.T.; Behle, R.W.; Berhow, M.A.; Miller, A.C.; Sterling, G.W. Biopesticide synergy when combining plant flavonoids and entomopathogenic baculovirus. Sci. Rep. 2020, 10, 6806. [Google Scholar] [CrossRef] [PubMed]
  46. Cowan, M.M. Plant products as anti- microbial agents. Clin. Microbiol. Rev. 1999, 12, 564–582. [Google Scholar] [CrossRef] [PubMed]
  47. Dahanukar, S.A.; Kulkarni, R.A.; Rege, N.N. Pharmacology of medicinal plants and natural products. Indian J. Pharmacol. 2000, 32, S81–S118. [Google Scholar]
  48. Wang, Q.; Wang, H.; Xie, M. Antibacterial mechanism of soybean isoflavone on Staphylococcus aureus. Arch. Microbiol. 2010, 192, 893–898. [Google Scholar] [CrossRef] [PubMed]
  49. Morais, J.K.S.; Bader, O.; Weig, M.; Oliveira, J.T.A.; Arantes, M.R.; Gomes, V.M.; Da Cunha, M.; Oliveira, D.H.; Sousa, O.B.D.; Lourencao, L.A.; et al. Soybean Toxin (SBTX) impairs fungal growth by interfering with molecular transport, carbohydrate/amino acid metabolism and drug/stress responses. PLoS ONE 2013, 8, e70425. [Google Scholar] [CrossRef] [PubMed]
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Figure 1. Insect mortality after a 24 h exposure to concentrations (w/v) of soybean extract. Control 1: distilled water; Control 2: distilled water. The error bars denote standard error. Mean values (bars) with the same letter are not significantly different at p < 0.05.
Figure 1. Insect mortality after a 24 h exposure to concentrations (w/v) of soybean extract. Control 1: distilled water; Control 2: distilled water. The error bars denote standard error. Mean values (bars) with the same letter are not significantly different at p < 0.05.
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Figure 2. Corrected mortality of insect species after a 24 h exposure to concentrations (w/v) of soybean extract. Mortality was corrected with Abbott’s [29] formula when mortality in the control was 5–20%.
Figure 2. Corrected mortality of insect species after a 24 h exposure to concentrations (w/v) of soybean extract. Mortality was corrected with Abbott’s [29] formula when mortality in the control was 5–20%.
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Figure 3. Mycelial growth inhibition of Phytophthora species on soybean-extract-amended agar after 7 days of incubation. Phytophthora megakarya 1: Phytophthora megakarya isolate 1; Phytophthora megakarya 2: Phytophthora megakarya isolate 2; Phytophthora palmivora 1: Phytophthora palmivora isolate 1; Phytophthora palmivora 2: Phytophthora palmivora isolate 2. The error bars denote standard error. Mean values (bars) with the same letter are not significantly different at p < 0.05.
Figure 3. Mycelial growth inhibition of Phytophthora species on soybean-extract-amended agar after 7 days of incubation. Phytophthora megakarya 1: Phytophthora megakarya isolate 1; Phytophthora megakarya 2: Phytophthora megakarya isolate 2; Phytophthora palmivora 1: Phytophthora palmivora isolate 1; Phytophthora palmivora 2: Phytophthora palmivora isolate 2. The error bars denote standard error. Mean values (bars) with the same letter are not significantly different at p < 0.05.
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Table 1. Median lethal concentration of soybean extract on insects after a 24 h contact exposure.
Table 1. Median lethal concentration of soybean extract on insects after a 24 h contact exposure.
InsectLC50 (% w/v)95% CISlope ± SEIntercept ± SE
Sahlbergella singularis3.5008 a2.1297–5.75400.2807 ± 0.0219−0.3517 ± 0.0787
Crematogaster africana193.7304 b109.4207–342.98960.4471 ± 0.0502−2.3549 ± 0.1846
Pheidole megacephala----
LC50: median lethal concentration; 95% CI: 95% confidence interval; SE: standard error; -: LC50 could not be computed. LC50s with different superscripts are significantly different.
Table 2. Median inhibitory concentration of mycelial growth of Phytophthora pod rot pathogens after incubation for 7 days on soybean-extract-amended agar.
Table 2. Median inhibitory concentration of mycelial growth of Phytophthora pod rot pathogens after incubation for 7 days on soybean-extract-amended agar.
PathogenIC50 (% w/v)95% CISlope ± SEIntercept ± SE
Phytophthora megakarya 11.4843 a1.05253–2.093210.6867 ± 0.0539−0.2712 ± 0.1227
Phytophthora megakarya 21.1256 a0.76277–1.660970.5612 ± 0.0437−0.0664 ± 0.1114
Phytophthora palmivora 17.8737 b5.68198–10.910220.7605 ± 0.0758−1.5694 ± 0.1796
Phytophthora palmivora 24.7038 b3.38922–6.5279960.7323 ± 0.0660−1.1339 ± 0.1517
IC50: median inhibitory concentration; 95% CI: 95% confidence interval; SE: standard error. Phytophthora megakarya 1: Phytophthora megakarya isolate 1; Phytophthora megakarya 2: Phytophthora megakarya isolate 2; Phytophthora palmivora 1: Phytophthora palmivora isolate 1; Phytophthora palmivora 2: Phytophthora palmivora isolate 2. IC50s with different superscripts are significantly different.
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Avicor, S.W.; Bukari, Y.; Ainooson, M.K.; Awudzi, G.K.; Anyomi, W.E. Pesticidal Potential and Selectivity of Soybean Extract on Pests and Non-Target Insects of Cocoa. Crops 2025, 5, 7. https://doi.org/10.3390/crops5010007

AMA Style

Avicor SW, Bukari Y, Ainooson MK, Awudzi GK, Anyomi WE. Pesticidal Potential and Selectivity of Soybean Extract on Pests and Non-Target Insects of Cocoa. Crops. 2025; 5(1):7. https://doi.org/10.3390/crops5010007

Chicago/Turabian Style

Avicor, Silas Wintuma, Yahaya Bukari, Michael Kojo Ainooson, Godfred Kweku Awudzi, and Wisdom Edem Anyomi. 2025. "Pesticidal Potential and Selectivity of Soybean Extract on Pests and Non-Target Insects of Cocoa" Crops 5, no. 1: 7. https://doi.org/10.3390/crops5010007

APA Style

Avicor, S. W., Bukari, Y., Ainooson, M. K., Awudzi, G. K., & Anyomi, W. E. (2025). Pesticidal Potential and Selectivity of Soybean Extract on Pests and Non-Target Insects of Cocoa. Crops, 5(1), 7. https://doi.org/10.3390/crops5010007

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