Good Biological Control Research Articles

Biological Control of Avocado Branch Blight Caused by Lasiodiplodia theobromae Using Bacillus velezensis.

In recent years, avocado branch blight has gradually become one of the major diseases causing mortality of avocado trees, which seriously affects the economic development of avocado planting regions. In order to investigate the cause of the disease, the pathogens were isolated from the interroot of avocado trees with the onset of the disease and identified as Lasiodiplodia theobromae. At the same time, three Bacillus velezensis strains, YK194, YK201, and YK268, with better antagonistic effects and high stability against L. theobromae, were isolated from the rhizospheric soil of healthy avocado plants. The results of branch experiments and field trials showed that the avocado leaves as well as branches treated with the strains YK194, YK201, and YK268 did not develop disease, and the incidence of avocado trees was significantly reduced. In the branch experiments, the biological control effect of the strains YK194, YK201, and YK268 reached 62.07, 52.70, and 72.45%, respectively. In the field experiments, it reached 63.85, 63.43, and 73.86%, respectively, which indicated that all these three strains possessed good biological control effects on avocado branch blight. Further investigation on the mechanism of action of antagonistic strains revealed that B. velezensis YK268 could produce lipopeptides, namely, surfactin, fengycin, and iturin, which could significantly inhibit the spore germination of L. theobromae. Consequently, these three isolates have potential as biocontrol agents against L. theobromae.

To move or not to move: Dispersal of Orius insidiosus in strawberry plants

AbstractSpatial and temporal distribution of food resources influences predatory insects' foraging and dispersal behavior. Orius insidiosus (Say) (Hemiptera: Anthocoridae) is a good biological control agent of western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), in the strawberry crop and consumes two‐spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae), and pollen as well. Augmentative biological control programs may fail if, following release, predators disperse from the crop. We studied the dispersal of O. insidiosus as a function of pollen availability, density of their main prey WFT, and the presence of the alternative prey TSSM, within and between strawberry plants. We found that O. insidiosus remained on the flowers during the 24 h of the assay. The dispersal of predators to a neighboring flower with thrips was approximately six times greater from a flower without pollen than from a flower with pollen. When TSSM was the only prey available, O. insidiosus colonized the leaves, and its dispersal within the plant was greater. At the plot scale, the predator dispersal from the release plant to other plants also depended on the presence of flowering plants and prey. Our results highlight the importance of flowering plants and pollen availability in enhancing the persistence of O. insidiosus in strawberry plants. Releases of this predator in the strawberry crop should be after the beginning of flowering, even at low WFT densities.

Effective biological control of chickpea rabies (Ascochyta rabiei) through systemic phytochemical defenses activation by Trichoderma roots colonization: From strain characterization to seed coating

Chickpea (Cicer arietinum) is a legume of great economic and agricultural importance worldwide, whose crop is severely affected by rust or Ascochyta blight, caused by the fungus Ascochyta rabiei. The fungal genus Trichoderma includes several species widely characterized as effective biological control agents against crop pathogens. First, this work characterized several species of the genus Trichoderma as potential biological control agents of A. rabiei directly (in vitro confrontation) or indirectly in chickpea plants (activation of systemic resistance), selecting T. harzianum EN1 as the most efficient strain. Subsequently, different materials were tested as coatings to apply the T. harzianum conidia on chickpea seeds, determining that gum arabic at 1 % concentration was the one that most promoted the germination of conidia and seeds. The third phase of the study was based on the application of the coating and T. harzianum conidia on chickpea seeds and to study plant survival after infection with the pathogen A. rabiei, characterizing root colonization by Trichoderma and systemic hormonal and metabolic changes related to the induction of systemic defenses. The treatment of chickpea seeds with gum arabic and T. harzianum conidia was found to increase Trichoderma-root colonization and to improve plant survival. The induction of systemic ethylene- and melatonin-mediated resistance, which led to the accumulation of nicotinic acid in plant tissues, was considered the cause of such a protection. Therefore, T. harzianum applied as seed coating with gum arabic could be a good biological control strategy against A. rabiei on chickpea, due to the induction of systemic resistance.

Study on the mechanism of peanut resistance to Fusarium oxysporum infection induced by Bacillus thuringiensis TG5.

