Search

Integrated pest management (IPM) uses a range of control strategies to diminish pest populations. Hence, the simultaneous utilisation of synthetic insecticides and biological control agents is desirable, although hindered by the possible impact of insecticides on non-target organisms. Plutella xylostella (L.) is a common target of several pesticides in Brassica crops. However, it can also be parasitised by Tetrastichus howardi (Olliff). This study examined the susceptibility of T. howardi to dry residue of cyantraniliprole and spinetoram on inert surfaces and treated kale (Brassica oleracea var. manteiga) leaf discs at field rates (FRs = 10 g a.i. ha−1 and 25 g a.i. ha−1, respectively), 50% of the FR, and at various time intervals (ranging from 2 h to 8 days after application). Survival of T. howardi remained unaffected by cyantraniliprole and spinetoram, regardless of the pesticide rate or spraying interval. Furthermore, the presence of cyantraniliprole and spinetoram in dry residue, when kale leaves were consumed by second-instar P. xylostella larvae at LC25 and LC50 levels, did not have any detrimental impact on the survival of the parasitoids. Similarly, the exposure of T. howardi to contaminated P. xylostella larvae did not have any impact on its ability to parasitise or on the emergence of the parasitoid. Given the minimal effect of cyantraniliprole and spinetoram on T. howardi, these control strategies appear to be suitable for incorporation into an integrated approach for the management of P. xylostella in Brassica crops. [ABSTRACT FROM AUTHOR]

BACKGROUND: Compatibility studies of insecticides and natural enemies usually focus on short‐term lethal effects, without considering the long‐term sublethal effects (including progeny). Even less‐explored are the effects of commercial insecticides formulated with more than one active product. Short‐ and long‐term lethal and sublethal effects were studied for the first time on the progeny of commercial formulations of spirotetramat, imidacloprid and a commercial mixture of these active ingredients on pupae of Diaeretiella rapae (M'ntosh) (Hymenoptera: Braconidae), an endoparasitoid of aphids considered to be a potential biological control agent. Insecticides were exposed topically on aphid mummies in which the parasitoid was in the pupal stage. RESULTS: Imidacloprid reduced adult emergence by more than 30% and prolonged intra‐host development time with respect to control from half the maximum recommended field dose (MFRD). Spirotetramat and commercial mixture only showed significant effects on these endpoints at doses above the MFRD. The tested formulations did not affect adult longevity, sex ratio, and percentage of parasitism in the exposed generation. At low concentrations the active ingredients in the commercial mixture behave synergistically, whereas at medium and high concentrations they behave antagonistically. Considering the 10% lethal dose (LD10), imidacloprid showed the highest hazard coefficient, whereas the commercial mixture was more hazardous when considering the LD50 and LD90. The commercial mixture and imidacloprid induced higher adult emergence and altered the sex ratio in the progeny. CONCLUSIONS: The following order of toxicity on D. rapae can be established: imidacloprid > commercial mixture > spirotetramat. Joint use of this species with imidacloprid and commercial mixture should be avoided in integrated pest management programs. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Simple Summary: Botanical insecticides and soaps are frequently considered environmentally friendly and compatible with the biological control of pests because of their purported higher selectivity towards beneficial insects when compared with synthetic insecticides. These claims are, however, only partially backed up by the scientific literature, thus justifying a case-by-case evaluation of botanical insecticides. Here, we tested the efficacy of five botanical insecticides and soaps belonging to different categories (pyrethrins, essential oils, crude plant extracts and insecticidal soaps) on the important aphid pest Myzus persicae (Sulzer) and their selectivity towards two of its biological control agents, the ladybird beetle Propylea quatuordecimpunctata (L.) and the parasitoid Aphidius colemani (Dalman). The pyrethrin-based product was the most effective against aphids but more detrimental to ladybird beetle larvae when compared to the alternatives. Some detrimental effects on ladybird beetles were also caused by white thyme essential oil, sweet orange essential oil and Marseille soap. Additionally, although pyrethrins have a broader spectrum of insecticidal activity compared to most botanical insecticides, they had no significant adverse effect on adult ladybird beetles and parasitoids within aphid mummies, similar to most of the other tested natural products. Botanical insecticides and soaps are frequently proposed as environmentally safer alternatives to synthetic insecticides. However, the efficacy and selectivity of these products are often only partially supported by empirical evidence. Here, we tested the effectiveness of five botanical insecticides, belonging to different categories, on the green peach aphid Myzus persicae (Sulzer) and their selectivity towards two natural enemies, the ladybird beetle Propylea quatuordecimpunctata (L.) and the parasitoid Aphidius colemani (Dalman). White thyme essential oil (EO), sweet orange EO, crude garlic extract and Marseille soap were tested and compared with a pyrethrin-based commercial product. Both direct spray assays and residual contact assays on treated cabbage leaf disks were carried out. The tested products had low efficacy against aphids when compared to pyrethrins but were in general less detrimental to ladybird beetle larvae, meaning that if applied against other pests, they have a lower chance of harming this agent of aphid biocontrol. Some of the products (soap, orange EO) did, however, show direct exposure toxicity toward ladybird larvae, and thyme EO had extensive phytotoxic effects on cabbage leaves, possibly indirectly leading to higher mortality in ladybird adults. These results underline the necessity for case-by-case evaluations of botanical insecticides. [ABSTRACT FROM AUTHOR]

