International Organization For Biological Control Research Articles

Deconstructing the IOBC tiered method: Are we overestimating the compatibility of pesticides and natural enemies?

Accurately estimating the risk of sensitive populations subjected to toxicant disturbances is central to our ability to protect ecosystem services. While the gold standard for assessing risk historically involves static measures such as the LD50 or LC50, more sophisticated approaches have been developed in an attempt to capture more nuanced outcomes. In the 1980s the International Organization for Biological Control (IOBC) developed a tiered approach to determine the compatibility of pesticides and natural enemies in the context of integrated pest management (IPM). We analyzed the IOBC approach using stage-based matrix models to project population outcomes for four parasitoid species, Diaeretiella rapae, McIntosh, Fopius arisanus, (Sonan), Diachasmimorpha longicaudata Ashmead, Psyttalia fletcheri (Silvestri) and the predator, Coccinella septempunctata L. By imposing mortality levels in matrix models equivalent to those outlined in the IOBC Tier 1 Class 1 (29 %) (harmless) and Class 2 (79 %) (slightly harmful) mortality classes, we explored discrepancies between the IOBC approach and population outcomes generated by these models. Our results highlight that the IOBC Class 1 and 2 levels of mortality are too high to protect many natural enemies from pesticides, setting the stage for unrealistically optimistic views of pesticide compatibility in many cases. Furthermore, a one size fits all approach to protect natural enemies from pesticides does not work because of differences in demographic rates among species which will be less negatively affected by Tier 1 levels of mortality and those that do not reproduce quickly and will thus be more vulnerable to pesticides. Therefore, the IOBC method should be used cautiously if at all, and results should be interpreted with the caveats and pitfalls highlighted here. Results of this study indicate that it is time to reevaluate how we estimate pesticide compatibility with natural enemies and adjust the methods and mortality thresholds based on more realistic measures of toxicity.

Acute toxicity effects of pesticides on beneficial organisms – Dispelling myths for a more sustainable use of chemicals in agricultural environments

Agricultural practitioners, researchers and policymakers are increasingly advocating for integrated pest management (IPM) to reduce pesticide use while preserving crop productivity and profitability. Using selective pesticides, putatively designed to act on pests while minimising impacts on off-target organisms, is one such option – yet evidence of whether these chemicals control pests without adversely affecting natural enemies and other beneficial species (henceforth beneficials) remains scarce. At present, the selection of pesticides compatible with IPM often considers a single (or a limited number of) widely distributed beneficial species, without considering undesired effects on co-occurring beneficials. In this study, we conducted standardised laboratory bioassays to assess the acute toxicity effects of 20 chemicals on 15 beneficial species at multiple exposure timepoints, with the specific aims to: (1) identify common and diverging patterns in acute toxicity responses of tested beneficials; (2) determine if the effect of pesticides on beetles, wasps and mites is consistent across species within these groups; and (3) assess the impact of mortality assessment timepoints on International Organisation for Biological Control (IOBC) toxicity classifications. Our work demonstrates that in most cases, chemical toxicities cannot be generalised across a range of beneficial insects and mites providing biological control, a finding that was found even when comparing impacts among closely related species of beetles, wasps and mites. Additionally, we show that toxicity impacts increase with exposure length, pointing to limitations of IOBC protocols. This work challenges the notion that chemical toxicities can be adequately tested on a limited number of ‘representative’ species; instead, it highlights the need for careful consideration and testing on a range of regionally and seasonally relevant beneficial species.

Compatibility of pesticides with the predatory mite Neoseiulus barkeri.

