Biological Control Research Articles

Direct and indirect effects of selective insecticides on 2 generalist predators of Bemisia tabaci (Hemiptera: Aleyrodidae).

Generalist arthropod predators have historically contributed to the suppression of arthropod pests in many agroecosystems. The successful implementation of integrated pest management (IPM) programs hinges on the incorporation of insecticides that are compatible with the biological attributes of natural enemies of pests. A potentially promising pathway is improving biological control by natural enemies through the timely application of selective insecticides. In our study, adult predators were exposed to commercially available insecticides (cyantraniliprole and pyriproxyfen) using a combined laboratory and field approach to assess their effects on survivorship and predation. We isolated 2 predators, Hippodamia convergens Guérin-Méneville and Geocoris punctipes (Say), in the laboratory to estimate the survivorship and consumption of whitefly nymphs, Bemisia tabaci (Gennadius). In the field, we deployed whitefly nymph-infested potted cotton plants in replicated cotton plots with both insecticide treatments. We enumerated whitefly nymph populations on enclosed (predator-exclusion) and open (predator-accessible) potted plants. While pyriproxyfen had a negligible effect on the predators, cyantraniliprole exposure directly affected H. convergence by reducing survivorship duration and indirectly influenced both predators by reducing prey consumption and altering the consumption of alternative prey. In field conditions, regardless of pesticide exposure, whitefly-infested potted plants that excluded predators had more whiteflies than predator-accessible potted plants. Overall, pyriproxyfen demonstrated minimal impact on the predators in the laboratory or field, while cyantraniliprole adversely influenced mortality and indirect foraging under controlled laboratory conditions but did not have a significant impact in the field.

Aerial Systems for Releasing Natural Enemy Insects of Purple Loosestrife Using Drones

Lythrum salicaria (purple loosestrife) is an invasive species that displaces native wetland flora in the USA. The detection and manual release of biological control agents for L. salicaria is challenging because L. salicaria inhabits many inaccessible areas. This study was conducted to develop aerial systems for the detection of L. salicaria and the release of its natural enemy, Galerucella calmariensis (Coleoptera: Chrysomelidae). We determined the optimal sensors and flight height for the aerial detection of L. salicaria and designed an aerial deployment method for G. calmariensis. Drone-based aerial surveys were conducted at various flight heights utilizing RGB, multispectral, and thermal sensors. We also developed an insect container (i.e., bug ball) for the aerial deployment of G. calmariensis. Our findings indicated that L. salicaria flowers were detectable with an RGB sensor at flight heights ≤ 15 m above the canopy. The post-release mortality and feeding efficiency of G. calmariensis did not significantly differ from the control group (non-aerial release), indicating the feasibility of the targeted release of G. calmariensis. This innovative study establishes a critical foundation for the future development of sophisticated aerial systems designed for the automated detection of invasive plants and the precise release of biological control agents, significantly advancing ecological management and conservation efforts.

Suppression of Thielaviopsis ethacetica wilt and root rot, the emerging pathogen on bell pepper (Capsicum annuum), and plant growth promotion properties by the safety indigenous Streptomyces SBcT04

Thielaviopsis ethacetica is an emerging pathogen responsible for wilt and root rot in bell peppers, significantly impacting crop yield. Biological control of the fungal pathogen provides significant advantages as a safe and efficient alternative to excessive chemical fungicides for managing plant diseases. Studying the screened and selected potential actinomycete strain from the indigenous collection is a quick and efficient measure to protect the yield of local bell pepper crops. The research assessed the indigenous actinomycete's ability to inhibit plant pathogens and promote plant growth both in vitro and in vivo. The Streptomyces SBcT04 was the most effective against T. ethacetica TROC-2 pathogen in vitro. The inhibition percentage reached 89.15 ± 0.46 %. SBcT04 also effectively promoted plant growth properties in vitro. This strain fixed nitrogen and produced substantial amountsof indole-3-acetic acid (IAA), siderophores, and enzymes. Furthermore, the safety characteristics of SBcT04 for both the host plant (in vivo) and animals (in vitro) were confirmed. Streptomyces SBcT04 significantly processed pathogens, resulting in a reduction of approximately 40 % in disease severity. Additionally, SBcT04 significantly promoted the host plant's growth, even in the presence of T. ethacetica TROC-2 infection. The indigenous Streptomyces SBcT04 efficiently inhibited T. ethacetica and significantly enhanced bell pepper plant growth. These advantageous characteristics of SBcT04 indicate its potential to foster secure and sustainable local bell pepper agricultural output.