Botanical insecticides and soaps are frequently proposed as environmentally safer alternatives to synthetic insecticides. However, the efficacy and selectivity of these products are often only partially supported by empirical evidence. Here, we tested the effectiveness of five botanical insecticides, belonging to different categories, on the green peach aphid Myzus persicae (Sulzer) and their selectivity towards two natural enemies, the ladybird beetle Propylea quatuordecimpunctata (L.) and the parasitoid Aphidius colemani (Dalman). White thyme essential oil (EO), sweet orange EO, crude garlic extract and Marseille soap were tested and compared with a pyrethrin-based commercial product. Both direct spray assays and residual contact assays on treated cabbage leaf disks were carried out. The tested products had low efficacy against aphids when compared to pyrethrins but were in general less detrimental to ladybird beetle larvae, meaning that if applied against other pests, they have a lower chance of harming this agent of aphid biocontrol. Some of the products (soap, orange EO) did, however, show direct exposure toxicity toward ladybird larvae, and thyme EO had extensive phytotoxic effects on cabbage leaves, possibly indirectly leading to higher mortality in ladybird adults. These results underline the necessity for case-by-case evaluations of botanical insecticides.

The pupal parasitoid Tetrastichus howardi (Olliff) (Hymenoptera: Eulophidae) parasitizes pupae of sugarcane stalk borers inside the stalk. Parasitoids currently used for applied biological control of sugarcane stalk borers target eggs and larvae, and T. howardi will add mortality to the pest stage with high survival. Nevertheless, insecticide applications required to control sugarcane borers and other sugarcane pests can affect T. howardi parasitism. Survival, walking, evasion and parasitism of T. howardi females were evaluated in response to the dry residue of insecticides from different chemical groups: chlorantraniliprole, bifenthrin, spinetoram, ethiprole, fipronil and thiamethoxam. Females of the parasitoid were confined on sugarcane leaves containing residues of the insecticides at 2, 24, 48, 72 and 96 h intervals after application, and survival monitored during the 96‐h period with subsequent determination of parasitism in the laboratory. Furthermore, female walking behaviour was observed individually using half‐treated arenas with insecticides. Chlorantraniliprole was compatible with T. howardi irrespective of residual intervals and studied variables. Other tested insecticides did not allow parasitoid survival up to 96 h of confinement on dry residues and, consequently, parasitism. Locomotory activity indicated that parasitoid females might avoid residues of spinetoram and ethiprole. Females were released in cages containing spinetoram and ethiprole‐treated sugarcane plants with the chance to move to untreated plants, parasitized pupae placed on either treated or untreated plants within a 24 h exposure period, which resulted in offspring production. Females observed for 10 min for walking behaviour in a half‐treated arena with chlorantraniliprole, ethiprole, fipronil, spinetoram, bifenthrin or thiamethoxam exhibited 100%, 73.3%, 70%, 66.7%, 10% and 0% survival after 24 h, respectively. Chlorantraniliprole was compatible with T. howardi through the bioassays conducted, and parasitoids showed the ability to parasitize their hosts on spinetoram‐ and ethiprole‐treated plants moving away from the treated environment. [ABSTRACT FROM AUTHOR]

Soybean production is usually performed on large scales, requiring simple but efficient pest management to be successful. Soybean fields are inhabited by several species of arthropods, demanding constant development of management practices to prevent pest outbreaks. More recently, stink bugs have become the most important pest group of soybeans in the Neotropics, responsible for up to 60% of the applied insecticides in Brazil. Natural enemies represent an important mortality factor that can keep the damage caused by stink bugs below the economic threshold levels without additional control actions. Thus, Conservation Biological Control (CBC) strategies can be adopted to preserve or even promote the increase in such natural enemies in the fields, or alternatively, massive releases of biocontrol agents in Augmentative Biological Control (ABC) programs could be adopted. Simple practices such as reducing insecticide use (with the adoption of economic thresholds), prioritizing harmless insecticides or biopesticides, and planting resistant soybean cultivars have been adopted in Brazil with positive results. The challenges to increasing the adoption of more complex stink bug management in commodity crops such as soybean may be overcome using the more recent economic incentives in the global agenda of decarbonized agriculture. The potential and challenges of conservation and augmentative biological control are further discussed in this review. [ABSTRACT FROM AUTHOR]

Conservation biological control techniques support integrated pest management (IPM) and insecticide resistance management (IRM) by restraining pest resurgence and outbreaks of secondary pests. The lady beetle Eriopis connexa (Germar) (Coleoptera: Coccinellidae) is among the natural enemies in agricultural systems of brassica crops and their populations may be disrupted by exposure to insecticides. Pyrethroid-resistant and pyrethroid-susceptible E. connexa larvae and adults were exposed to eight insecticides (cyantraniliprole, chlorantraniliprole, chlorfenapyr, deltamethrin, spinosad, spiromesifen, methomyl, and pymetrozine) that target different pests of brassica crops. Evaluations were conducted on larval and adult survival, larval developmental time, fecundity and egg viability across 30 days, and consumption of Lipaphis pseudobrassicae (Davis) (Hemiptera: Aphididae) or larvae of Plutella xylostella (L.) (Lepidoptera: Plutellidae) during the exposure to the insecticides. In addition, the levels of aphids and diamondback moths infestation in field cages were evaluated as a function of insecticide application and release of the lady beetles. Neither survival of larvae and adult beetles, nor fecundity, were affected by the insecticides. Surviving lady beetles from pyrethroid-resistant and pyrethroid-susceptible populations consumed aphids and diamondback moth larvae when exposed simultaneous to the insecticides targeting these pest species. There was no additive effect of the control of these pests when lady beetles were used alone or with insecticides. The findings showed the compatibility of this natural enemy with selected insecticides through multiple exposures targeting different pest species combining different insecticide modes of action. [ABSTRACT FROM AUTHOR]

The parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) is often released to manage lepidopteran pests in cotton crops. However, growers rely on multiple insecticide applications to manage cotton pests. A harmonious integration of control tactics is required for proper pest management, and the use of selective insecticides (i.e., those promoting effective pest control while causing little impact on natural enemies) fits within this scope. This study aimed to assess the lethal, sublethal and transgenerational effects of insecticides from varying chemical groups on T. pretiosum. The insecticides were sprayed on parasitized host [Ephestia kuehniella (Zeller), Lepidoptera: Pyralidae] eggs with developing T. pretiosum stages (egg-larva, prepupa, and pupa), and biological traits were assessed following adult emergence. Overall, pupae were more susceptible to insecticides. We found thiodicarb and chlorfenapyr to reduce F0 adult emergence in rates comparable to the positive control (methomyl). Adult F0 deformation was the highest on flupyradifurone-treated organisms, and both the F0 parasitism rate and female survival were reduced by the insecticides (except for teflubenzuron). The sex ratio (proportion female) was affected by thiodicarb and flupyradifurone. Transgenerational effects occurred on adult emergence, which was reduced on the offspring (F1) of thiodicarb, chlorfenapyr, and flupyradifurone treated T. pretiosum. In addition, thiodicarb decreased the F1 sex ratio (≤ 0.33) compared to the other compounds (sex ratio ≥ 0.45). These results indicate that teflubenzuron is the safest insecticide; the other insecticides are non-selective to T. pretiosum. Field and semifield studies are required to confirm the harmfulness of chlorfenapyr, flupyradifurone and thiodicarb toward T. pretiosum. [ABSTRACT FROM AUTHOR]

Soybean production is usually performed on large scales, requiring simple but efficient pest management to be successful. Soybean fields are inhabited by several species of arthropods, demanding constant development of management practices to prevent pest outbreaks. More recently, stink bugs have become the most important pest group of soybeans in the Neotropics, responsible for up to 60% of the applied insecticides in Brazil. Natural enemies represent an important mortality factor that can keep the damage caused by stink bugs below the economic threshold levels without additional control actions. Thus, Conservation Biological Control (CBC) strategies can be adopted to preserve or even promote the increase in such natural enemies in the fields, or alternatively, massive releases of biocontrol agents in Augmentative Biological Control (ABC) programs could be adopted. Simple practices such as reducing insecticide use (with the adoption of economic thresholds), prioritizing harmless insecticides or biopesticides, and planting resistant soybean cultivars have been adopted in Brazil with positive results. The challenges to increasing the adoption of more complex stink bug management in commodity crops such as soybean may be overcome using the more recent economic incentives in the global agenda of decarbonized agriculture. The potential and challenges of conservation and augmentative biological control are further discussed in this review.

Background: Selective tools, including selective insecticides and transgenic cotton, have been crucial in reducing insecticide usage within the integrated pest management (IPM) plan for Arizona cotton. To guide growers effectively, cotton field trials evaluated the effects of the novel insecticides, isocycloseram and afidopyropen against our primary pests, Bemisia argentifolii and Lygus hesperus, and their impacts on nontarget arthropods, including key predators: Collops spp., Orius tristicolor, Geocoris spp., Misumenops celer, Drapetis nr. divergens and Chrysoperla carnea s.l. Assessments involved over 27 arthropod taxa through community analyses, individual predator abundance, and biological control function via predator to prey ratios and a sentinel prey method. Comparisons were made with an untreated check, a proven fully selective insecticide (flonicamid) and acephate-treated positive controls., Results: Overall, relative to the untreated check, afidopyropen showed no significant differences, whereas isocycloseram exhibited some negative impacts, primarily reducing M. celer and Geocoris spp. nymphs, yet it was less detrimental compared with the positive control, acephate, and it did not affect four of the six key predators and most nontarget arthropods., Conclusion: Afidopyropen was classified as a fully selective insecticide and isocycloseram as a partially selective insecticide. Their fit for conservation biological control in Arizona cotton IPM and similar systems is discussed. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd., (© 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.)