Multiple arthropod pests can affect the same crop in agricultural systems, requiring the integration of control methods. In the present study, the effects of residual exposure to four broad-spectrum insecticides/acaricides (azadiractin, abamectin, chlorfenapyr, and fenpyroximate) on immature (development and survival time) and adult females (longevity, fecundity, and fertility life table parameters) of the predatory mite Neoseiulus barkeri were evaluated. Additionally, the insecticides/acaricides were categorized according to their selectivity based on the classification proposed by the International Organization for Biological Control (IOBC) for assessing the susceptibility of arthropods in laboratory experiments. Method 004, proposed by the Insecticide Resistance Action Committee (IRAC), was adopted for the bioassays with predators exposed to insecticide-acaricide residues. Among the insecticides/acaricides studied, azadirachtin had minimal effects on immature and adult N. barkeri (all non-significant) and was considered harmless based on the classification of toxicity according to the standards/categories proposed by the IOBC. All other insecticides/acaricides affected immature and adult N. barkeri and were considered slightly harmful in terms of toxicity, according to the IOBC.

Selectivity of acaricides to Neoseiulus barkeri (Hughes) (Acari: Phytoseiidae)

AbstractNeoseiulus barkeri Hughes has been used to control several pests, including the red palm mite, Raoiella indica Hirst. However, in some situations, the exclusive use of biocontrol agents is not sufficient to prevent the damage caused by pests. In these scenarios, the integration of chemical and biological controls is desired. For that purpose, the determination of selective acaricides, avoiding or reducing deleterious effects on the biological control agent is desirable. This study evaluated the lethal and sublethal effects of acaricides (abamectin, azadirachtin, fenpyroximate and pyridaben) on the predatory mite N. barkeri. We investigated the toxicity and selectivity of the acaricides and the survival, fertility, egg viability and instantaneous growth rate (ri) of N. barkeri exposed to acaricides. Additionally, we classified the acaricides according to the scale proposed by the International Organization for Biological Control (IOBC). Among the acaricides evaluated, abamectin was selective for N. barkeri because the estimated lethal concentration (LC50) for N. barkeri was higher than that for R. indica. None of the acaricides affected predator survival curves. However, azadirachtin and fenpyroximate reduced the average predator survival time. Pyridaben was the only acaricide that reduced the fertility of N. barkeri females and, consequently, their instantaneous growth rate (ri). All the acaricides affected the viability of N. barkeri eggs. Pyridaben was classified as moderately harmful, whereas other acaricides were classified as harmless.

TOXICITY OF Argemone mexicana (L.) EXTRACTS AND IMIDACLOPRID ON Chrysoperla carnea (Stephens)

In sorghum (Sorghum bicolor L. Moench) cultivation, the main pest is the sugarcane aphid (Melanaphis sacchari Zehntner (Hemiptera: Aphididae)). The insecticide imidacloprid is frequently used to control this insect, and in some cases, it is complemented with the release of lacewings of the species Chrysoperla carnea Stephens (Neuroptera: Chrysopidae). The insecticide has been shown to be harmful to non-target insects, such as the natural enemies of this aphid, so it is necessary to find other less harmful products. The objective of this study was to evaluate the toxicity of aqueous and oily extracts of chicalote (Argemone mexicana L.) on C. carnea and to contrast it with that of imidacloprid, with the hypothesis that extracts of A. mexicana applied to the developmental stages of C. carnea generate less mortality on the predator than imidacloprid. The aqueous and oily extracts had a concentration of 30 g L-1. For imidacloprid, the recommended dose for sugarcane aphid control (0.35 g L-1) was used. Mortality and the treatments effect were evaluated by exposure methods: T1) topical on larvae, T2) egg immersion, T3) treated Sitotroga cerealella eggs, and T4) liquid ingestion in adults. Mortality, hatching and emergence variables were analyzed with a one-way ANOVA, followed by Tukey’s comparison of means (p ≤ 0.05). Treatments were classified according to the toxicity levels proposed by the International Organization for Biological Control. The aqueous and oily extracts were in toxicity class 1 for C. carnea, except in eggs treated with the oily extract (class 4). Imidacloprid was classified in class 4 when applied topically and by ingestion in adults and in class 2 in ingestion of treated S. cerealella eggs. In general, extracts of A. mexicana could be used as selective insecticides, while imidacloprid can be considered incompatible with releases of this predator.

