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The literature posits that an introduced predator population is able to drive its target pest population to extinction, if supplemented with high quality additional food of sufficient quantity. We show this approach actually leads to infinite time blow-up of the predator population, so is unpragmatic as a pest management strategy. We propose an alternate model in which the additional food induces predator competition. Analysis of this model indicates that depending on the competition parameter $c$, one can have global stability of the pest-free state, bistability dynamics, or up to three interior equilibria. As $c$ and the additional food quantity $\xi$ are varied standard codimension one and codimension two bifurcations are observed. We also use structural symmetries to construct several nonstandard bifurcations such as saddle-node-transcritical bifurcation (SNTC) in codimension two and a cusp-transcritical bifurcation (CPTC), also in codimension two. We further use symmetry to construct a novel pitchfork-transcritical bifurcation (PTC) in codimension two, thus explicitly characterizing a new organizing center of the model. Our findings indicate that increasing additional food in predator–pest models can hinder bio-control, contrarily to some of the literature. However, additional food that also induces predator competition, leads to rich dynamics and enhances bio-control.

In this study, we extend the two-dimensional host–parasitoid model to a one-host–two-parasitoid model, whose dynamic behaviors are more complex. As evidence, exploring the dynamic interaction between a host and its parasitoids provides significant insight into the biological control. Specifically, we demonstrate the existence of equilibrium points and explore their local stability properties, which are concerned with the effective biological control project. Furthermore, the transition between population fluctuations and the steady state is achieved via a bifurcation process, and we derive the occurrence conditions of the Neimark–Sacker bifurcation in the proposed system using an explicit criterion. To control population fluctuations and chaotic behaviors, two feedback control strategies are implemented in this system. Finally, the numerical simulations support our theoretical results and show the related biological phenomena.

The generalized Gause model of predator-prey system is revisited with an introduction of viral infection on prey population. Stability behavior of such modified system is carried out to observe the change of dynamical behavior of the system. To substantiate the analytical results of this generalized susceptible prey, infected prey and predator population, numerical simulations of the model with specific growth and response functions are performed. Our observations suggest that the disease on prey population has a destabilizing or stabilizing effect depending on the level of force of infection and may act as a biological control for the persistence of the species.

The efficacy of biological control of Aedes aegypti mosquitoes using Sterile Insect Technique (SIT) is analyzed. This approach has shown to be very efficient on agricultural plagues and has become an alternative control strategy to the usual technique of insecticide application, which promotes resistance against chemical controls and is harmful to other species that live in the same mosquito habitat. By using a discrete cellular automata approach we have shown that in the case of Aedes aegypti, the spatially heterogeneous distribution of oviposition containers and the mosquito behavior, especially with respect to mating, make the application of STI difficult or impracticable.

The harmful effects of insect pests on human health and agricultural output are a major global concern. Frequent use of chemical pesticides as a means of pest control can have detrimental effects on the environment, resulting in water and soil pollution, food toxicity, resistance to pesticides, etc. As a result, there is an urgent need to develop a biological pest-control approach that would mitigate these harmful effects. The main purpose of the present study is to explore the interaction between strong Allee effects in the pest with other biological control mechanisms, such as providing additional food to the predator and pest culling as a means of proposing an efficient pest-control policy. To achieve this goal, local stability analysis around the equilibria, possible bifurcation and some basic dynamical features of the system was performed. Our work focuses on the basin of stability in multiple stable regions of the model, which yields the probability of convergence of each equilibrium for a given set of different initial conditions. The system exhibits bi-stability and tri-stability of the equilibria. Our findings indicate that providing additional food to the predator can be an efficient stand-alone pest control strategy, which can, if needed, be combined with other methods.

Recently, pest control has become a very interesting research topic because it is closely associated with agricultural and economic loss. Empirical evidence shows that pest insects are responsible for lower crop production and many other adverse effects on the farming sector. There are several biological, physical and chemical control mechanisms. However, the biological control of pest populations by using natural enemies is one of the most important ecosystem services adopted in agriculture around the world. In the present study, we consider an ecological model consisting of prey (pest) and its natural enemy as the predator. Different system equilibria are obtained, their stability is analyzed, and Hopf bifurcation of the system around the interior equilibrium is discussed. The sufficient permanence criteria of the system are also derived. Moreover, we perform bifurcation analysis to explore the existence of limit cycle. We also investigate the stability property of the positive periodic solution when the interior equilibrium loses its stability. Our analytical results are further verified through numerical simulations. Our findings suggest that, in the absence of a super predator, pest and natural enemy show stable coexistence. However, in the presence of super predator, if the natural enemy is killed at a lower rate, both pest and natural enemy coexist. Finally, above a threshold value, the natural enemy is eradicated from the system and pest outbreak occurs.

The Trojan Y Chromosome (TYC) strategy is a biological control method for controlling invasive populations with an XX–XY sex determinism, wherein a modified organism is introduced into an invasive population to skew the sex ratio over time, causing local extinction. However, the classical three compartment TYC model possesses blow-up solutions, for large initial conditions [Takyi EM, Beauregard MA, Griffin T, Bobo L, Parshad RD, On large and small data blow-up solutions in the Trojan Y Chromosome model, Axioms 11(3):120, 2022]. We investigate model improvements via accounting for a modified logistic term, female mating preference, competition between males and supermales and pair formation. Each one of these models is dynamically explored and is shown to possess global in-time non-negative solutions, in any parameter and initial data regime, and the models are also effective in facilitating extinction of the invasive wild type.