The egg parasitoid Telenomus remus (Hymenoptera: Platygastridae) is one of the most important natural enemies of Spodoptera frugiperda (Lepidoptera: Noctuidae). The application of chemical insecticides is the main strategy to control this insect pest, although it can affect T. remus and harm integrated pest management (IPM) programmes. This study evaluated the acute lethal (mortality) and sublethal (parasitism and emergence rate, sex ratio, and longevity) effects caused by chlorfenapyr, spinosad, and thiamethoxam + lambda-cyhalothrin by tarsal contact on T. remus adults. The lethal concentration (LC50) of the insecticides showed that thiamethoxam + lambda-cyhalothrin had the highest lethal toxicity on T. remus adults. However, sublethal effects on the F0 generation showed that all insecticides (chlorfenapyr, spinosad, and thiamethoxam + lambda-cyhalothrin) were classified as innocuous, without significant differences in the parasitism rate, emergence rate, and sex ratio compared to the control. Nevertheless, the risk quotient (RQ, mg ai L−1) classified the insecticides thiamethoxam + lambda-cyhalothrin and chlorfenapyr as toxic to T. remus. In contrast, spinosad was classified as slightly to moderately toxic. Also, thiamethoxam + lambda-cyhalothrin, chlorfenapyr, and spinosad did not affect the biological development of T. remus. These results can be used as a basis for integrating chemical and biological control to manage S. frugiperda in an attempt to preserve natural enemies in the field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluralaner partition in POPC:CHOL and POPC:POPE membranes. • Fluralaner modifies the mechanical properties of membranes reducing film rigidity. • The increase of CHOL affects fluralaner solubility. • Membrane composition could regulate insecticide selectivity in vertebrates and invertebrates. GABA A receptors (GABA A -R) are the target of widely used gabaergic insecticides such as fluralaner, a second generation non-competitive antagonist. Fluralaner blocks GABA A -R, binding to a pocket in the transmembrane subunit interface. Because of the location of its binding pocket, it is expected that fluralaner accesses to the receptor by previously partitioning into the bilayer. Therefore, differences in lipid composition of insect and mammal cells become relevant to determine the impact of membrane composition on the nonspecific selectivity of gabaergic insecticides. Insect cells show minimal concentration of cholesterol and they modulate membrane fluidity by regulating PE:PC ratios. On the other hand, vertebrate cholesterol concentration can be as high as 50%, depending on the type of cell. We used experimental Langmuir monolayer and Molecular Dynamics Simulations (MDS) to characterize the effect and interactions of the insecticide fluralaner with model membranes with varying concentrations of POPC:POPE and POPC:CHOL. Monolayer experiments showed that this insecticide reduces film rigidity. MDS showed that fluralaner is located at the interface between the acyl chain and the polar region of the membrane, but this location shifts at high CHOL concentrations towards the phosphate region. This is accompanied by a shift in the orientation of the fluralaner backbone, affecting fluralaner solubility. The presence of CHOL favors fluralaner aggregation, while POPE has the opposite effect, allowing its solubilization and the presence of individual insecticide molecules homogeneously dispersed. Our work suggests that differences in membrane composition could unspecifically influence the selectivity of gabaergic insecticides, modulating fluralaner solubility and fluralaner's access to GABA A -R. [ABSTRACT FROM AUTHOR]

The present study evaluated the compatibility of the insecticide fipronil with entomopathogenic fungi, in vitro. The compatibility betwee fipronil and entomopathogenic fungi was based on vegetative growth and sporulation of seven isolates of fungi. The studied isolates were three from Beauveria bassiana, one from Cordyceps fumosorosea, and three from Metarhizium anisopliae, and four concentrations of fipronil (0.2, 0.4, 0.6, and 0.8 g L-1), added in PDA (potato-dextrose-agar) culture medium. After 15 days, the colony diameter was measured and the spores were recorded. There was a reduction in the vegetative growth of the isolates at concentration of 0.8 g L-1 of fipronil. For the isolates of B. bassiana and M. anisopliae, there was a decrease in spore production when added the concentrations above 0.4 g L-1 of fipronil; and for C. fumosorosea, spore production decreased when fipronil concentrations were greater than 0.6 g L-1. The insecticide fipronil was classified as "compatible" in terms of toxicity in vitro for tested fungi isolates depending on its concentration. The combination of the insecticide fipronil with the entomopathogenic fungi isolates tested is possible at concentrations below 0.6 g L-1. [ABSTRACT FROM AUTHOR]

Control failure of pests and selectivity of insecticides to beneficial arthropods are key data for the implementation of Integrated Pest Management (IPM) programs. Therefore, the aim of this study was to assess the control failure likelihood of Plutella xylostella and the physiological selectivity active ingredients to parasitoid Oomyzus sokolowskii (Hymenoptera: Eulophidae) and to predators Polybia scutellaris (Hymenoptera: Vespidae) and Lasiochilus sp. (Hemiptera: Anthocoridae). In bioassays, P. xylostella larvae and O. sokolowskii, P. scutellaris and Lasiochilus sp. adults were used. Concentration-mortality curves of six insecticides for P. xylostella were established. These curves were used to estimate the mortality of P. xylostella at the recommended concentration, in order to check a control failure of insecticides to this pest. Furthermore, the lethal concentration for 90% of populations (LC90) and the half of LC90 were used in bioassays with the natural enemies to determine the selectivity of these insects to insecticides. All tested insecticides showed control failure to P. xylostella, indicated by high LC90 and low estimated mortalities (less than 80%). The cartap insecticide was selective in half of LC90 to Lasiochilus sp. and moderately selective in LC90 and the half of LC90, to Lasiochilus sp. and P. scutellaris, respectively. Deltamethrin was moderately selective in the half of LC90 to predator Lasiochilus sp. Cartap, carbaryl, and deltamethrin reduced the mortality of Lasiochilus sp. in the half LC90. The results also showed that the insecticides methamidophos, carbaryl, parathion methyl and permethrin were not selective to any of the tested natural enemies. The role of insecticides in IPM systems of Brassica crops is discussed based on their control failures to P. xylostella and selectivity to their natural enemies.

