Field Of Biological Control Research Articles

The sky is not the limit: Successful foliar application of Steinernema spp. entomopathogenic nematodes to control Lepidopteran caterpillars

Entomopathogenic nematodes (EPNs) are ubiquitous soil-thriving organisms that use chemical cues to seek and infect soil-dwelling arthropods, yielding various levels of biological control. Going beyond soil application, scientists and practitioners started exploring the option of applying EPNs onto the foliage of crops in attempts to manage leaf-dwelling insect pests as well. Despite some success, particularly with protective formulations, it remains uncertain whether EPNs could indeed survive the phyllospheric environment, and successfully control foliar insect pests. In this context, we tested the potential of commercially produced Steinernema feltiae and S. carpocapsae, two of the most commonly used EPNs in the field of biological control, in controlling Lepidopteran foliar pests of economic importance, i.e. Tuta absoluta and Spodoptera spp. caterpillars as models. We first tested the survival and efficacy of both EPN species against the Lepidopteran caterpillars when applied onto tomato, sweet pepper and lettuce leaves, under controlled conditions and in commercial greenhouse conditions, respectively. Subsequently, we explored the behavioural responses of the EPNs to environmental cues typically encountered in the phyllosphere, and analysed plant volatile organic compounds (VOCs). Our results show that both S. feltiae and S. carpocapsae successfully survived and infected the foliar caterpillars, reaching similar level of control to a standard chemical pesticide in commercial practices. Remarkably, both EPN species survived and remained effective up to four days in the phyllosphere, and needed only a few hours to successfully penetrate the caterpillars. Interestingly, S. feltiae was attracted to VOCs from tomato plants, and tended to prefer those from caterpillar-induced plants, suggesting that the nematodes may actively forage toward its host, although it has never been exposed to leaf-borne volatiles during its evolution. The present study shows the high potential of steinernematids in managing major foliar pests in greenhouses and in becoming a key player in foliar biological control. In particular, the discovery that EPNs use foliar VOCs to locate caterpillar hosts opens up new opportunities in terms of application techniques and affordable effective doses.

Circumscription of the Ganaspis brasiliensis (Ihering, 1905) species complex (Hymenoptera, Figitidae), and the description of two new species parasitizing the spotted wing drosophila, Drosophila suzukii Matsumura, 1931 (Diptera, Drosophilidae)

Based on host specificity and distribution data, it has been hypothesized that Ganaspis brasiliensis (Ihering, 1905), a natural enemy of the horticultural pest spotted-wing drosophila, Drosophila suzukii Matsumura, 1931 (SWD), was composed of multiple, cryptic species. Parasitoid wasps assigned to the species name Ganaspis brasiliensis and Ganaspis cf. brasiliensis were investigated using a molecular dataset of ultra-conserved elements (UCEs) and morphology. We report strong evidence for the presence of cryptic species based on the combination of UCE data (1,379 UCE loci), host specificity, ovipositor morphology, and distribution data. We describe these new cryptic species as: Ganaspis lupinisp. nov., and Ganaspis kimorumsp. nov.Ganaspis lupini was formerly recognized as Ganaspis brasiliensis G3, and Ganaspis kimorum as Ganaspis brasiliensis G1. These two new species appear to be restricted to the temperate climates, whereas Ganaspis brasiliensis (formerly recognized as Ganaspis brasiliensis G5) has a more pan-tropical distribution. We investigated the characterization of the ovipositor clip of these species, and hypothesize that G. kimorum, which has a reduced ovipositor clip, has an advantage in ovipositing into fresh fruit, still on the host plant, while attacking SWD; as a corollary, G. brasiliensis and G. lupini, which both have a larger ovipositor clip, are better adapted to attacking hosts in softer, rotting fruit on the ground. As Ganaspis kimorum was authorized for release as a biological control agent against SWD under the name Ganaspis brasiliensis G1, the results here have direct impact on the field of biological control.

Optimization of the fermentation media and growth conditions of Bacillus velezensis BHZ-29 using a Plackett-Burman design experiment combined with response surface methodology.