Phylogenetic analysis of Syrphidae (Insecta, Diptera) based on low-coverage whole genomes

Abstract The hoverflies are one of the most abundant families in Diptera and an important category of resource insects. They can provide important ecosystem services such as pollination and beneficial biological control agents. In the four-subfamily classification system of the Syrphidae, the monophyly of the Eristalinae within Syrphidae has not been recovered. In this study, we performed new sequencing and analysis of low-coverage whole genomes for 25 species of Syrphidae. Phylogenetic reconstructions were conducted based on different datasets and analytical strategies. Across all our analyses, the monophyly of the Syrphinae is supported but we do not recover the monophyly of the Eristalinae, consistent with previous research findings. Additionally, employing fossil calibrations for divergence time estimation, our results indicate that the origin of the Syrphidae occurred between the Albian and Aptian stages, approximately between 120.5 and 109.3 million years ago, the origin of the subfamily Syrphinae was dated in the Early Eocene, about 50.8–47.8 million years ago, in accordance with the diversification of their prey. This study will help us understand the higher-level phylogenetic and evolutionary relationships within Syrphidae.

Morphology of the Mouthparts of Ladybeetle Vibidia duodecimguttata (Coleoptera: Coccinellidae), with Emphasis on Their Sensilla.

Mouthparts are the feeding organs of insects, which play vital roles in the feeding process. The morphology of insect mouthparts has greatly evolved according to different foods and feeding habits. Therefore, studying the structure of the mouthparts is the key to understanding their feeding mechanisms. Vibidia duodecimguttata is an important biological control agent for powdery fungus. In this study, the fine morphology of the mouthpart of V. duodecimguttata was studied by scanning electron microscopy. The basic components of mouthpart of V. duodecimguttata are similar to those of other ladybeetles, while the specific morphology of each part is different. In total, six kinds of sensilla were identified on mouthpart, and twelve types of sensilla were divided according to their morphology, length and distribution. In addition, two kinds of glandular structures were also found, namely perforated plates and cuticular pores. Finally, the morphological differences between mycetophagous and other feeding habits ladybeetles were compared, and the function of each kind of sensilla was discussed, which may establish a solid foundation for further understanding of the feeding mechanism of ladybirds.

Forecasting Western Corn Rootworm (Diabrotica virgifera virgifera LeConte) Density and Non-Chemical Control of Larvae: A Practical Review

The western corn rootworm (WCR) (Diabrotica virgifera virgifera LeConte; Chrysomelidae) is one of the most significant maize pests in Europe, with farmers spending a substantial amount (approximately 140 EUR) on its control. In the context of climate change, WCRs could pose an even greater threat to EU maize production, particularly as the European Union continues to withdraw an increasing number of effective yet environmentally harmful active agents. Biological control methods have now emerged to the forefront in creating sustainable agriculture. In this review, we carried out an extensive literature analysis on methods for forecasting WCRs and evaluated the practical applicability of the latest non-chemical control methods targeting its larvae. Effective forecasting is essential for successful pest management, enabling informed planning and the selection of the most suitable control methods. Several traditional predicting techniques remain in use today, but recent advancements have introduced modern electronic forecasting units combined with sensor-equipped pheromone and colour traps, as well as thermal sum calculations. Research has demonstrated that crop rotation is one of the most effective methods for controlling WCR larvae. Biological agents, such as entomopathogenic fungi (Beauveria bossiana and Mettarrhyzum anasoplia), entomopathogenic nematodes (Heterorhabditis bacteriophora), and botanical insecticides such as azadirachtin can significantly reduce larval populations and root damage, thereby maintaining infestation levels below the economic threshold. Genetically modified maize plants that produce specific toxins, along with conventional breeding efforts to increase root system regeneration, are also promising tools for the sustainable management of this pest. This review summarizes the solutions for prediction of western corn rootworm infestations and non-chemical control of its larvae. Accurate forecasting methods provide a clear picture of infestation levels in a given area, enabling precisely targeted control measures. In all cases, the control should be directed primarily against the larvae, thereby reducing root damage and reducing the size of the emerging imago population. This review demonstrates that biological control methods targeting larvae can be as effective as pesticides, supporting sustainable pest management.