When applied one month before detectible natural enemy activity, insecticides did not reduce their total seasonal abundance. In contrast, when applied later in the season at the cusp of the wave of natural enemy activity, insecticide affected their abundance according their selective toxicity. Arrows indicate time of application. • Use of seasonal phenology conserves beneficials in integrated management plans. • Seasonal phenology of natural enemies corresponds with biology of scale hosts. • Timing of pesticides should consider seasonal phenology of scale natural enemies. • Reduced risk insecticides could be considered when natural enemies are active. • Bifenthrin was more toxic than all reduced-risk insecticides to natural enemies. Scale insects (Hemiptera: Coccoidea) are among the most problematic pests of woody plants in protected culture and urban landscapes. When outbreaks of scale insects occur, insecticides are often applied to reduce host damage. To select reduced risk insecticides that can complement the mortality contributed by natural enemies, the selectivity and residual toxicity of each insecticide must be considered within the context of the seasonal biology of both the pest and its natural enemies. We studied how timing of applying reduced risk insecticides affected the natural enemies of scales in relation to their life histories and seasonal abundance. This study was conducted on trees that were naturally infested with either the soft scale, calico scale Eulecanium cerasorum (Cockerell) or armored scales, striped pine scale Toumeyella pini (King) and pine needle scale Chionaspis pinifoliae (Fitch). Insecticides were applied to target the most susceptible life stages of each scale insect. We found that patterns of the seasonal abundance of natural enemies were synchronized with the life history of each scale insect and took the shape of a rising and falling wave. Overall, impacts of insecticides on parasitoids and predators were influenced by the timing of their applications in relation to when natural enemy abundance began to rise at the cusp of their wave of abundance. Application one month prior to this cusp did not reduce seasonal totals of natural enemy abundance, regardless of insecticide selectivity or residual toxicity. In contrast, when applications were made at the cusp of the natural enemy wave, foliar applications of bifenthrin had greater adverse side effects on natural enemy populations compared to foliar applications of pyriproxifen, spirotetramat, spiromesifin, and chlorantraniliprole or a soil application of dinotefuran. We present evidence to suggest that restricting applications during the cusp of the natural enemy activity wave can result in a better integration of chemical and biological control. [ABSTRACT FROM AUTHOR]

Control failure of pests and selectivity of insecticides to beneficial arthropods are key data for the implementation of Integrated Pest Management (IPM) programs. Therefore, the aim of this study was to assess the control failure likelihood of Plutella xylostella and the physiological selectivity active ingredients to parasitoid Oomyzus sokolowskii (Hymenoptera: Eulophidae) and to predators Polybia scutellaris (Hymenoptera: Vespidae) and Lasiochilus sp. (Hemiptera: Anthocoridae). In bioassays, P. xylostella larvae and O. sokolowskii, P. scutellaris and Lasiochilus sp. adults were used. Concentration-mortality curves of six insecticides for P. xylostella were established. These curves were used to estimate the mortality of P. xylostella at the recommended concentration, in order to check a control failure of insecticides to this pest. Furthermore, the lethal concentration for 90% of populations (LC90) and the half of LC90 were used in bioassays with the natural enemies to determine the selectivity of these insects to insecticides. All tested insecticides showed control failure to P. xylostella, indicated by high LC90 and low estimated mortalities (less than 80%). The cartap insecticide was selective in half of LC90 to Lasiochilus sp. and moderately selective in LC90 and the half of LC90, to Lasiochilus sp. and P. scutellaris, respectively. Deltamethrin was moderately selective in the half of LC90 to predator Lasiochilus sp. Cartap, carbaryl, and deltamethrin reduced the mortality of Lasiochilus sp. in the half LC90. The results also showed that the insecticides methamidophos, carbaryl, parathion methyl and permethrin were not selective to any of the tested natural enemies. The role of insecticides in IPM systems of Brassica crops is discussed based on their control failures to P. xylostella and selectivity to their natural enemies. [ABSTRACT FROM AUTHOR]

Copidosoma truncatellum (Hymenoptera: Encyrtidae) is an important parasitoid wasp of the soybean looper, Chrysodeixis includens , but its effectiveness can be severely curtailed by the application of certain insecticides. Therefore, to identify insecticides that are potentially compatible with C. truncatellum , the lethal and behavioral effects of nine chemicals used to control the soybean looper were evaluated for their toxicity to the wasp. Chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb were the least toxic insecticides to the parasitoid, resulting in mortalities of less than 25%. In contrast, cartap, deltamethrin, and methomyl caused 100% mortality, and acephate and spinosad caused 76% and 78% mortality, respectively. At least one of the detoxifying enzymes (monooxygenase, glutathione S-transferase, and/or esterases) may be involved in the mechanisms underlying the selectivity of chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb for the parasitoid based on the results for the insecticide plus synergist treatment. Changes in the behavioral patterns (walking time and resting time) of the parasitoid were found with exposure to acephate, flubendiamide, indoxacarb and methomyl, but behavioral avoidance was not observed. Our results indicate that the insecticides chlorantraniliprole and chlorfenapyr are the most suitable for inclusion in integrated pest management strategies for the control of C. includens . [ABSTRACT FROM AUTHOR]

The mirid bug, Cyrtorhinus lividipennis Reuter, an important predatory natural enemy of rice planthoppers, is widely distributed in rice fields. However, genetic information on C. lividipennis is lacking. Especially, limited data about mechanisms of insecticide selectivity between this piercing-sucking predator ( C. lividipennis ) and piercing-sucking preys (rice planthoppers), inhibits development of selective insecticides and the integration of chemical and biological control systems to control insect pests of rice. Hence, we performed de novo assembly of a transcriptome from adult and nymph whole bodies of C. lividipennis . A total of > 29 million of reads were generated, and 34,752 transcripts matched known proteins. Then, the genes related to insecticide action and detoxification were manually identified, including 26 carboxylesterases (containing 2 acetylcholinesterases), 57 cytochrome P450s, 19 glutathione S-transferases, 15 nicotinic acetylcholine receptors, 3 GABA-gated ion channels, and 1 glutamate receptor. Comparisons of sequence differences in these genes between C. lividipennis and rice planthoppers, revealed that quite a lot of diversity was found among genes related to insecticide action and detoxification, while a few of these genes share much higher identities between this predator and prey. The present study provides useful information for our understanding of insecticide selectivity between rice planthoppers and the predator mirid bug. [ABSTRACT FROM AUTHOR]