Bacillus velezensis occurs extensively in the soil environment. It produces a range of antimicrobial compounds that play an important role in the field of biological control. However, during the actual application process it is often affected by factors such as the medium formulation and fermentation conditions, and therefore biocontrol measures often do not achieve their expected outcomes. In this study, the B. velezensis BHZ-29 strain was used as the research object. The carbon and nitrogen sources, and inorganic salts that affect the number of viable bacteria and antibacterial potency of B. velezensis BHZ-29, were screened by a single factor test. A Plackett-Burman design experiment was conducted to determine the significant factors affecting the number of viable bacteria and antibacterial potency, and a Box-Behnken design experiment was used to obtain the optimal growth of B. velezensis BHZ-29. The medium formula that produced the highest number of viable bacteria and most antibacterial substances was determined. The initial pH, temperature, amount of inoculant, liquid volume, shaking speed, and culture time were determined by a single factor test. The factors that had a significant influence on the number of viable bacteria of B. velezensis BHZ-29 were selected by an orthogonal test. A Box-Behnken design experiment was conducted to obtain the optimal fermentation conditions, and highest number of viable bacteria and antibacterial titer. Molasses, peptone, and magnesium sulfate had significant effects on the viable count and antibacterial titer of B. velezensis BHZ-29. The viable count of B. velezensis BHZ-29 increased from 7.83 × 109 to 2.17 × 1010 CFU/mL, and the antibacterial titer increased from 111.67 to 153.13 mm/mL when the optimal media were used. The optimal fermentation conditions for B. velezensis BHZ-29 were as follows: temperature 25.57°C, pH 7.23, culture time 95.90 h, rotation speed 160 rpm, amount of inoculant 2%, and liquid volume 100 ml. After the optimization of fermentation conditions, the number of viable bacteria increased to 3.39 × 1010 CFU/mL, and the bacteriostatic titer increased to 158.85 mm/ml.The plant height and leaf number of cotton plants treated with BHZ-29 fermentation broth were higher than those of cotton inoculated with Verticillium dahliae. The number of bacteria was 1.15 × 107 CFU/g, and the number of fungi was 1.60 × 105 spores/g. The disease index of the cotton seedlings treated with the optimized fermentation broth was 2.2, and a control effect of 93.8% was achieved. B. velezensis BHZ-29 could reduce the disease index of cotton Verticillium wilt and had a controlling effect on the disease. The best effect was achieved in the treatment group with an inoculation concentration of 2 × 108 CFU/ml, the disease index was 14.50, and a control effect of 84.18% was achieved. The fermentation process parameters of the number of viable bacteria and antibacterial titer by strain B. velezensis BHZ-29 were optimized to lay a foundation for the practical production and application of strain B. velezensis BHZ-29 in agriculture.

Anti-aging effect of glycerophosphocholine in Steinernema kraussei 0657L.

Glycerophosphocholine (GPC) is a water-soluble small molecule found naturally in humans and foods such as milk and soybeans. It can activate the IIS pathway by regulating the expression of daf-2, ins-18 and daf-16 genes, sek-1 and skn-1 genes of MAPK pathway, sod-3, ctl-1, gst-4 and other antioxidant genes. GPC can relieve symptoms related to aging in organisms. The aim of this study was to probe the effects of GPC on the longevity and stress resistance of the entomopathogenic nematode (EPN) Steinernema kraussei 0657L strain. The results showed that the lifespan of S. kraussei 0657L was significantly prolonged by 50mM GPC treatment, which was 54.55% longer than that of the control (0mM GPC). GPC significantly inhibited reactive oxygen species (ROS) and lipofuscin accumulation, but the body size and fecundity of S. kraussei 0657L had little changed. At the same time, the longevity of S. kraussei 0657L exposed to heat shock and UV-B radiation was significantly prolonged than that with no external stress. GPC supplementation increased the activity of antioxidant enzymes and corresponding gene expression. Under treatment with 50mM GPC, the activities of superoxide dismutase and catalase were increased by 1.90- and 4.13-fold, respectively, the expression of the sod-3 and ctl-1 genes was increased by 3.60- and 0.60-fold, respectively, and harmful reactive oxygen species were removed. In addition, the expression levels of the ins-18, skn-1, sek-1 and gst-4 genes related to the insulin/IGF-1 signaling pathway were upregulated 1.04-, 1.84-, 2.21- and 1.24-fold, respectively. These results indicate that GPC is mainly involved in the lifespan regulation of S. kraussei 0657L and plays an important role in resistance to external stress by activating the insulin/IGF-1 signaling pathway and downstream PI3K/MAPK kinase, creating a new idea for improving the commercial efficacy of S. kraussei. It also laid a theoretical foundation for its further efficient development and utilization in the field of biological control.