Effect of entomopathogenic fungus-formulated bioinsecticides on stingless bees (Hymenoptera: Apidae: Meliponini) in the laboratory

Stingless bees are of environmental and economic importance because they pollinate plants of agricultural and native interest. During foraging, bees can come into contact with synthetic insecticides, resulting in lethal and sublethal effects. Biological control using entomopathogenic fungi (EF) is an alternative to the use of synthetic insecticides. However, despite promising results in pest control, gaps in the activity of EF on nontarget organisms, such as stingless bees, have not been completely recognized. Thus, this work aimed to evaluate the effects of three bioinsecticides formulated from Beauveria bassiana (Boveril®WP), Metarhizium anisopliae (Metarril®WP), and Cordyceps fumosorosea (Octane®SC) on Melipona quadrifasciata, Plebeia droryana, and Scaptotrigona bipunctata (Hymenoptera: Apidae). Direct contact with the concentration of 107 conidia.mL−1 indicated a differentiated tolerance between bee species, as well as significant differences in mortality caused by these bioinsecticides. Melipona quadrifasciata showed the lowest tolerance to bioinsecticides, while S. bipunctata had the lowest mortality. According to the classification proposed by the International Organization for Biological Control, the Boveril®WP and Metarril®WP bioinsecticides were characterized as harmless to moderately harmful. Octane®SC caused mortality between 74.7 and 95% and was thus characterized as harmful to all three studied species. Although these bioinsecticides are selective for nontarget organisms, it is evident that the toxicity for stingless bees is dependent on the EF species used. Thus, its use must be carried out according to criteria that minimize damage to bees, effectively resulting in the development of sustainable agriculture.

Evaluation of Lethal and Sublethal Effects of Methyl Benzoate on the Generalist Predator Orius laevigatus (Fieber).

Methyl benzoate (MBe), a volatile organic molecule, has been shown to have insecticidal effects on a variety of agricultural, stored products, and urban arthropod pests in recent investigations. However, the toxicity of MBe against nontarget organisms has rarely been investigated. This study investigated the lethal and sublethal effects of MBe on the generalist predator Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) via different exposure routes. This species is an important natural enemy of thrips, aphids, and mites in biological control programs globally. Acute toxicity bioassays conducted on O. laevigatus showed that the lethal median concentration (LC50) values of MBe for topical and residual toxicity were 0.73 and 0.94%, respectively, after 24 hr of exposure. Importantly, a sublethal concentration of MBe (LC30 = 0.51%) did not affect the survival and reproduction of O. laevigatus. In addition, prey consumption by O. laevigatus under different exposure conditions with varying densities of Aphis gossypii (Glover) (Hemiptera: Aphididae) adults demonstrated a good fit for a Type II functional response. The sublethal concentration of MBe did not affect the attack rate and handling time of O. laevigatus compared to untreated insects, nor did it affect the longevity and fecundity of O. laevigatus females. Thus, according to the International Organization for Biological Control, the sublethal MBe concentration for O. laevigatus is categorized as harmless and may be used in conjunction with this predator species for integrated control of many agricultural insect pests.

Efficacy of Four In Vitro Fungicides for Control of Wilting of Strawberry Crops in Puebla-Mexico