Foliage- and ground-dwelling arthropods provide ecosystem services, including decomposition and biological control of agricultural pests. Despite this, there is little information on the ground-dwelling arthropod community associated with cotton crops and about their role under pest control practices. Identifying these communities and their preservation would assist smallholder cotton growers in considering an Integrated Pest Management (IPM) approach to pest control. In this context, the strategy of using selective- or broad-spectrum insecticides (both applied only once the pests reached an economic threshold) was assessed using field plots set up within non-Bt cotton structured refuge of a grower field measuring the response of both foliage- and ground-dwelling arthropods and yield. The abundance, species richness, dominance indices, and foliage-dwelling predators and pest species and ground-dwelling predators and decomposers were compared between untreated and insecticide treatments, as was the crop yield. In response to pest monitoring, insecticides were applied 5 and 3 times during the 2018 and 2020 growing seasons, respectively. In 2018 and 2020, 16 and 12 foliage-dwelling predator arthropods and 43 and 47 ground-dwelling predator and decomposer arthropods were collected, respectively. During the 2018 season, broad-spectrum insecticide applications reduced the abundance of foliage-dwelling predators, but had no significant impact on the ground-dwelling community. Principal response curves (PRC) indicated a negative impact of broad-spectrum insecticides only on the foliage-dwelling community, particularly among the Formicidae and Araneae species. Insecticide applications in the 2020 season were only required at the end of the crop season and did not significantly influence the foliage- or ground-dwelling communities. The selective insecticide regime yielded as well as the broad-spectrum insecticide regimes higher yielded than untreated plots. These results demonstrated to the small landholders engaging conservation biological control for the first time, the advantages of an IPM approach to pest management. [Display omitted] • Cotton growers in the Brazilian semiarid operate a distinctive farming system. • The cotton yield is limited by rain, lack of adapted technologies, and pest damage. • Insecticides applied only when pest densities reached the economic threshold reduced the impact on beneficial arthropods. • Selective insecticides preserved foliage and ground dwelling arthropods and yield. • The data encourage growers be receptive to a more comprehensive IPM approach in the region. [ABSTRACT FROM AUTHOR]

The use of botanical insecticides could be an alternative efficient pest management in Cucurbitaceae against melonwormDiaphania hyalinataand less harmful to its predator. Few studies jointly assess the efficiency of botanical insecticides, their effects on pest, and their effect on the natural enemy and target crop. Here we examine (1) their impact against the melonwormD. hyalinata, a key pest of Cucurbitaceae, (2) their toxicity to the predatory antParatrechinasp., and (3) their phytotoxicity to pumpkin plants. The botanical insecticides citronella oil and eucalyptus oil were highly toxic toD. hyalinataand they exhibited to be less harmful for the predatory antParatrechinasp. Andiroba oil, eucalyptus oil, garlic extract, and citronella oil caused feeding inhibition of theD. hyalinatalarvae. Eucalyptus oil, andiroba oil, garlic extract, and rotenone inhibited the oviposition ofD. hyalinata. None of the insecticides was phytotoxic to pumpkin plants. Eucalyptus oil and citronella oil have induced high mortality and altered the behavior of target pests. In addition, they were selective for the predatorParatrechinasp. and not exhibited phytotoxicity on pumpkin plants. Eucalyptus oil and citronella oil seem the most promising compounds for incorporation into melonworm management programs, because they induced high mortality and altered the behavior of target pests and were selective for the predatorParatrechinasp. [ABSTRACT FROM PUBLISHER]

Lethal and sublethal insecticide effects on non-targeted pest species are frequently neglected but have potential consequences for pest management and secondary pest outbreaks. Here, the lethal and demographic effects of four soybean insecticides (chlorantraniliprole, deltamethrin, pyriproxyfen, and spinosad, which are used against caterpillars, whiteflies, and green stink bugs) on the brown stink bug Euschistus heros (F.), the main stink bug species currently attacking Neotropical soybean fields, were assessed. Deltamethrin exhibited drastic acute mortality in adult females of E. heros with a median lethal time (LT 50 ) of 0.6 days, whereas pyriproxyfen treated females exhibited a survival similar to that of water-treated insects (LT 50 of 89 and 67 days, respectively). Chlorantraniliprole and spinosad-treated females exhibited intermediate survival with a TL 50 of 54 and 47 days, respectively. Further scrutiny of the three most selective insecticides (i.e., chlorantraniliprole, pyriproxyfen, and spinosad) using age-structured matrices to assess the demographic impact of these compounds under earlier exposure indicated that both pyriproxyfen and spinosad significantly reduced the population growth of the pest species by compromising the survival of eggs (<17% hatching) and 1st nymphs (LT 50 of 3 and 2 days, respectively) and fertility; these results were unlike those obtained for chlorantraniliprole- and water-treated controls, which exhibited less than 50% mortality during development. However, chlorantraniliprole significantly compromised the fertility of adult insects (>50% reduction compared with water-treated insects) to a greater extent than pyriproxyfen and spinosad, but without impairing insect population growth as much. Therefore, although pyriproxyfen and spinosad, besides deltamethrin, are not used to target the Neotropical brown stink bug, these insecticides adversely affected this pest species at the dose recommended for application on the label, thereby preventing its outbreak under such conditions. [ABSTRACT FROM AUTHOR]