Study on the Multi-Point Boundary Value Problem for Second-Order Nonlinear Impulsive Integro-Differential Equation

In the field of biological control, there are a large number of systems that gradually evolve over a certain period of time. However, due to some natural or human intervention behavior, the system state will be subjected to some relatively short time interference, so that the system state changes in an instant. This sudden change of state makes the system not simply described by continuous or discrete dynamical systems, but by means of impulse dynamical systems. In this paper, the multi-point boundary value problem of a class of second-order nonlinear impulsive integral differential equations is studied on the basis of impulsive differential equation theory. The main results of this kind of equation are obtained by using the fixed point theorem of strict set contraction operator. Under certain assumptions, the existence of the solution of the equation is proved by constructing the operator on the special cone. Finally, combined with the practical application, the theory was applied to the stability prediction of biological ecosystem, and the correctness of the conclusion was verified.

Additive effect of the Streptomyces albus XJC2-1 and dimethomorph control pepper blight (Capsicum annuum L.).

Pepper blight, caused by Phytophthora capsici, is a destructive soilborne disease, which poses a serious threat to pepper, Capsicum annuum L., production. Chemical fungicides, which mainly are used to control pepper blight, have a negative effect on the environment, rendering biological control as a promising alternative to maintain the balance between ecology and pest management. The purpose of this study was to screen the biocontrol bacteria, reduce the dosage of fungicides and increase the stability of biocontrol bacteria, and to find the mixing ratio of biocontrol bacteria and fungicides giving the best control effect. We isolated actinomycetes strains from the soil surrounding the roots of healthy pepper plants amongst field-grown plants infected with P. capsici. Of these, Streptomyces albus XJC2-1 showed a strong inhibition effect on the growth of P. capsici, with an inhibition rate of ≤85%. XJC2-1 effectively inhibited the formation of sporangium and release of zoospores of P. capsici as well as directly destroyed its hyphae, to achieve the inhibitory effect. Transcriptomic profiling of pepper leaves, postirrigation of plants with the XJC2-1 fermentation broth, revealed upregulation of genes related to the photosynthesis pathway in pepper. Furthermore, XJC2-1 treatment improved the net photosynthetic rate and intercellular CO2 concentration, thereby improving the pepper plant's resistance to pathogens. The combination of XJC2-1 with the fungicide dimethomorph (8 μg mL-1 ) displayed strong synergism in inhibition of P. capsici infection, with a control efficiency as high as 75.16%, thus providing a basis for its application in the field. Our study demonstrated that S. albus XJC2-1 inhibited Phytophthora pathogens from infecting pepper plants and enhanced plant host resistance. The combination of XJC2-1 and dimethomorph displayed a more stable and stronger control effect on pepper blight, showing potential for the future application of XJC2-1 in the field of biological control. © 2023 Society of Chemical Industry.

How mites surprise us

It truly is an honor to be included among the recipients of the James Allen McMurtry Award, bestowed by the Systematic & Applied Acarology Society. I am grateful to Dr. Zhi-Qiang Zhang and the selection committee, and especially to Dr. Maria Minor, who nominated me, wrote the associated biography with Dr. Valerie Behan-Pelletier (Minor & Behan-Pelletier 2022), and recorded my oral presentation. The award was unexpected, since my career as a soil biologist seems rather unrelated to Jim’s field of biological control. But while acarologists occasionally have surprised me, mites do it constantly. One need not look far. Even our follicle mites, which certainly surprised our mid-19th century ancestors by their form and presence, continue to surprise us today: they have the lowest number of protein-coding genes known in arthropods, according to Smith et al. (2022). Having been asked by Dr. Zhang to offer some reflections on my half-century in acarology, I can think of no better premise than to give some examples of the numerous times and ways in which my focal group—oribatid mites—surprised, even astonished me.