Strawberry wilt is an established disease of strawberry crops caused by fungus Fusarium solani. In Mexico, strawberry cultivation represents an important productive activity for several rural areas; however, wilt disease affects producers economically. The objectives of this research were: (a) to identify and morphologically characterize strain “MA-FC120” associated with root rot and wilting of strawberry crops in Santa Cruz Analco, municipality of San Salvador el Verde, Puebla-Mexico; (b) to evaluate the potential of single and multiple applications of four broad-spectrum fungicides used against F. solani in vitro. Plant tissue samples were collected from strawberry crops in Puebla-Mexico with presence of symptoms of desiccation and root rot. Strain “MA-FC120” was identified as F. solani, being the causal agent of wilt and root rot in strawberry plants from Santa Cruz Analco. Fungicide Benomyl 50® showed the highest percentage of inhibition on F. solani (100%) under in vitro conditions. The fungicide Mancosol 80® and Talonil 75® at low concentration (600 and 450 mg L−1) showed no toxicity, being harmless to strain MA-FC120. However, fungicide Talonil 75® showed slight toxicity at the dose recommended by the manufacturer and moderate toxicity in high concentration (1350 mg L−1). Likewise, Captan 50® in its three concentrations evaluated showed slight toxicity, obtaining around 50% on the classification scale established by International Organization for Biological Control (IOBC).

Insect Invasive Species: Threat Posed and Collaborative Efforts for Management

Insects are a highly diverse group of organisms and their rich diversity is essential for ecosystem functioning. Insects have more influence on agriculture and most agricultural pests are invasive species that have been introduced into a new ecosystem. These invasive species have the capacity to compete, establish and displace the native species and therefore can be a threat to biodiversity. Introduction of such invasive species has increased with the increase in trade across the globe. Therefore, it is pertinent to strengthen the International cooperation and coordination between the affected countries and the country of native origin to identify the threat for the execution of different mitigation strategies. International Organization for Biological Control (IOBC), Centre for Agriculture and Bioscience International (CABI) and the Biotechnology and Biological Control Agency facilitate international collaboration and play a vital role in managing invasions by alien pests. In India, Directorate of Plant Protection, Quarantine and Storage (DPPQ&S), ICAR-NBPGR, ICAR-NBAIR and other crop-specific institutes of ICAR, Ministry of Agriculture and Farmers’ Welfare, Government of India are the bodies engaged in monitoring of invasive insects/invasive alien species. Thus, international collaboration plays a key role in research on the prevention of future invasions, the development of more effective surveillance and eradication methods and the implementation of classical biological control.

Toxic effects of some acaricides on Aceria oleae (Nalepa, 1900) (Acari: Eriophyidae) and its predator Neoseiulus californicus (McGregor, 1954) (Acari: Phytoseiidae) under laboratory conditions

Olive bud mite, Aceria oleae (Nalepa, 1900) (Acari: Eriophyidae) is one of the key pests that regularly needs control with acaricides in olive orchards of Bursa Province, Turkey. For the chemical control of A. oleae , it is critical the use of acaricides does not reduce the survival and fecundity of its natural enemies. The toxic effects of three concentrations of seven acaricides were assessed against both A. oleae and its predator Neoseiulus californicus (McGregor, 1954) (Acari: Phytoseiidae) using a residual method under controlled conditions at Bursa Uludağ University during 2020-2021. The highest recommended concentrations of acequinocyl, azadirachtin, fenbutatin oxide, milbemectin, pyridaben, spirodiclofen and sulfur killed A. oleae adults with rates varying from 80 to 100%. Two concentrations of milbemectin, pyridaben and sulfur showed high mortality rates. Nevertheless, highest recommended concentrations of acequinocyl, pyridaben, spirodiclofen and sulfur were found to be highly toxic to N. californicus adults with rates varied from 82 to 100%. The high mortalities for mobile immature stages and reducing in the fecundity of N. californicus occurred by highest recommended concentrations of all tested acaricides. Based on the scale recommended by the International Organization for Biological Control, some sublethal concentrations of fenbutatin oxide, spirodiclofen and sulfur were found to be slightly harmful to both mature and immature of N. californicus .