Structure and Fungicidal Activity of Secondary Metabolites Isolated from Trichoderma hamatum b-3.

Two new harziane diterpenes (1-2), five undescribed cyclonerane sesquiterpenes (3-7), and three known compounds, 11-cycloneren-3, 7, 10-triol (8), harziandione (9), and dehydroacetic acid (10), were isolated from Trichoderma hamatum b-3. Their structures were elucidated via comprehensive inspection of spectral evidence in HRESIMS and 1D and 2D NMR, and the absolute configuration of 1-8 was confirmed by NMR, ECD calculation, as well as Mosher's method. In vitro fungicidal activity showed that some compounds showed great inhibitory activity against pathogenic fungi, including Fusarium graminearum, Sclerotinia sclerotiorum, Botrytis cinerea, and Rhizoctonia solani, among which compound 10 showed 100% inhibition of S. sclerotiorum and B. cinerea. The in vivo activity test showed that compound 10 was 65.8% effective against B. cinerea and compound 10 can be used as a lead compound for the development of biopesticides that inhibit B. cinerea. This study elucidated the bioactivity of secondary metabolites of T. hamatum and indicated the direction for the subsequent development of the biological control activity of T. hamatum.

High Prevalence of Sarcocystis in a Collapsed Black Rat (Rattus rattus) Population from the Florida Keys.

We collected and screened black rats (Rattus rattus) in Key Largo, Florida, USA, to determine the potential role of disease or parasites in the collapse of the local population. Rats appeared healthy, but 94% (n=15/16) tested positive for Sarcocystis sp. The partial 18S rRNA gene sequence was 98.7-99.7% similar to a strain of Sarcocystis zuoi that is now considered a strain of the newly described Sarcocystis kani within the larger S. zuoi species complex that contains numerous new species. These Sarcocystis spp. use Asian snakes as definitive hosts and rodents, shrews, or tree shrews as intermediate hosts. Pythons are the definitive host for several Sarcocystis spp. in Asia, including a related parasite (Sarcocystis singaporensis) that has been used as a biologic control agent for Rattus spp. in southeast Asia. It is probable that increasing numbers of invasive Burmese pythons (Python bivittatus) in the Florida Keys are contributing to the spread of this parasite in addition to imposing predation pressure on both rodents and native snakes. As such, further surveillance and molecular and morphologic characterization of parasites from rodents and snakes in south Florida should be prioritized.

Olfactory response to HIPVs and biological aspects of Chrysoperla externa intended for the biological control of Aleurodicus cocois in cashew

ABSTRACT This study evaluates the olfactory response of Chrysoperla externa to the volatiles of the Embrapa 51 genotype of the cashew induced by the herbivory of Aleurodicus cocois, identifies the chemical profile of these compounds and evaluates the development of C. externa fed on A. cocois. The volatiles emitted by the leaves of the cashew genotype, both infested and not infested with A. cocois, were analysed by solid-phase microextraction with GC-MS. In the olfactometry tests, C. externa was attracted to and spent more time in the olfactometer arm containing cashew plant volatiles induced by A. cocois. From the analysis of the volatile profiles, α-phellandrene, α-terpinene, ρ-mentha-2,4(8)-diene, β-caryophyllene and germacrene D were released in large amounts by the Embrapa 51 genotype only after infestation by A. cocois; these compounds may therefore be involved in attracting the predator. Under laboratory conditions, although the development time and survival of some immature stages of C. externa may vary with the type of prey, when fed on A. cocois, the predator is able to complete the egg-adult development cycle. Based on the behavioural and biological assays, C. externa is an effective biocontrol agent for A. cocois in the cashew.