Success stories in biological control: Lessons learnt

Globally, several success stories have been documented on classical, augmentative and conservation biological control strategies for managing insect pests and weeds. India too has had its share of successes in the field of biological control. Some examples include the management of the papaya mealy bug through classical biological control, suppression of the sugarcane woolly aphid through conservation biological control, and management of rice pests through augmentation biological control. However, it is a sad state of affairs that biocontrol practices have not been either universally accepted or optimally utilised as per the expectations. There are several hurdles to the uptake of biological control, which include unwieldy regulatory procedures to be followed for international exchange of biocontrol agents and registration of microbial biopesticides; hesitation amongst the commercial units to take up production of biocontrol agents (macrobials and microbials) and lack of active interactions between biocontrol researchers and all other stake-holders including farmers, public, extension workers, regulators and politicians. In this paper, an attempt has been made to compile information on some of the significant success stories in the field of biological control. Based on the lessons learnt from the older biological control success stories, proactive steps have been taken in India to tackle some of the recent invasive pests. The need of the hour is for biocontrol researchers and practitioners to network with economists, social scientists and other relevant stakeholders so that the social, economic and financial value of biological control (primarily based on the success stories) can be clearly defined and accurately quantified and communicated to farmers, commercial units and policymakers, which can lead to increased uptake of this sustainable method of pest management.

A Novel Route for Double-Layered Encapsulation of Streptomyces fulvissimus Uts22 by Alginate–Arabic Gum for Controlling of Pythium aphanidermatum in Cucumber

Damping-off disease due to Pythium aphanidermatum is one of the most harmful diseases of cucumber. One of the critical issues in the field of biological control is the establishment of a link between the beneficial bacteria screened in the laboratory and its industrial application. Therefore, when developing biocontrol agents, it is necessary to study the optimization of mass production conditions and to select a suitable carrier for their final formulation. In this study, an attempt was made to provide a suitable formulation for a Streptomyces fulvissimus Uts22 strain based on alginate–Arabic gum and nanoparticles (SiO2 and TiO2) with a layer-by-layer technique. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies showed that when Arabic gum was added to the composition, an electrostatic interaction occurred between alginate and Arabic gum. The scanning electron microscope image of beads show a cubic shape and good dispersion of microcapsules. The encapsulation efficiency in the prepared formulation was reported to be 94%. The maximum release of bacteria from the capsule was recorded on the 35th day of storage, about 109 CFU/gr. The greenhouse experiments showed that encapsulated bacteria resulted in a 95% reduction in damping-off disease of cucumber and showed more potential effects on increasing plant growth traits than free bacteria. This encapsulation strategy can be considered as a suitable alternative for future applications in the agricultural field.

Biology of Aquatic Insect of Order of Hymenoptera in the World A Systematic Review

The aquatic hymenoptera is a small, little-known group that adapts to the aquatic environment and interacts with water as part of its biological cycle. Aquatic hymenoptera are found in all geographical areas, except Antarctica. In total known species of aquatic Hymenoptera, 150 species from 11 families are recognized. Most of aquatic Hymenoptera species belong to the families of Chalcididae , Eulophidae, Mymaridae, Trichogrammatidae, Scelionidae and Pompilidae. In some family like Pteromalidae, Figitidae , Cynipoidea, Braconidae , Diapriidae , Proctotrupoidea limited number of aquatic genus was seen. Because of their short, dense pubescence on the body and wings and elongated, strongly curved claws they have been successful in life on the fresh water. Most of them are endoparasitoids of immature insects. Although little information is available about aquatic hymenopteran, these insects play an important role in human life. Therefore, knowledge of the biology, physiology and ecology of these insects can be of great help in advancing the field of biological control and its effects on human life.