Residual toxicity of selected insecticides on Aphis gossypii and their safety limits on honeybees

AbstractEvaluation studies were carried out to simulate realistic field exposures of sulfoxaflor and flonicamid againstAphis gossypiiat foraging time ofApis mellifera. Semi-field trials of field rates of sulfoxaflor and flonicamid againstA. gossypiilaboratory strain at 48 h of exposure had equipollent overall mean of mortality of 62.50 and 63.50%, respectively in season of 2020, likewise 60.50 and 62.50%, respectively in season of 2021. Lethal time values (LT1) had ranges of 51.33–32.46 days for sulfoxaflor and 49.00–39.55 days for flonicamid. Laboratory trials on foraging honeybees (∼21 days old) at 5 h of exposure showed an excellence for sulfoxaflor (5.00%) in overall mean of mortality compared to flonicamid (2.75%) in season of 2020. Likewise, sulfoxaflor (4.75%) surpassed flonicamid (2.75%) in season of 2021. The highest LT1s on honeybees for sulfoxaflor and flonicamid reached 27.45 and 10.94 days, respectively. International Organization for Biological Control classified both insecticides to be harmless on honeybees. Survival foraging bees exposed to LD50s of the tested insecticides had malformed digestive tracts gradually vanished along week of exposure. Suggestions for foliar spray stoppages prior to flowering period were mentioned for both insecticides.

Assessment of Toxicity Risk of Selected Insecticides Used in Pistachio Ecosystem on Two Egg Parasitoids (Hymenoptera: Scelionidae) of Stink Bugs (Hemiptera: Pentatomidae).

Psix saccharicola (Mani) and Trissolcus semistriatus (Nees) are the most abundant eggs parasitoids of the stink bug, Acrosternum arabicum Wagner, in pistachio orchards and have the potential to contribute to their suppression. However, treatment of orchards with broad-spectrum insecticides may greatly reduce populations of these beneficial natural enemies. Therefore, we conducted risk assessments and evaluated sublethal impacts of two insecticides routinely used in pistachio orchards: the organophosphate fenitrothion and a formulated mixture of the neonicotinoid thiamethoxam and the pyrethroid lambda-cyhalothrin on parasitism success, emergence and sex ratio of P. saccharicola and T. semistriatus. Based on the values of their risk quotients (RQ), which are derived from toxicity data, the two insecticide products would be classified as slightly-to-moderately toxic although an alternative metric, the safety factor (SF), showed them to be highly risky. Assessments of sublethal effects on adult wasps showed that insecticide exposure significantly reduced their ability to successfully parasitize stink bug eggs, and exposure of adult females reduced the emergence, survival, and proportion of females of their progeny, which could disrupt biological control for an extended period of time. Analysis of the decreased emergence and parasitism for P. saccharicola and T. semistriatus in accordance with the standards of the International Organization for Biological Control (IOBC) indicate that fenitrothion is slightly harmful to both parasitoid species whereas the mixture of thiamethoxam + lambda-cyhalothrin is moderately harmful. These findings will be useful for integrating insecticides and egg parasitoids into a comprehensive integrated pest management program for managing stink bugs populations in pistachio orchards.

Commemoration of Dr. Barnabás Nagy, a Research Entomologist on a Mission to Serve Biodiversity and Agrozoology

Dr. Barnabás Nagy(1921–2020), a naturalist, orthopterologist, agrozoologist and forward-looking ecologist covered a rich scientific career. In commemoration of his significant contribution to entomology, we attempt to shed some light on a selection of his achievements. While devoted to his chosen insect order, Orthoptera, he was sensitive also to problems coming from everyday’s practice in controlling pests in agriculture. Consequently, he dealt with various pest species, belonging to a variety of insect taxa (Coleoptera, Lepidoptera, Hymenoptera). He always put the actual problem in ecological context. This may have helped him to recognize the need for an ecological approach in plant protection and to develop the pioneering concept of biological / ecological pest management, published in Hungarian, as early as in 1957. When arguing for his concept, he criticized the surplus usages of toxic pesticides and provided guidelines for facilitating the beneficial activity of the natural enemies of pests. This way he prepared the way for integrated pest management (IPM), preceding the international mainstream of his age. He held an active part in the International Organization for Biological Control (IOBC), as a founder of the International Working Group of Ostrinia (IWGO), and was the Head of the Department of Zoology of the Plant Protection Institute, Budapest, Hungary. He held several positions in the Hungarian Entomological Society (President, vice-President, Secretary, committee member), to that society he was engaged for 80 years. Here we cite only some of his most important, original entomological papers. He regularly published also in journals for popular science and gave lectures for the young generations of entomologists.Curriculum vitae in a nutshell