Peanut root rot, commonly referred to as rat tail or root rot, is caused by a range of Fusarium species. A strain of bacteria (named TG5) was isolated from crop rhizosphere soil in Mount Taishan, Shandong Province, China, through whole genome sequencing that TG5 was identified as Bacillus thuringiensis, which can specifically produce chloramphenicol, bacitracin, clarithromycin, lichen VK21A1 and bacitracin, with good biological control potential. Based on liquid chromatography tandem mass spectrometry metabonomics analysis and transcriptome conjoint analysis, the mechanism of TG5 and carbendazim inducing peanut plants to resist F. oxysporum stress was studied. In general, for peanut root rot caused by F. oxysporum, B. thuringiensis TG5 has greater advantages than carbendazim and is environmentally friendly. These findings provide new insights for peanut crop genetics and breeding, and for microbial pesticides to replace traditional highly toxic and highly polluting chemical pesticides. Based on the current background of agricultural green cycle and sustainable development, it has significant practical significance and broad application prospects.

Optimal control and cost effectiveness analysis of contamination associated with aflatoxins in maize kernels, livestock and humans

Aflatoxin contamination poses a significant challenge in food safety and security as it affects both health of consumers and supply chains. Due to health impacts associated with aflatoxin contamination, countries have set standards and restrictions for importing food crops and animal feed, resulting in greater economic losses to farmers, transporters, and crop processors. Three controls, namely good farming practices, biological control and public education and awareness campaigns, have been mostly used in countries where aflatoxin contamination has occurred. Since resources are scarce, there is a need to find the optimal and cost-effective strategy to reduce the burden on farmers. This study aimed to find optimal and cost-effective control strategy to mitigated aflatoxin contamination in maize kernels, livestock and humans. A deterministic model was developed and analyzed for studying the impact of implementing three time dependent controls on the dynamics and control of aflatoxin contamination in maize kernels, livestock and humans. We use optimal control theory to find the necessary conditions for existence of the optimal controls and to determine the optimal strategy for controlling the aflatoxin contamination. We also carry out cost-effectiveness analysis through Incremental Cost Effective Ratio (ICER) to obtain the most effective strategy. Simulation results for the optimal control problem suggest that strategy which involve implementation of all controls performs well than other strategies in controlling the aflatoxin contamination in maize kernels, livestock and humans. Therefore, to control aflatoxin contamination initiatives should focus on good farming practices, biological control and public education and awareness campaigns.

Ectoparasitoid Dinarmus basalis causes greater offspring loss to the winged morph of Callosobruchus maculatus

The pest cowpea weevil Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) exhibits polymorphism with flight and flightless forms that differ in morphology and life-history. Flight forms are generally dispersers with lower fecundity that increase in frequency when population density and intraspecific competition are both high. Callosobruchus maculatus larvae can cause important damage to stored grains and the solitary ectoparasitoid Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae) is considered to be a good candidate biological control agent. However, whether morphs differ in the likelihood of their offspring surviving attack is unknown. Understanding this has implications for the pest status of the cowpea weevil following biological control. We found that attack by D. basalis lowered the number of emerging offspring produced by both morphs. The ectoparasitoid was most effective at reducing survival of larvae produced by flight morph parents, suggesting that there may be a further cost of dispersal for C. maculatus. Parental morph type did not influence D. basalis behavior or development when foraging, so the biological mechanism resulting in this difference remains unclear. Nevertheless, our study shows that D. basalis affects the offspring of both weevil morphs, as required for an effective biocontrol agent. These results contribute to our understanding of how intraspecific variation, including polymorphism, influences species interactions among biological control agents and their target insect pests.

Developmental Biology of Trichospilus pupivorus Ferrière (Hymenoptera: Eulophidae), a Pupal Parasitoid of the Coconut Black-headed Caterpillar, Opisina arenosella Walker (Lepidoptera: Xyloryctidae)

Background: The coconut black-headed caterpillar, Opisina arenosella Walker (Lepidoptera: Xyloryctidae) has been a serious defoliator of coconut plants in many coconut producing countries including Vietnam. Trichospilus pupivorus Ferrière (Hymenoptera: Eulophidae) is pupal endo-parasitoid of O. arenosella with high percent parasitism and abundance in the coconut fields and appears to be a good biological control agent against the coconut black-headed caterpillar in Vietnam. The objective of this study was to investigate the developmental biology of T. pupivorus on O. arenosella. Methods: The experiment was carried out at the Faculty of Agronomy, Nong Lam University, Viet Nam during 2020 and 2021. The developmental biology of T. pupivorus on O. arenosella was studied in the laboratory at a constant temperature of 28°C and a photoperiod of 12L: 8D. Result: Total developmental time from egg to adult emergence was 14.0 days. The females laid a mean of 124.2 eggs during an average lifespan of 9.4 days. The number of progenies emergence from a single pupa of O. arenosella was 103.8. The offspring sex ratio was female-biased (8.0%). The results would contribute to the knowledge of the biology of this parasitoid to optimize a mass rearing system for a biological control program against O. arenosella.