Pelican–Tilapia interaction in Salton sea: an eco-epidemiological model with strong Allee effect and additional food

The effect of diseases in ecological system is an important issue from mathematical and experimental points of view. We have analysed the dynamic nature of an eco-epidemiological model consisting of susceptible Tilapia fish, infected Tilapia fish and their predator the Pelican birds. Again, the susceptible prey population is subjected to a strong Allee effect. Moreover, the provision of additional food to predator is one of the momentous concepts in the field of biological control. Beddington–DeAngelis-type functional response has been taken to represent the interaction between susceptible prey and predator, whereas predator consumes the infected prey as Volterra-type (Holling type I) functional response. Feeding on infected prey increases the death rate of predator and is regarded to contribute negative growth, whereas consumption of susceptible prey enhances predator growth rate and is regarded to contribute positive growth. It is assumed that the predator population has sufficient resistance power to overcome the effect of environmental toxicants and so they are free from transmission of infection. In this work, we have studied some basic properties, such as non-negativity, uniform boundedness, and stability criteria of all feasible equilibria. The existence of transcritical bifurcations has been observed around the planer equilibrium points taking the mortality rate of predator and transmission rate as bifurcation parameters. Also, we have incorporated gestation delay in the system to examine the changing nature of the delay parameter via Hopf bifurcation. Further, the formulae for direction, period, and the stability of bifurcating periodic solutions have been established. Several numerical simulations are illustrated using MATLAB to validate all the theoretical results.

Thirty Years of Research and Professional Work in the Field of Biological Control (Predators, Parasitoids, Entomopathogenic and Parasitic Nematodes) in Slovenia: A Review

This paper provides the first detailed presentation of research and professional activities in the field of biological control in Slovenia during the period of 1990–2020. It presents information on the important pioneering role of Prof. Dr. Lea Milevoj in biological control research in Slovenia, especially in regard to the inventorying and laboratory rearing of indigenous beneficial organisms, evaluation of the influence of food type on the feeding behaviour of beneficial organisms, participation in the first introduction of a natural enemy within the context of classical biological control in Slovenia, preparation of rules on the biological control of plant pests and publication of the first Slovenian monograph on biological control. The paper also describes the activities of Slovenian researchers in regard to entomopathogenic nematodes, especially related to the assessment of their presence and efficiency in suppressing harmful insects and the identification of indigenous parasitic nematodes associated with economically harmful slugs. The paper also notes some applicative and basic research projects pertaining to parasitoids, especially in terms of their function as natural enemies of aphids, and in regard to predators of harmful insects and mites, especially predatory mites. The main goal of these activities is to implement the use of as many natural enemies as possible in food and ornamental plant production systems to replace the use of plant protection products.

Training needs assessment of agricultural extension change agents in the field of biological control of fruit fly in Sinai Peninsula

BackgroundThe context and purpose of the study. The world has turned to the technology of organic agriculture to obtain safe food and preserve the environment, and there have become many standards that control the production, processing, and circulation of organic products. Egypt has been interested in issuing a law to control organic agriculture, and has adopted a trend toward clean agriculture based on the use of organic fertilizers and bio-control of fruit flies. The research aimed to evaluate extension activities to improve training methods in this area, so as to estimate the level of training needs of agricultural extension agents in the field of biological control of fruit flies, and determine the training methods preferred by them, identify the reasons of weak application of the methods of biological control, identify the problems faced by extension agents to transfer biological control recommendations to farmers, and to identify the relationship between the level of training needs of agricultural extension workers and some independent variables. The methodology of the study depends on theoretical and analytical methods; data were collected by personal interview using questionnaire formsResults: the main findingsThe main findings are summarized as follows:It was found that more than three-quarter of change agents did not receive any training courses in this field, the attendees were low beneficiaries, so they are requiring further training in the field of biological control of fruit flies.There are severe training needs for agricultural extension agents for the methods of biological control of fruit fly in the following: pathogenic nematodes, growth regulators and hormones of reproduction, sterilization of male insects, and pathogenic bacteria.The agricultural extension agents prefer training methods as field visits and practical clarificationThere is a direct and significant relationship between the levels of training needs and age, and there are inverse and significant relationships with experience in training, academic qualification, academic specialization, the duration of service in agricultural work, the duration of service in extension work, and the degree of job satisfaction.Conclusionsa brief summary and potential implication. Potential implication is to improve the extension services based on an assessment of the change agent’s training needs, pay attention to the field demonstration in the training, and repeat it several times, and provide the trainers with auxiliary tools, while providing appropriate conditions for the fieldwork, increase agricultural programs on media broadcast to increase viewing, and support channels with research centers in order to facilitate its adoption and disseminate biological control methods in rural areas.