The objective of this work was to study the toxicity of pymetrozine and thiamethoxam to the cotton aphid parasitoid Aphelinus gossypii Timberlake and to the whitefly predator Delphastus pusillus (LeConte). Cotton leaves containing mummies of the parasitoid A. gossypii were collected and treated with seven concentrations of both insecticides. Parasitoid emergence was not affected by pymetrozine and ranged from 59.9% to 75.0%, but decreased with the increase of thiamethoxam concentrations ranging from 30.2% to 69.6%. Cotton leaves infested by whitefly and treated with recommended rates of both insecticides were collected three hours, three days and six days after spraying and colonized with larvae and adults of D. pusillus. Predators released on thiamethoxam-treated leaves experienced mortality from 70% to 100%, while those released on pymetrozine-treated leaves showed mortality from 0% to 20%. Topical toxicity from both insecticides was studied on larvae, pupae and adults of D. pusillus. The survival of predator after six days of exposure to 400, 600 and 800 mg/L of pymetrozine a.i. was higher than 69.6%, and to 25, 100 and 200 mg/L of thiamethoxam a.i. was lower than 8.7%. The toxicity data for A. gossypii and D. pusillus characterize the pymetrozine as harmless for both species, and thiamethoxam of low to moderate toxicity for A. gossypii treated mummies, and high toxicity for D. pusillus.

Abstract: Pardosa pseudoannulata is an important predatory enemy against insect pests, such as rice planthoppers and leafhoppers. In order to understand the insecticide selectivity between P. pseudoannulata and insect pests, two acetylcholinesterase genes, Pp-ace1 and Pp-ace2, were cloned from this natural enemy. The putative proteins encoded by Pp-ace1 and Pp-ace2 showed high similarities to insect AChE1 (63% to Liposcelis entomophila AChE1) and AChE2 (36% to Culex quinquefasciatus AChE2) with specific functional motifs, which indicated that two genes might encode AChE1 and AChE2 proteins respectively. The recombinant proteins by expressing Pp-ace1 and Pp-ace2 genes in insect sf9 cells showed high AChE activities. The kinetic parameters, V max and K m , of two recombinant AChE proteins were significantly different. The sensitivities to six insecticides were determined in two recombinant AChEs. Pp-AChE1 was more sensitive to all tested insecticides than Pp-AChE2, such as fenobucarb (54 times in K i ratios), isoprocarb (31 times), carbaryl (13 times) and omethoate (6 times). These results indicated that Pp-AChE1 might be the major synaptic enzyme in the spider. By sequence comparison of P. pseudoannulata and insect AChEs, the key amino acid differences at or close to the functional sites were found. The locations of some key amino acid differences were consistent with the point mutation sites in insect AChEs that were associated with insecticide resistance, such as Phe331 in Pp-AChE2 corresponding to Ser331Phe mutation in Myzus persicae and Aphis gossypii AChE2, which might play important roles in insecticide selectivity between P. pseudoannulata and insect pests. Of course, the direct evidences are needed through further studies. [Copyright &y& Elsevier]

Highlights: [•] Amblyseius herbiculus is more tolerant to deltamethrin than its prey O. ilicis. [•] The predator A. herbiculus do not exhibit avoidance to deltamethrin. [•] Low doses of deltamethrin induced hormesis in the red mite O. ilicis. [•] Deltamethrin-induced hormesis in O. ilicis is a likely cause of its outbreaks. [Copyright &y& Elsevier]

Abstract: The parasitic wasp Trichogramma nubilale (Hymenoptera: Trichogrammatidae) is one of the most suitable parasitoids for controlling Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae). Although extensive toxicological tests have been carried out to elucidate the toxicities of insecticides to trichogrammatids, the acute toxicity risks of commonly used insecticides to T. nubilale are not well known. Among the 7 classes of tested chemicals, organophosphates and carbamates had the highest intrinsic toxicity to the parasitoid with LC50 values ranging from 0.081 (0.062–0.12) to 2.10 (1.23–3.47) and from 0.12 (0.11–0.14) to 0.95 (0.87–1.05) mg a.i. per liter, respectively. The phenylpyrazoles (with the exception of butene-fipronil), avermectins, neonicotinoids and pyrethroids induced intermediate toxicity responses with LC50 values ranging from 0.29 to 4.67, 2.36 to 11.27, 1.86 to 311.9, and 10.98–150.3 mg a.i. per liter, respectively. In contrast, insect growth regulators (IGRs) exhibited the least toxicity to the parasitoid with LC50 values ranging from 3452 (3114–3877) to 10,168 (8848–12,027) mg a.i. per liter. A risk quotient analysis indicated that neonicotinoids, avermectins, pyrethroids, IGRs and phenylpyrazoles (with the exception of butene-fipronil) were safe, but organophosphates and carbamates were slightly to moderately toxic or highly toxic to T. nubilale. This study provided informative data for implementing both biological and chemical control strategies in integrated pest management (IPM) of corn lepidopterans. [Copyright &y& Elsevier]