Biology of Brachymeria kamijoi Habu (Hymenoptera: Chalcididae), a pupal parasitoid of the coconut black-headed caterpillar, Opisina arenosella Walker (Lepidoptera: Xyloryctidae)

The coconut black-headed caterpillar, Opisina arenosella Walker (Lepidoptera: Xyloryctidae) has been one of the most serious defoliators of coconut plants in Vietnam. Brachymeria kamijoi Habu (Hymenoptera: Chalcididae) is a pupal parasitoid of O. arenosella with high percent parasitism and abundance in the coconut fields and appears to be a good biological control agent against the coconut black-headed caterpillar in Vietnam. This study was carried out at Entomology Laboratory, Faculty of Agronomy, Nong Lam University, Vietnam during 2020 – 2021 to determine some biological characteristics of B. kamijoi on O. arenosella at a constant temperature of 28 oC and a photoperiod of 12L: 8D. Total developmental time from egg to adult emergence was 13.8 days. The females laid a mean of 98.1 eggs during an average lifespan of 30.7 days. Fecundity peaked at a large range of age 7 -29 days. The results would contribute to the knowledge of the biology of B. kamijoi to optimize a mass-rearing system for a biological control programme against O. arenosella.

A New Record to Rust Fungi of South Western Province Kandahar, Afghanistan

A rust fungus occurring on Centaurea iberica leaves from Arghandab district, southwestern province Kandahar Afghanistan is described and illustrated. A critical morphological and microscopical examination revealed it to be Puccinia calcitrapae. After conducting a literature survey, it was found that this fungus is the first record to be reported from southwestern province Kandahar. A detailed taxonomic description of this fungus along with its distribution is provided. Weeds cause serious problems in agriculture in Afghanistan especially in southwestern province Kandahar. These plants reduce yield and the quality of crops by competing for water, nutrients and sunlight. The improper or excessive usage of herbicides has led to development of resistance in some weed species while contaminating the environment; therefore, biological control has an increasing role as an alternative method for controlling special weed. Previous studies in other countries revealed that this rust fungus are good biological control agents for these weeds.

Secondary Metabolites of Purpureocilliumlilacinum.

Fungi can synthesize a wealth of secondary metabolites, which are widely used in the exploration of lead compounds of pharmaceutical or agricultural importance. Beauveria, Metarhizium, and Cordyceps are the most extensively studied fungi in which a large number of biologically active metabolites have been identified. However, relatively little attention has been paid to Purpureocillium lilacinum. P. lilacinum are soil-habituated fungi that are widely distributed in nature and are very important biocontrol fungi in agriculture, providing good biological control of plant parasitic nematodes and having a significant effect on Aphidoidea, Tetranychus cinnbarinus, and Aleyrodidae. At the same time, it produces secondary metabolites with various biological activities such as anticancer, antimicrobial, and insecticidal. This review attempts to provide a comprehensive overview of the secondary metabolites of P. lilacinum, with emphasis on the chemical diversity and biological activity of these secondary metabolites and the biosynthetic pathways, and gives new insight into the secondary metabolites of medical and entomogenous fungi, which is expected to provide a reference for the development of medicine and agrochemicals in the future.

Cover Caption

Cotesia vestalis has been used as a good biological control agent for management the pest of global cruciferous plants, Plutella xylostella. The successful parasitization strictly relies on C. vestalis olfactory perception, and odorant binding protein (OBP) play a key role in searching for hosts (see pages 1354‐1368). The cover photo shows C. vestalis is parasitizing the host with the help of three OBP genes expressed in C. vestalis antennae for locating P. xylostalla larva. Photo provided by Xi‐Qian Ye.