Pathogenic diversity of Puccinia kuehnii strains, causal agent of sugarcane leaf rust and biological control approach using biopesticides under semi-controlled conditions

Context: In Côte d'Ivoire, sugarcane plays an important role in the economy. However, its production is constrained by biotic factors, particularly orange rust caused by Puccinia kuehnii. Pathogenic diversity of strains is not widely understood. Existing control methods are ineffective and limited. The aim of this study was to determine the pathogenicity of Puccinia kuehnii strains, and to evaluate anti-fungal activity of essential oil-based formulations against this disease. Materials and methods: Strains 51bB and 381Z were evaluated for infectivity by foliar spraying plants of variety SP711406 under semi-controlled conditions at the Université Félix Houphouët-Boigny in Abidjan (Côte d'Ivoire). Curative control was carried out by foliar spraying plants with formulations based on natural substances of Ocimum gratissimum L, Zingiber officinale and Cymbopogon citratus, at 1000 and 2000ppm. The synthetic product copper oxide was used at a single dose of 5000 ppm. Results: Strains 51bB and 381Z showed infection rates of 62.26 and 67.36% respectively after a four-month incubation period. Severities of 30.64% (51bB) and 30.23% (381Z) were observed. ZinC1 and ZinC2 treatments had an estimated incidence reduction rate of 64.28%. Treatments based on natural substances achieved a reduction in severity of over 50%. The CymC2 treatment was the most effective, with a reduction rate of 86.04% followed by ZinC1 with rates of over than 50% reduction rate of incidence and severity due to the synthetic product was 50 and 48.83% respectively. Conclusion: Puccinia kuehnii strains induced orange rust disease in sugarcane. The effect of essential oil-based formulations has been proven on the disease under semi-controlled conditions.

Control of Helminth Infections in Captive Herbivores: An Overview of Experience

There are numerous challenges associated with helminth control in captive animals. The aim of the present paper is to provide an overview of the research on deworming of captive herbivorous mammals, the associated problems and the solutions sought, in order to derive recommendations for practice in the relevant institutions. The research was conducted by searching electronic internet databases and following the bibliographies in the published articles. The articles found are presented in summarized form. Most of the results relate to herbivores of the family Bovidae, followed by the families Cervidae, Equidae, Elephantidae, Camelidae and Giraffidae. Systematic data are presented on the types of anthelmintics used, dosages and application regimens for different animal species. Anthelmintics were administered at doses similar to or even higher than those used in farm animals, with no evidence of side effects. Treatment results often depended on the animal and parasite species. Incomplete cure, reinfection, and resistance to anthelmintics were the most common problems in the field. Based on the literature reviewed, the optimal prevention measures include the following: quarantine of newly arrived animals; daily or as intensive as possible cleaning of droppings; regular change of substrate in the enclosures; and monitoring of possible infections and their qualitative and quantitative composition (monthly or at least every two months). For treatments and monitoring effectiveness, recommendations include the following: individual assessment of the need for treatment; selective choice of anthelmintics; post-treatment examination between the 10th and 14th day after deworming; carrying out a group treatment after a preliminary drug effect test; conducting mass deworming only in case of a significant increase in fecal egg counts, highly pathogenic helminth species and a deterioration in the condition of the animals. In the future, more attention should be paid to new approaches such as biological control by saprophytic fungi or natural compounds as an alternative to anthelmintics. This would help minimize the use of anthelmintics, protect refugia and allow animals to remain healthy by maintaining a balance with the low levels of parasites present.