Toxicity of Insecticides and Miticides to Natural Enemies in Australian Grains: A Review.

Simple SummaryControlling invertebrate pests in crop fields using chemicals has been the main management strategy within the Australian grains industry for decades. However, chemical use can have unintended effects on natural enemies, which can play a key role in suppressing and controlling pest outbreaks within crops. We undertook a literature review of studies that have conducted chemical toxicity testing against arthropod natural enemies relevant to the Australian grains industry to examine trends and highlight research gaps and priorities. Most toxicity trials have been conducted in the laboratory, with few at larger, and hence, industry-relevant scales. Researchers have used a variety of methods when conducting toxicity testing, making it difficult to compare within and across different species of natural enemies. Furthermore, we found many gaps in testing, leading to unknown toxicity effects for several key natural enemies, some of which are economically important predators and parasitoids. Through our review, we make several key recommendations for future areas of research that could arm farmers and their advisors with the knowledge they need to make informed decisions when it comes to controlling crop pests.Continued prophylactic chemical control to reduce pest populations in Australian grain farming systems has limited the effectiveness of biological control via natural enemies in crops within an integrated pest management (IPM) framework. While a variety of data is available to infer potential non-target effects of chemicals on arthropod natural enemies, much of it may be irrelevant or difficult to access. Here, we synthesise the literature relevant to Australian grain crops and highlight current knowledge gaps for potential future investment. A range of testing methodologies have been utilised, often deviating from standardised International Organization for Biological Control (IOBC) protocols. Consistent with findings from over 30 years ago, research has continued to occur predominantly at laboratory scales and on natural enemy families that are easily reared or commercially available. There is a paucity of data for many generalist predators, in particular for spiders, hoverflies, and rove and carabid beetles. Furthermore, very few studies have tested the effects of seed treatments on natural enemies, presenting a significant gap given the widespread global use of neonicotinoid seed treatments. There is a need to validate results obtained under laboratory conditions at industry-relevant scales and also prioritise testing on several key natural enemy species we have identified, which should assist with the adoption of IPM practices and decrease the reliance on broad-spectrum chemicals.

Selectivity of mycoinsecticides and a pyrethroid to the egg parasitoid Cleruchoides noackae (Hymenoptera: Mymaridae)

Plants of the genus Eucalyptus, cultivated in many countries, have great importance for the world economy. In Brazil, this culture occupies a total of 5.7 million hectares, but native and exotic insect pests can reduce its productivity. Thaumastocoris peregrinus Carpintero & Dellapé (Hemiptera: Thaumastocoridae), an exotic Australian pest, damages Eucalyptus plants. Biological control using the egg parasitoid Cleruchoides noackae Lin & Huber (Hymenoptera: Mymaridae), Heteroptera predators and entomopathogenic fungi, such as Beauveria bassiana and Metarhizium anisopliae, have potential for managing T. peregrinus. Chemical insecticides, including bifenthrin and acetamiprid + bifenthrin, also control this insect. The compatibility of chemical and biological control methods favors integrated pest management. The objective of this study was to evaluate the selectivity of commercial products based on B. bassiana, M. anisopliae and the chemical bifenthrin on the parasitoid C. noackae and its parasitism on T. peregrinus eggs. The selectivity test followed the standards recommended by the International Organization for Biological Control (IOBC). Beauveria bassiana has selectivity to parasitism as well as viability, but was slightly harmful to C. noackae adults; M. anisopliae was innocuous to adults and to the viability of the offspring of this parasitoid, but it reduced the parasitism rate; and bifenthrin did not show selectivity to this parasitoid.