In this paper, a classical periodic Lotka–Volterra predator-prey system with impulsive effect is investigated. We analyze the dynamics of positive solutions of such models. Among other results we show that if some trivial or semi-trivial positive solution is linearly stable, then it is globally asymptotically stable with respect to the positive solutions. By using the method of coincidence degree, a set of sufficient conditions are derived for the existence of at least one strictly positive (componentwise) periodic solution. We use bifurcation theorem to show the existence of coexistence states which arise near the sem-trivial periodic solution. As an application, we also examine some special cases of the system which can be used in the biological pest control.

We investigate a three-species food chain system with density-dependent birth rate and impulsive effect concerning biological and chemical control strategy — periodic releasing of natural enemies or spraying pesticide at different fixed times. Conditions for the extinction of the prey and top predator are given. By using the Floquet theory of impulsive differential equations and small amplitude perturbation skills, we consider the local stability of the prey and top predator eradication periodic solution. Further, we obtain the conditions of permanence of the system.

Due to human-caused deforestation, global warming, and other environmental factors, habitat fragmentation became widespread. This fragmentation has a variety of detrimental repercussions for many species as well as humans, especially in the agricultural economy. It causes insect outbreaks, the expansion of alien species, and disrupts biological management by rendering the habitat unsuitable for natural enemies in agriculture. Providing natural enemies with additional food is one method to improve the ecosystem and support them. In this study, we assumed that the ecosystem is separated into two patches and that predators can easily migrate from one patch to the next, while prey stays inside its patch’s territory. We looked at the impact of offering more food to predators in a patchy environment using dynamical systems theory. The permanence, stability, and various bifurcations that occur in the system are studied using a rigorous mathematical analysis. The study looks at how predator’s access to other food sources affects pest management. By adjusting the provided food’s characteristic qualities, such as (nutritional) quality and quantity, one can limit and manage the pest in one or both patches, as well as eliminate predators from the ecosystem. This research reveals that providing predators with additional food (of specified quality and quantity) can help in controlling chaotic behavior in the system. The findings of the study are supported by numerical simulations.

The purpose of this research was to study the biocide effect of three agroindustrial subproducts, concretely sugar beet, sugar cane and wine vinasse. Two tests were carried out. The first centred on studying the action of the three agroindustrial subproducts in vitro. In dilutions at initial doses of 1%, 3% and 5%, their performance against six phytopathogenic fungi was analyzed: Fusarium oxysporum f.sp. melonis race 0, Fusarium oxysporum f.sp. melonis race 1, Fusarium oxysporum f.sp. radicis-cucumerinum, Sclerotinia sclerotiorum (as representatives of the Mycetae or Fungi kingdom, whose cell walls contain chitin) and Pythium aphanidermatum and Phytophthora parasitica (as representatives of the Chromista kingdom, whose cell walls contain cellulose). Next, the antagonistic capacity of the solutions assayed in vitro was tested in soil, studying the incidence of the subproducts on the Fusarium populations in these soils.

Results from in vitro testing determined that wine vinasse is what shows a 100% capacity to suppress fungal growth with concentrations that are not very high, between 5% and 7% for Fusarium oxysporum f.sp. melonis race 0, Fusarium oxysporum f.sp. melonis race 1, S. sclerotiorum, P. aphanidermatum and P. parasitica and 10-15% for Fusarium oxysporum f.sp. radicis-cucumerinum. On the other hand, sugar cane vinasse produced an increase at high concentrations and sugar beet vinasse showed an approximate 100% suppressor effect on fungal growth for only some of the phytopathogens tested: S. sclerotiorum (15%), P. aphanidermatum (7%), P. parasitica (15%) and Fusarium oxysporum f.sp. radicis-cucumerinum (15%).

In the soil samples analyzed none of the three vinasse extracts decreased fusaric microbiota, producing an increase in the three samples tested. This would implicitly convey an improvement in soil quality by producing a potential increase in bacterial and fungal microbiota.

Therefore the continuity of this research is necessary, carrying out field experiments so potential lower concentrations can be determined that generate disease suppression in more complex systems.

Penicillium expansum is the major causal agent of postharvest decay in a variety of vegetables and fruits, especially in apples and pears and it is also the main source of the toxin patulin in juices and other derivatives. The activity of certain species to control relevant toxicogenic or phytopathogenic fungi has been described and considered as an interesting feature to be used in integrated strategies to control these fungi. In this study, the antagonist ability of 16 yeast strains from seven different species was tested against 17 P. expansum strains isolated from apples of different locations. The strains Debaryomyces hansenii CYC 1244 and CYC 1021 showed the strongest inhibitory activity in plate against all the P. expansum strains. Additional biocontrol assays in apples were performed with D. hansenii CYC 1244 at 4°C, 15°C and 25°C. Rot caused by P. expansum in apples was reduced between 30-50% at 25°C and around 75% at 4°C.

The crystal morphology and Cry protein composition of twelve Cuban Bacillus thuringiensis (Bt) strains were analyzed. Their in vitro biological activities were evaluated against Spodoptera frugiperda, Anticarsia gemmatalis and eggs of the nematode Meloidogyne incognita. The scanning electron micrographies as well as the morphology, size and number of the inclusions showed variations amongst the different strains, as expected. The Cry protein SDS-PAGE profile showed proteins of 130 kDa and 70 kDa. The bioassays showed two Bt strains highly active against S. frugiperda and A. gemmatalis, and six strains interrupted the development of nematode egg´ mass. There were different behaviors regarding nematode infectivity but all of them resulted in nematostatic and disorientation effects under the experimental conditions. Based on the results obtained the two most virulent strains will be further studied for mass production and formulation as a biopesticide.