Bacillus thuringiensis strains with high insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera

Abstract The concept of sustainable agricultural development is aimed at reducing the use of chemical pest control agents. Since the use of chemical pesticides poses a significant environmental threat, one of the possible solutions to overcome this problem is the study of biological approaches, in particular, the use of entomopathogenic microorganisms as biological pest control agents. Insecticidal activity of over 220 strains of Bacillus thuringiensis (Bt) and Lysinibacillus sphaericus from the collection of the Laboratory of Spore-Forming Microorganisms of the Microbial Depository Center of the Scientific and Production Center “Armbiotechnology” and 15 strains isolated from samples of dead insects (imago) of representatives of various genera of the Coleoptera order was studied. The pathogenic effect of the strains was assessed in relation to the insect species Tenebrio molitor, Zophobas morio, Leptinotarsa decemlineata Say and Pieris brassicae, belonging to the Coleoptera and Lepidoptera orders. Among the test objects, the representative of Lepidoptera Pieris brassicae demonstrated the highest degree of sensitivity to B. thuringiensis strains up to 100%, with some Bt strains causing 60–100% mortality of Tenebrio molitor and Zophobas morio larvae of different ages. The larvae of the beetle Leptinotarsa decemlineata Say were also partially susceptible, presenting mortality levels of between 31 and 60%. The article is devoted to the study of Bt bacterial strains that have pronounced insecticidal activity against insect larvae of the orders Coleoptera and Lepidoptera.

Assessing the status of soil seed bank in Parthenium hysterophorus invaded land use types and its social aspects in Lower Hare Watershed, Southern Ethiopia

In Ethiopia, Parthenium hysterophorus (P. hystrophorus) is an invasive alien plant affecting various ecosystems. P. hysterophorus displaced native plant species and caused a serious threat to biodiversity. This study aimed to assess soil seed bank of P. hysterophorus under major land use types and assess community perception towards the effects of P. hysterophorus on social aspects in lower Hare watershed. For this study, 210 soil samples were collected from fifteen transect lines in grassland, cropland, and forest land use types. Statistical analysis using three ways factorial ANOVA was used to analyze the difference in density of P. hysterophorus among various land uses soil depths, and sites (P < 0.05). For the perception of local communities regarding the effects of P. hysterophorus, a total of 117 respondents were used and semi-structured and close-ended questionnaires for data collection. It found that all factors: land use, site, and soil depth significantly affected the soil seed bank density in the lower Hare watershed (P < 0.05). Results indicated that mean density of seeds were the highest in croplands of other land use types. Meanwhile, the highest mean density of seeds was identified in 0-10 cm soil depth, but the lowest mean density of seeds was identified in 10-15 cm soil depth. The highest seeds were identified at Chano Cheliba, but the density of seeds the lowest in density at Kola Shera. 38.5% of households in Kola Shera, and 21.4% in Kola Cheliba, but 8.5% in Kola Doriga said that it had effects on ecosystem services such as crop yield and livestock production. There should be a need for increased awareness about the density of P. hysterophorus in various land uses and its impacts on native plant species. Seeking possible solutions such as biological and mechanical control methods are among the local people, researchers, and extension workers can use for the management of its invasion, and appropriate control measures can be designed to combat its further invasion and impacts on different land uses of the region.

Natural Occurrence of Metarhizium rileyi on Darna diducta as a Biological Control for Oil Palm Pests in Poso, Central Sulawesi

Natural Occurrence of Metarhizium rileyi on Darna diducta as a Biological Control for Oil Palm Pests in Poso, Central Sulawesi

Tomato Root Exudates Infected by Meloidogyne incognita Impact the Colonization of Nematicidal Proteus vulgaris.

Root exudates play a pivotal role in shaping the microbial community in the rhizosphere and can impact the efficacy of bacteria in controlling nematode populations. This study identified Proteus vulgaris BX-1 as significantly effective in controlling Meloidogyne incognita. The infection of tomato plants with this nematode induced noticeable alterations in the composition of tomato root exudates and led to an increased colonization rate of strain BX-1. Further investigation into how strain BX-1 responded to changes in tomato root exudates revealed that specific metabolites, such as caffeic acid, coumarin, salicylic acid, sebacic acid, and butyric acid, strongly attracted strain BX-1. This attraction potentially contributed to its enhanced colonization and improved efficiency in controlling nematodes. Understanding the correlation between specific metabolites in root exudates and the response of antagonistic bacteria provides valuable insights for enhancing their effectiveness as biological control agents against plant-parasitic nematodes.