Isolation and Identification of antifungal metabolite producing endophytic Bacillus subtilis (S17) and its in vitro effect on Colletotrichum falcatum causing red rot in sugarcane

Red rot, a threatening disease of sugarcane caused by fungal pathogen Colletotrichum falcatum Went adversely affect the yield and quality of crop. Therefore, it is important to explore such methods of protection which are organically safe especially with the use of bioagents. Currently, usage of endophytic bacteria as biocontrol agent have been focussed in the field of biological control and enhancement of crop productivity. Hence, this study was centred on endophytic bacteria Bacillus subtilis isolate S17 (identified by 16S rRNA analysis) isolated from the sugarcane stalk tissues. The in vitro study indicated that isolate S17 inhibited the mycelial growth of C. falcatum by 76.22 ± 2.34% in dual-culture antagonism assay. Scanning electron microscopy (SEM) revealed the distortion and destruction in the hyphae of the fungal pathogen by isolate S17. Further investigations proved that the hyphal disorientation was by the secretion of various enzymes (chitinase, β-1,3 glucanase, protease, pectinase, and amylase), inhibitory substances viz., siderophore, ammonia, hydrogen cyanide (HCN) and other volatile as well as diffusible metabolites. The volatile and diffusible metabolites exhibited strong inhibition (74.57 ± 1.45% and 81.86 ± 2.36%) against C. falcatum, respectively. Similarly, cell-free culture supernatant that contains extracellular metabolites exhibited mycelial inhibition (70.52 ± 0.95%) against C. falcatum. Thus, the present finding revealed that different metabolites as well as various exo-enzymes produced by B. subtilis (S17) inhibit red rot pathogen besides mechanism of the antagonism.

A novel trehalosamine isolated from Bacillus amyloliquefaciens and its antibacterial activities

Bacillus amyloliquefaciens has been widely used as a probiotic in the field of biological control,and its antibacterial compounds plays an important role in the prevention and control of plant, livestock and poultry diseases. It has the advantages of green, safe and efficiency. This study aims to separate and purify active ingredient from Bacillus amyloliquefaciens GN59 and study its antibacterial activity. A novel compound was isolated from GN59 by column chromatography on silica gel and HPLC purification. The chemical structure was identified as α-d-glucopyranosyl-(1 → 1′)-3′-amino-3′-deoxy-β-d-glucopyranoside (a,β-3-trehalosamine) on the basis of spectroscopic analysis. This is the first report about a,β-3-trehalosamine isolated from biological resources on an antibiotic activity against pathogenic bacterium. The 3′-neotrehalosamine displayed antibacterial activity across a broad spectrum of microorganisms, including different gram-positive and gram-negative bacteria, with minimal inhibitory concentration (MIC) values ranging from 0.5 to 0.7 mg/mL. The results indicated that the 3′-neotrehalosamine from GN59 might be a potential candidate for bactericide.