Molecular Characterization and Fungicidal Activity of some Isolated Endophytic Fungi from some Wild Plants in Egypt

Endophytic fungi have several beneficial properties like the production of various bioactive compounds and antimicrobial impacts against many plant pathogens. So, they are qualified to be good biological control agents. The present study aimed to detect endophytic fungal isolates from eight wild plants in Egypt, identify these isolated fungal strains, determine the colonization frequency %, the most prevalent fungal strains and study the antimicrobial activity of these dominant isolates. Fifteen endophytic fungal strain was isolated from the selected wild plant species and morphologically identified. The most four dominant fungal strains were selected and confirmed their identification based on the internal transcribed spacer (ITS) region sequence by using the polymerase chain reaction (PCR) with the primer pairs ITS1/ITS4. The results revealed that among the selected plant species, Calotropis procera had the highest endophytic fungi diversity (relative frequency 25%). The most dominant isolates were molecularly identified as Aspergillus niger, and Beauveria bassiana with dominance percentage 15.25% followed by A. terreus (13.5%) then Trichoderma harzianum (11.86%). The antagonistic activity of these four isolates against some plant pathogenic fungi using both dual culture technique and the ethyl extracts of these isolates at different concentration (100, 200, 300 ppm) were examined. The results proved the efficiency of almost all of these isolates in repressing the pathogen growth except endophytic B. bassiana, the effect was not clear. This study revealed that wild plants are a good source of many endophytic fungal strains that may be exploited in different fields like the biological control field.

Fitness and Predating Potential of Antilochus coquebertii (Hemiptera: Pyrrhocoridae): A Predator of the Red Cotton Bug (Dysdercus koenigii)

Antilochus coquebertii is one of the most important predators of Dysdercus koenigii. The present study examines for the first time the fitness (using age-stage and two-sex life table parameters), morphometrics and predating potential of A. coquebertii fed on the second instar of D. koenigii under laboratory conditions. Results indicate that female adults of A. coquebertii consumed significantly higher numbers of second instar D. koenigii (229.81 ± 14.36) when compared to male adults (118.47 ± 10.77). The body length (16.10±0.40 mm) and width (6.60 ± 0.20 mm) of female adults of A. coquebertii were significantly higher if compared to body length (14.40 ± 0.40 mm) and width (5.80 ± 0.40 mm) of male adults. The developmental period of A. coquebertii from egg to female adult (76.09 ± 3.51 days) was significantly longer than egg to male adult (64.00 ± 1.87 days). The fecundity (number of eggs/female) of A. coquebertii was 108.67 ± 3.67 per female. The intrinsic rate of increase (r) and finite rate of increase (λ) per day of A. coquebertii were recorded with values of 5.87 and 1.06 days, respectively. The gross reproductive rate (GRR) and net reproductive rate (R0) of A. coquebertii were 23.17 offspring and 18.56 offspring/individual, respectively. The information obtained in this study will be useful for the development of future research projects focused on this predator against D. koenigii under natural conditions. Based on our results, we suggest that A. coquebertii will be a good biological control agent against the second instar of D. koenigii in cotton fields.

Assessment of the entomopathogenic nematodes against maggots and pupae of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), under laboratory conditions

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is one of the major insect pests which renders the fruit to become unfit for human consumption. In severe cases, losses may reach up to 100% in some fruit crops. The present study aimed to investigate the pathogenicity of entomopathogenic nematodes (EPNs), Heterorhabditis bacteriophora, H. indica, Steinernema carpocapsae, and S. asiaticum against B. dorsalis maggots and pupae under laboratory conditions. One milliliter of EPNs, having 50, 75, and 100 infective juveniles (IJs) against maggots and 100, 150, and 200 IJs against pupae, were poured into 9 cm Petri dishes with 20 g sterilized soil as supporting media. The highest maggots’ mortality (70%) was obtained after 3 days of application of H. bacteriophora and S. carpocapsae and reached up to (96%) after 9 days. S. asiaticum and H. indica caused 91.16 and 85.87% mortality, respectively, after 9 days post treatment at the highest nematode concentration (100 IJs/ml). Whereas, against the fruit fly pupae, H. bacteriophora caused 69.08% mortality after 9 days at the highest concentration (200 IJs/ml). All nematode species showed high effectiveness against both stages of B. dorsalis. Their application can be further evaluated under field conditions to promote a good biological control of fruit flies for healthier fruit production.