Insecticide susceptibilities of Hydrometra species (Hemiptera: Hydrometridae), including an endangered species, inhabiting paddy fields in Japan

Freshwater ecosystems tend to have the highest proportion of species threatened with extinction. Paddy fields provide alternative habitats for many species inhabiting wet hinterlands of rivers. This study examined the susceptibilities of three hydrometrid species, Hydrometra procera Horvath (Hemiptera: Hydrometridae), H. albolineata (Scott) (Hemiptera: Hydrometridae), and H. okinawana Drake (Hemiptera: Hydrometridae), inhabiting paddy fields in Japan to seven insecticides that were frequently applied to paddy fields, and evaluated the effect of each insecticide according to the hazard assessment classes by the International Organization for Biological Control and Integrated Control of Noxious Animals and Plants/West Palearctic Regional Section. Etofenprox, imidacloprid, and fenobucarb were found to be seriously harmful to the third instar nymphs of the three hydrometrid species. Buprofezin (an insect growth regulator) was also evaluated as seriously harmful based on the mortality at the third instar of the three species before the completion of molting to the fourth instar. Etofenprox, imidacloprid, and buprofezin were particularly harmful even at low concentrations to H. procera. Some of these insecticides have been heavily used in paddy fields since the 1950s or 1960s. It was around this time when the endangered species, H. albolineata populations began to decline drastically. Our results suggested that heavy use of these insecticides is one of the factors that caused the decline in H. albolineata populations.

Selectivity and sublethal effect of botanical extracts on adults of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

The objective was to assess the selectivity and sublethal effect of botanical extracts on adults of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae). Plant species used: Rosmarinus officinalis L., Mikania glomerata Spreng., Varronia curassavica Jacq., Chenopodium ambrosioides L., Vermonia polyanthes Spreng., Plectranthus amboinicus Spreng., Tetradenia riparia Codd., Artemisia absinthium L., Cymbopogon citratus Stapf. Plant material were reared in laboratory and leaves collected during the morning were used to prepare the extracts as following: 100 g of leaves from each plant were macerated and immersed in 300 mL of triple-extracted methyl alcohol and evaporated on rotavapor. Then, 250 mg of crude extract was diluted in 1000 mL of water. The experimental design for selectivity was done in randomized blocks with five repetitions, following a standardized protocol of the International Organization for Biological Control (IOBC) and accordingly classified. In sublethal effect, the design was completely randomized with twenty repetitions, where the eggs exposed to parasitism were sprayed with the treatments. In both experiments the control was twofold (water and chlorpyrifos). Regarding selectivity, the botanical extracts of M. glomerata, C. ambrosioides, V. polyanthes, P. amboinicus, A. absinthium and C. citratus were classified as slightly harmful (class 2), chlorpyrifos as moderately harmful (class 3). In the evaluation of sublethal effects, the botanical extracts of C. ambrosioides and C. citratus initially presented reduced number of parasitized eggs, reduction in total parasitized eggs and female longevity. It can be concluded that C. citratus botanical extract has small selectivity and causes sublethal effects on T. pretiosum adults.