Estimated divergence times of Hirsutella (asexual morphs) in Ophiocordyceps provides insight into evolution of phialide structure

BackgroundHirsutella Pat genus, the asexual morphs of the Ophiocordyceps Sung, is globally distributed entomopathogenic fungi, which infect a variety of arthropods, mites and nematodes. The fungal species also have shown potential application in the field of biological control, bio-medicine and food development. Although these fungi are synonymized under Ophiocordyceps, formal taxonomic assignments remain necessary for classification of species in Hirsutella. However, due to the heterogeneity and complexity of Hirsutella genus, more detailed taxonomic and phylogenetic analyses are required to address the following subjects: (1) the relationships between the phialide morphological characteristics and phylogenetic information of Hirsutella with asexual morphs, (2) the origin and evolution of the phialide structure, and (3) host specificity and fungal pathogenicity.ResultsFive typical phialide structures are summarized, in which the variation in phialide characteristics overlaps well with phylogenetic information. A new member of the special twisted neck clade in the Hirsutella-like group, Ophiocordyceps retorta, was reported based on these analyses. The molecular clock calibration analysis based on one fossil record revealed that Hirsutella (asexual morph) species originated from a common ancestor approximately 102 million years ago (Mya) (Early Cretaceous, Lower Albian) and then resolved into two major lineages. One lineage was typically phialidic, which was a larger shape, including H. guyana, H. nodulosa and H. sinensis clades (86.9 Mya, 95% highest posterior density (HPD): 69.1–101.4 Mya). Another main lineage of the phialides was more diversified and smaller than the former, which included H. citriformis and H. thompsonii clades (71.9 Mya, 95% HPD: 41.8–99.6 Mya).ConclusionsOur results showed that certain phialide characteristics of Hirsutella were phylogenetically informative for two groups of taxa. The differentiation of the phialides structures in the major clades demonstrated a clear evolutionary path of Hirsutella (asexual morph) species, which exhibited two trends depending on the host size. Fungi in one of the groups displayed elongated conidiogenous cells with increased complexity of auxiliary structures from the mycelia. The species in another group reduced the volume of phialides and spores, which might be due to an energy-efficient strategy. These results suggested that a common origin allowed for diversification of given clades into separate niches. The distinct parallel evolutionary path combined with the specific phialides structure might result in the host specificity of Hirsutella (asexual morphs). A direct relationship between Hirsutella (asexual morphs) and the Cretaceous–Tertiary extinction was not found, which suggested that the diversity of phialides is more likely to be caused by long-term environmental adaptation and evolution rather than dramatic extinction events. This evolutionary result might correspond to the background of important biological and geological events in the late Cretaceous occurring near the divergence times of Hirsutella (asexual morphs).

KNOWLEDGE LEVEL OF AGRICULTURAL EXTENSIONISTS IN THE FIELD OF BIOLOGICAL CONTROL IN ISMAILIA GOVERNORATE

The aim of the research were to determine knowledge level ofagricultural Extensionists in the field of Biological Control, identify trainingmethods which preferred by agricultural Extensionists for training in the fieldof Biological Control, identify reasons for farmers 'reluctance to applyBiological Control methods from the point of view of the Extensionists, anddetermining the relationship between the studied variables and the knowledgelevel of the agricultural Extensionists in the field of Biological Control.Research was conducted on a random sample of 95 agricultural Extensionistsin Ismailia Governorate. Data were collected by a questionnaire in January2017, frequency, percentage, weighted average, Pearson's simple correlationcoefficient, Chi square were used to analyse data.The main findings of the research were as follows:1. More than three froths of the respondents (76.8%) of the agriculturalExtensionists did not receive training in the field of Biological Control. 8.4%and 14.7% of them had low and average benefit.2. about four fifths of the respondents (78.9%) had low knowledge ofBiological Control, compared with 4.3% have high level of knowledge.3. Agricultural Extensionists prefer the following methods of training in thefield of Biological Control: field visits, practical demonstration, and seminars.4. Reasons of reluctance of farmers to use the Biological Control from thepoint of view of respondents: Lack of knowledge and information of farmersabout the methods of biological control, lack of requirements for theapplication of biological control, weak shortage of communication challengesbetween research centers and agricultural extension and farmers.5. The most important problems faced respondents in the field of biologicalcontrol were: lack of incentives and rewards, shortage of extension programson Biological Control, lack of extension aids.6. There is a significant relationship between the following variables: age,academic qualification, academic specialization, length of service in extensionwork, training, the degree of job satisfaction, and knowledge level of theextensionists in the field of Biological Control.