Unlocking Innovation in Crop Resilience and Productivity: Breakthroughs in Biotechnology and Sustainable Farming

Recent advancements in agricultural biotechnology and sustainable practices are revolutionizing crop production and resilience, addressing global food security challenges. This review highlights cutting-edge innovations in plant sciences, including genetic engineering, genome editing technologies, and biotechnological interventions that enhance crop resistance to biotic and abiotic stresses. It discusses the integration of precision agriculture and digital farming tools that optimize resource use and boost productivity, providing data-driven insights for better crop management. Additionally, sustainable agricultural practices such as agroecology, organic farming, and integrated pest management are examined for their potential to reduce environmental impact while maintaining high yield. The review investigates the key practices like conservation tillage, crop rotation, and biological pest control, emphasizing their roles in enhancing soil health, biodiversity, and agricultural resilience. Significant contributions of biotechnological interventions, including genetic engineering and genome editing, are explored for developing stress-resistant and high-yield crop varieties. Moreover, the integration of precision agriculture and digital farming technologies is discussed for their potential to optimize resource utilization and improve crop management through advanced data analytics.

Isolation, Pathogenicity and Safety Evaluation of Pathogen from Buffalbur (Solanum rostratum) in China

Abstract Buffalobur (Solanum rostratum Dunal) () is an invasive weed in China, identifying its pathogens is crucial for developing effective biological control measures. In this study, leaf samples from S. rostratum showing typical disease symptoms were collected in Liaoning and Jilin provinces, China. The isolated fungal pathogens were identified based on their morphological characteristics and by using molecular biology techniques. Pathogenicity was assessed by artificially inoculating spore suspensions from the fungal pathogen onto the seeds, isolated leaves, and plants of S. rostratum. The safety of the fungal pathogens for eight plant species was also evaluated. We then identified the following five fungal pathogens causing disease in S. rostratum in Liaoning and Jilin provinces: Alternaria alternata, Epicoccum sorghinum, Fusarium equiseti, Curvularia hawaiiensis, and Nigrospora oryzae. These fungal pathogens exhibited pathogenicity, with N. oryzae exhibiting the strongest pathogenicity and highest safety. N. oryzae demonstrated the highest inhibition rate against the radicle germination length of S. rostratum and showed robust pathogenicity towards both isolated leaves and plants. Notably, despite inducing mild reactions in corn, sorghum, rice, and tomatoes, N. oryzae did not impose any detrimental effects on the growth of these plants.

Characterization and pathogenicity of newly recorded Clonostachys rogersoniana against woolly apple aphid (Eriosoma lanigerum Hausmann) from India

BackgroundWoolly apple aphid (Eriosoma lanigerum Hausmann) (Homoptera: Aphididae) infests the aerial and edaphic portions of apple trees. It is responsible for the serious qualitative and quantitative reduction in apple fruits. This pest is mainly managed by chemical insecticides, so this present study was focused on the isolation of native entomopathogenic fungi (EPF), studying their growth characteristics and virulence against woolly apple aphids.ResultsClonostachys rogersoniana, as an EPF from an insect cadaver, was isolated and characterized, using morphological, microscopic, and molecular techniques. To the best of our knowledge, this is the first report of the occurrence of this fungus from India and it is named “C. rogersoniana isolate PUSACR01”. The radial growth and conidial yield of this isolate were excellent on PDAY among ten different culture media, whereas the relative growth rate and conidial germination were good on PDA and CA. The isolated fungus showed 85 and 86.67% mortality rates in adult females of the woolly apple aphid on day 11 at a concentration of 1.0 × 107 and 1.0 × 108 conidia ml−1, respectively. The LC50 values determined by probit regression analysis for days 7, 9, and 11 were 1.12 × 107, 2.52 × 106, and 4.74 × 105 conidia ml−1, respectively, while LT50 for concentrations of 1.0 × 105, 1.0 × 106, 1.0 × 107, and 1.0 × 108 conidia ml−1 were 18.73, 9.39, 6.71, and 5.03 days, respectively.ConclusionBased on the present study, C. rogersoniana would be considered a good biological control agent against the woolly apple aphid in apple orchards.