Selectivity and sublethal effect of botanical extracts on adults of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)

The objective was to assess the selectivity and sublethal effect of botanical extracts on adults of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae). Plant species used: Rosmarinus officinalis L., Mikania glomerata Spreng., Varronia curassavica Jacq., Chenopodium ambrosioides L., Vermonia polyanthes Spreng., Plectranthus amboinicus Spreng., Tetradenia riparia Codd., Artemisia absinthium L., Cymbopogon citratus Stapf. Plant material were reared in laboratory and leaves collected during the morning were used to prepare the extracts as following: 100 g of leaves from each plant were macerated and immersed in 300 mL of triple-extracted methyl alcohol and evaporated on rotavapor. Then, 250 mg of crude extract was diluted in 1000 mL of water. The experimental design for selectivity was done in randomized blocks with five repetitions, following a standardized protocol of the International Organization for Biological Control (IOBC) and accordingly classified. In sublethal effect, the design was completely randomized with twenty repetitions, where the eggs exposed to parasitism were sprayed with the treatments. In both experiments the control was twofold (water and chlorpyrifos). Regarding selectivity, the botanical extracts of M. glomerata, C. ambrosioides, V. polyanthes, P. amboinicus, A. absinthium and C. citratus were classified as slightly harmful (class 2), chlorpyrifos as moderately harmful (class 3). In the evaluation of sublethal effects, the botanical extracts of C. ambrosioides and C. citratus initially presented reduced number of parasitized eggs, reduction in total parasitized eggs and female longevity. It can be concluded that C. citratus botanical extract has small selectivity and causes sublethal effects on T. pretiosum adults.

Combined thermal and insecticidal stresses on the generalist predator Macrolophus pygmaeus

Ecotoxicological risk assessments of pesticides on non-target arthropods are often carried out under constant and optimal temperature regimes. However, living organisms rarely experience these conditions in real field situations. Understanding the impact of pesticides on non-target beneficial arthropods under temperature stresses is especially important in terms of global warming. We assessed the lethal and sublethal effects of four modern insecticides (chlorantraniliprole, cyantraniliprole, spinetoram, spinosad), on the generalist predator Macrolophus pygmaeus (Hemiptera: Miridae) under a range of temperatures (from 10 to 40°C) frequently experienced in a real field scenario. A reduction coefficient (Ex) was calculated by summarizing the mortality and predator reproductive capacity and, the chemicals were classified according to the International Organization for Biological Control (IOBC) toxicity classes. The insecticides showed a marked synergistic effect with temperature, as the predator mortality and reproductive outputs were significantly correlated with increasing temperatures. Spinosyns interacted significantly with temperature causing the highest mortality and lowest fertility rates. Anthranilic diamides showed a safer ecotoxicological profile compared to spinosyns, with cyantraniliprole being more harmful than chlorantraniliprole. These results suggest that temperature should be taken into account in pesticide ecotoxicology studies within the framework of integrated pest management and the recent climate changes.

Selectivity of registered pesticides for the corn crop on immature stages of Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)

ABSTRACT Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) is an egg parasitoid of lepidopteran pests in corn, Zea mays L. (Poaceae), in Brazil. Chemical products used in agriculture can be toxic to this biocontrol agent. The objective of the present study was to evaluate the longevity, parasitism and emergence of T. pretiosum parasitizing Mediterranean flour moth, Anagasta kuehniella Zeller, 1879 (Lepidoptera: Pyralidae), eggs treated with herbicide solutions with the active ingredients (chemical group) atrazine (triazines), paraquat dichloride (bipyridylium) and nicosulfuron (sulfonylurea). Pure distilled water was used as a negative control, and a solution of a product with λ-cyhalothrin + thiamethoxam (pyrethroid + neonicotinoid, respectively) was used as the positive control. The experimental design was completely randomized, with five treatments and 10 replicates. Anagasta kuehniella eggs were stored for two periods after treatment, 24 and 48 hours. These eggs were subjected to parasitism for two subjecting periods, 24 and 48 hours. The results were analysed statistically and classified according to the International Organization for Biological Control (IOBC). Atrazine and nicosulfuron reduced the longevity of T. pretiosum females. Nicosulfuron and the combination λ-cyhalothrin + thiamethoxam reduced the parasitism and emergence of this natural enemy. The paraquat dichloride-based herbicide was the least toxic and therefore represents a potential option for controlling weeds with low toxicity to the T. pretiosum parasitoid.