Biotic Factors Responsible for Management the Population Trend of Cabbage Aphid Brevicoryne brassicae L, Inhabiting Canola Plants

The present study was conducted to determine the species composition and seasonal abundance of the prevalent arthropod pests and natural enemies inhabiting canola plantations during 2017 and 2018, growing seasons in Assiut, Upper Egypt. Plant relative susceptibility to cabbage aphid Brevicoryne brassicae L.and effect of the naturally occurring parasitoid species to manage the population trend of this insect pest was evaluated. Data revealed the presence of 14 species belonging to 14 genera, 10 families and 5 orders. Predatory species (Campylomma impicta Wagner and Coccinella undecimpunctata L) were constituted the highest proportion of entomophagous species, while parasitoids were presented by one species only [Diaeretiella rapae (McIntosh)]. The predatory species showed less than 6% dominance and 40% abundance. However, the aphid parasitoid was presented by more than 90% dominance and 60% abundance. Thrips tabaci Lindeman was the highest prevalent phytophagous species, while cabbage aphid B. brassicae ranked the second by less dominance and abundance percentages. Cabbage aphid B. brassicae was found to be active on canola plantations all over both growing seasons. A gradual increase in B. brassicae populations was recorded until the appearance of its peak in March, 5. A gradual decrease in the pest populations was recorded until the end of the season. Bactol cultivar harbored the highest aphid mean numbers (132.47individuals/plant) throughout both seasons of study and classified as susceptible (S) cultivar. Serw 4 and Serw 6 cultivars harbored fewer numbers (98.05 and 85.08 individuals/plant) and classified as low resistant (LR) and moderately resistant (MR) cultivars, respectively. The mean percentage of B. brassicae parasitized by D. rapae during both growing seasons was estimated. Although, the pest populations decreased at mid-March, the parasitism percentages increased until the end of both seasons. The seasonal mean of parasitism percentage recorded 34.76%. Simultaneous decrease of the pest numbers with the increase of its parasitoid confirms the responsibility of D. rapae as a good biological control agent against B. brassicae populations

Biological control of mustard aphid, Lipaphis erysimi (Kaltenbach, 1843) through seven-spotted ladybird beetle, Coccinella septempunctata (Linnaeus, 1758) under laboratory conditions

The research study was conducted at the Entomology Laboratory, Department of Zoology, SALU, Khairpur during, 2017-18. Among biological parameters such as; fecundity, fertility, and egg hatching % of a predator, seven-spotted ladybird beetle were 143, 165 and 86, respectively. Whereas; the results of the biology of seven-spotted ladybird beetle show that the first larval stage took up (4.08) days to develop into a second stage that took up (5.32) days, the third stage (6.80) days and the fourth stage (8.00) days to convert into pupae (6.04) days. The overall female days were observed up to (43.76) and the male (39.36). After hatching, the 1st larval stage consumed up to (2) aphids whereas; the 2nd stage (19), the 3rd larval stage (34) with the 4th stage (48) per day, later on, these larvae were converted into pupal stage thus, the adult stage consumed (40) aphids at per day. The ANOVA showed considerable differences in feeding efficiency of Seven-spotted ladybird beetle on aphids under laboratory conditions at (P<0.05). It is concluded; the ladybird beetle, C. septempunctata is well known as a good biological control agent because of predation in nature that has a short life cycle which is also a good character. Thus, the above-mentioned species can be fruitfully used to minimize the sucking insect pests under mustard crop. Keywords: Biology; Feeding behavior; Predator; Sucking pest http://dx.doi.org/10.19045/bspab.2019.80114

The proportion of blue light affects parasitoid wasp behavior in LED-extended photoperiod in greenhouses: Increased parasitism and offspring sex ratio bias

The increasing use of specific wavelengths involving light-emitting diodes (LEDs) under greenhouses enables to overcome the lack of light during winter months, helping crops photosynthesis or vegetative growth. However, modification of the light environment as well as the photoperiod may also alter directly or indirectly the activity of both beneficial and pest insects that depend on plants. Here, we submitted the parasitic wasp Aphidius ervi and its main host the pea aphid, to 4 ratios of red(R): blue(B) LEDs used to lengthen the photoperiod inside a growth chamber. We recorded the parasitism rate of aphids and the sex ratio of newly emerged wasps to evaluate if A. ervi could remain an efficient biological control agent under modified light environments. We found that increasing the 8 h of photophase to 16 h by supplementing with R/B LEDs increased the daily parasitic activity of the wasp as well as their egg laying behavior. Under the 100R light supplement, about 80% of the emerged adults were males, against 50% under 25R:75B light treatment. These results indicate that A. ervi remains a good biological control agent when the light environment is modified. However, the use of red light to extend the photophase has the potential to negatively affect population dynamics of these parasitoids due to its male-bias impact on the sex ratio.