Evaluation of a Novel Streptomyces avermitilis Strain from Egyptian Soil for Biological Control of Tetranychus urticae in Greenhouse Cucumber Plantations

Background: Infestation in greenhouse cucumber with the two-spotted spider mite (Tetranychus urticae Koch) commonly causes severe damage to crop quality and quantity and increases crop production costs. Objective: This study was conducted to investigate the efficacy of high-abamectinproducing isolates of S. avermitilis against T. urticae-infested cucumber and to assess their impact on biochemical stress markers in these vegetables. Methods: In this study, 72 non-antagonistic Streptomyces were isolated from rhizospheric soil samples collected from eight different locations in Egypt and screened for their ability to produce the secondary metabolite, abamectin Results: The screening process identified two potent abamectin-producing isolates, EW8 and T2, which produced 42.7 and 29.6 μg/L abamectin, respectively, as confirmed by LC-MS/MS analysis. According to DNA sequence analysis of the 16S rRNA gene, these two isolates belong to the species S. avermitilis. The acaricidal activity of either culture suspensions of S. avermitilis strains WE8 and T2, or their extracts containing abamectin, against the mobile stages and egg hatchability of T. urticae was evaluated in the laboratory and the greenhouse. Data on the mortality among the examined female mites and the reduction in their number of eggs point out a potential acaricidal activity of the examined strains of S. avermitilis and their extracts containing abamectin against T. urticaes. Furthermore, the extracts containing abamectin from these two S. avermitilis strains induced oxidative stress in the infested cucumber plants by T. urticaes, as indicated by increased levels of malondialdehyde (MDA). However, the levels of MDA in T. urticae-infested cucumber plants varied depending on the strain and the specific abamectin crude extract used. Conclusion: S. avermitilis strains T2 or WE8, or their crude extract could be applied in greenhouse cucumber plantations to combat red mite infestation (Fig. 1).

Side effects of insecticides used for management of Tuta absoluta Meyrick (Lepidoptera: Gelechidae) on the biocontrol agent Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae)

Trichogramma brassicae is one of the most important egg parasitoids of many pests including South American tomato pinworm, Tuta absoluta (Lepidoptera: Gelechiidae). In agrosystems, the function of parasitoids can be affected by the application of insecticides. To use biological control agents and pesticides simultaneously in pest management, it is necessary to know the potential effect of pesticides on biological control agents. In this study, the lethal and sublethal effects of four insecticides (flubendiamide, emamectin benzoate + lufenuron, thiocyclam, and spinosad) frequently used to control T. absoluta, were investigated on its parasitoid Trichogramma Brassicae Bezdenko (Hymenoptera: Trichogrammatidae), under controlled laboratory conditions. The results showed that spinosad with an LC50 value of 0.73 mg a.i./ L was highly toxic against adults of T. brassicae in comparison to flubendiamide (4.09 mg a.i./ L), emamectin benzoate + lufenuron (4.17 mg a.i./ L), and thiocyclam (9.59 mg a.i./ L). Furthermore, key demographic parameters such as net reproductive rate (R0), intrinsic rate of increase (rm), mean generation time (T), and doubling time (DT) were significantly decreased after exposure of T. brassicae to the LC30s of spinosad, thiocyclam, flubendiamide, and emamectin benzoate + lufenuron compared to the control. In the light of our results, the four insecticides should be used cautiously in T. absoluta integrated management programs. While the thiocyclam can be combined with the T. brassicae, the flubendiamide and emamectin benzoate + lufenuron are not recommended in the presence of this parasitoid. The use of spinosad should be avoided concomitantly with the release of T. brassicae.