Evaluation of the effects of some insecticides based on neonicotinoids on entomopathogenic nematodes, Steinernema feltiae and S. carpocapsae

Used of entomopathogenic nematodes (EPNs) are one biological control way against some insect pests, which especially pass one stage of their life in the soil. There have been a lot of developments and new discoveries in the field of entomopathogenic nematology. In spite of developments in the field of biological control, pesticides are still widely used for plant protection. These pesticides have side effects on soil biotop such as EPN species. In this study, we evaluated the effects of two insecticides (acetamiprid and imidacloprid) belong to neonicotinoid group on two EPNs (Steinernema carpocapsae and Steinernema feltiae). The present experiments were carried out in the laboratory. Mortality rate of the EPN species was performed at 24, 48 and 96 h, after treatment. Inspired by the compatibility observed between the neonicotinoid insecticides and EPNs against insect pest larvae, it was evaluated the direct effects of those insecticides on EPNs. Our results showed less mortality by imidacloprid and mortality rates are a little higher by acetamiprid. These results confirm the high compatibility of imidacloprid with EPNs and the low synergism with acetamiprid. Despite their effects on pollinators and other useful organisms of the biotop, these insecticides can be used effectively against soil dwelling insect pests without high risk on EPNs.

Relationship of microbial communities and suppressiveness of Trichoderma fortified composts for pepper seedlings infected by Phytophthora nicotianae.

The understanding of the dynamic of soil-borne diseases is related to the microbial composition of the rhizosphere which is the key to progress in the field of biological control. Trichoderma spp. is commonly used as a biological control agent. The use of next generation sequencing approaches and quantitative PCR are two successful approaches to assess the effect of using compost as substrate fortified with two Trichoderma strains (Trichoderma harzianum or Trichoderma asperellum) on bacterial and fungal communities in pepper rhizosphere infected with Phytophthora nicotianae. The results showed changes in the bacterial rhizosphere community not attributed to the Trichoderma strain, but to the pathogen infection, while, fungi were not affected by pathogen infection and depended on the type of substrate. The Trichoderma asperellum fortified compost was the most effective combination against the pathogen. This could indicate that the effect of fortified composts is greater than compost itself and the biocontrol effect should be attributed to the Trichoderma strains rather than the compost microbiota, although some microorganisms could help with the biocontrol effect.

Effects of different host species on the life history of Bracon hebetor

Bracon hebetor(Hymenoptera: Braconidae) is a generalist idiobiont ecto-parasitoid that parasitizes a wide range of Lepidoptera and even some phylogenically distant weevil species (Coleoptera; Curculionidae). In the present context, our aim is to find the most suitable host for efficient laboratory rearing ofB. hebetor. We compared fitness traits of this parasitoid wasp on five host species, four species belonging to the Lepidoptera, viz.Galleria mellonella(Pyralidae),Helicoverpa armigeraandSpodoptera litura(Noctuidae),Sitotroga cerealella(Gelechiidae), and one to the Coleoptera, the alfalfa weevilHypera postica(Curculionidae). We determined the parasitic potential, paralysis, daily oviposition rate, development time, total adult progeny, sex ratio and survival. Fecundity was followed during five consecutive days and oviposition period was determined, all under laboratory conditions. The best results were obtained on the wax moth larvae (G. mellonella) for whichB. hebetorproved the highest biological activity in term of paralysis, parasitism and oviposition as compared to other tested host species. InGalleria mellonella, total eggs laid per female per five days and egg-adult survivorship were higher and sex ratio was highly biased toward females, as compared toHypera postica. Intermediate biological activities were found onHelicoverpa armigera,Spodoptera lituraandSitotroga cerealella. These contrasting results show that the plasticity of this species could also represent an important fitness cost difference in performance, which is discussed in terms of phylogenetic distance of the host species (particularly Pyralidae). In conclusion, the possible application of these results can be used in the economically important field of biological control and improve storage of products affected by insect pests.