Biocontrol characteristics of the fruit fly pupal parasitoid Trichopria drosophilae (Hymenoptera: Diapriidae) emerging from different hosts

Trichopria drosophilae (Hymenoptera: Diapriidae) is an important pupal endoparasitoid of Drosophila melanogaster Meigen (Diptera: Drosophilidae) and some other fruit fly species, such as D. suzukii, a very important invasive and economic pest. Studies of T. drosophilae suggest that this could be a good biological control agent for fruit fly pests. In this research, we compared the parasitic characteristics of T. drosophilae reared in D. melanogaster (TDm) with those reared in D. hydei (TDh). TDh had a larger size than TDm. The number of maximum mature eggs of a female TDh was 133.6 ± 6.9, compared with the significantly lower value of 104.8 ± 11.4 for TDm. Mated TDh female wasp continuously produced female offspring up to 6 days after mating, compared with only 3 days for TDm. In addition, the offspring female ratio of TDh, i.e., 82.32%, was significantly higher than that of TDm, i.e., 61.37%. Under starvation treatment, TDh survived longer than TDm. TDh also survived longer than TDm at high temperatures, such as 37 °C, although they both survived well at low temperatures, such as 18 °C and 4 °C. Old-age TDh females maintained a high parasitism rate and offspring female ratio, while they were declined in old-age TDm. Overall, TDh had an advantage in terms of body size, fecundity, stress resistance ability and the parasitism rate compared with TDm. Therefore, T. drosophilae from D. hydei could improve biocontrol efficacy with enormous economic benefits in the field, especially in the control of many frugivorous Drosophilidae species worldwide.

Biological control of Salvinia molesta in South Africa revisited

The aquatic weed Salvinia molesta D.S. Mitch. (Salviniaceae) was first recorded in South Africa in the early 1900s, and by the 1960s was regarded as one of South Africa’s worst aquatic weeds. Following the release of the weevil, Cyrtobagous salviniae Calder and Sands (Coleoptera: Curculionidae) in 1985, the weed is now considered under successful biological control. However, the post-release evaluation of this biological control programme has been ad hoc, therefore, to assess the efficacy of the agent, annual quantitative surveys of South African freshwater systems have been undertaken since 2008. Over the last ten years, of the 57 S. molesta sites visited annually in South Africa, the weevil has established at all of them. Eighteen sites are under successful biological control, where the weed no longer poses a threat to the system and 19 are under substantial biological control, where biological control has reduced the impact of the weed. Since 2008, the average percentage weed cover at sites has declined significantly from 51–100% cover to 0–5% cover in 2017 (R2 = 0.78; P < 0.05). Observations of site-specific characteristics suggest that biological control is most effective at small sites and more difficult at larger and shaded sites. Our findings show that S. molesta remains under good biological control in South Africa, however, some sites require intermittent strategic management, such as augmentative releases of C. salviniae.

Identifying Ant-Mirid Spatial Interactions to Improve Biological Control in Cacao-Based Agroforestry System.

The use of ants for biological control of insect pests was the first reported case of conservation biological control. Direct and indirect community interactions between ants and pests lead to differential spatial pattern. We investigated spatial interactions between mirids, the major cocoa pest in West Africa and numerically dominant ant species, using bivariate point pattern analysis to identify potential biological control agents. We assume that potential biological control agents should display negative spatial interactions with mirids considering their niche overlap. The mirid/ant data were collected in complex cacao-based agroforestry systems sampled in three agroecological areas over a forest-savannah gradient in Cameroon. Three species, Crematogaster striatula Emery (Hymenoptera: Formicidae), Crematogaster clariventris Mayr (Hymenoptera: Formicidae), and Oecophylla longinoda Latreille (Hymenoptera: Formicidae) with high predator and aggressive behaviors were identified as dominant and showed negative spatial relationships with mirids. The weaver ant, O. longinoda was identified as the only potential biological control agent, considering its ubiquity in the plots, the similarity in niche requirements, and the spatial segregation with mirids resulting probably from exclusion mechanisms. Combining bivariate point pattern analysis to good knowledge of insect ecology was an effective method to identify a potentially good biological control agent.