Control of the invasive vine mealybug Planococcus ficus (Signoret) can be achieved through integration of different management strategies such as the application of chemical treatments and biological control. However, compatibility between these control methods is considered crucial when adopting integrated pest management (IPM) programs against this insect pest. The recently used insecticides Prev-Am®, a contact biopesticide, and spirotetramat, a systemic tetramic acid insecticide, were assessed in laboratory conditions for their side effects on the vine mealybug parasitoid Anagyrus sp. near pseudococci with reference to chlorpyriphos-methyl, an organophosphate insecticide conventionally used for mealybug control in vineyards. Regarding contact toxicity, chlorpyriphos-methyl caused 100% parasitoid mortality 24 h after treatment, but parasitoid mortality from Prev-Am® or spirotetramat was almost absent. Neither the total parasitoid offspring/female nor the sex ratio of the progeny was negatively affected by Prev-Am® or spirotetramat relative to the untreated control. According to the IOBC classification for laboratory trials, both Prev-Am® and spirotetramat were rated harmless (IOBC category 1), whereas chlorpyriphos-methyl was categorized as harmful (IOBC category 4) to A. sp. near pseudococci. None of the insecticides adversely affected the development of the parasitoid pupal stage inside mealybug mummies or the survival of the emerged parasitoids. The practical implications of the results for implementing mealybug IPM programs in vineyards are emphasized and discussed. [ABSTRACT FROM AUTHOR]

The use of a selective insecticide is highly recommended for Integrated Pest Management programs. Plenum (a.i.: pymetrozine; Syngenta Agro), a systemic insecticide, is regarded as a good candidate for use in situations where plant-sucking insects have to be controlled and where natural enemies can play a substantial role as biological control agents. In this context, the effects of Plenum on a host-endoparasitoid relationship were investigated. Potato aphids Macrosiphum euphorbiae were reared for 4 days on an artificial diet supplemented with a low concentration of Plenum (sublethal concentration inducing 15% aphid mortality) before parasitization by the endoparasitoid Aphidius ervi. The development of A. ervi larvae was negatively affected, especially during the early stages of development, and the sex ratio of the progeny was strongly male-biased. Moreover, the host-choice experiment showed that A. ervi was not able to discriminate between control and Plenum-contaminated aphids. These results show that Plenum may not be as selective as it was previously thought to be, and the observed effects need to be considered when developing IPM systems. [ABSTRACT FROM AUTHOR]

The cytochrome P450 family (P450s) of arthropods includes diverse enzymes involved in endogenous essential physiological functions and in the oxidative metabolism of xenobiotics, insecticides and plant allelochemicals. P450s can also establish insecticide selectivity in bees and pollinators. Several arthropod P450s, distributed in different phylogenetic groups, have been associated with xenobiotic metabolism, and some of them have been functionally characterized, using different in vitro and in vivo systems. The purpose of this review is to summarize scientific publications on arthropod P450s from major insect and mite agricultural pests, pollinators and Papilio sp , which have been functionally characterized and shown to metabolize xenobiotics and/or their role (direct or indirect) in pesticide toxicity or resistance has been functionally validated. The phylogenetic relationships among these P450s, the functional systems employed for their characterization and their xenobiotic catalytic properties are presented, in a systematic approach, including critical aspects and limitations. The potential of the primary P450-based metabolic pathway of target and non-target organisms for the development of highly selective insecticides and resistance-breaking formulations may help to improve the efficiency and sustainability of pest control. [Display omitted] • Pest and pollinator P450s functionally associated with detoxification are reviewed. • P450s associated with xenobiotic detoxification belong to clan 3, but no particular clade. • The systems used for P450 functional validation are critically summarised and presented. • The substrate specificities of different arthropod P450s are summarised. • P450-based metabolic pathway provides potential for safe and selective insecticides. [ABSTRACT FROM AUTHOR]

The article presents a study on the insecticides' toxicity to the sweetpotato whitefly (Hemiptera: Aleyrodidae) and its natural enemies. It notes that to know the insecticide toxicity, B. tabaci adults were exposed to acephate, abamectin, cartap, and malathion, and to determine its selectivity, adults of Acanthinus sp., Encarsia ap., and Lasiochilus sp. were exposed acephate, abamectin, and cartap, and to water. The findings of these test methods show that abamectin and acetamiprid at 100% FR and cartap and imidacloprid at 50 and 100% FR demonstrated insecticidal activity to B. tabaci adults. Results recommends that there will be a decrease in the field populations of B. tabacci due to abamectin at 100% FR but can still be harmless to predators.

In the absence of equivalent research on genetically modified (GM) pest-resistant crops, their impact in pest management can be predicted from experience with traditionally bred varieties which share with GM crops the characteristic that the resistance is based on high expression of a single toxin. Such varieties lead to the rapid selection of tolerant pest strains, damage biological control and induce tolerance to synthetic pesticides. By contrast, polygenic and more broadly based resistant varieties will maintain their resistance for longer, and often synergise beneficially with biological control. The pests also become more susceptible to insecticides, giving the opportunity for applications which are selective in favour of natural enemies. However, although GM crops compare badly with traditional pest-resistant varieties, they compare favourably with insecticides, the technology they are most likely to replace. [ABSTRACT FROM AUTHOR]

The adaptive fitness of insect species can be shaped by how males and females respond, both physiologically and behaviorally, to environmental challenges, such as pesticide exposure. In parasitoid wasps, most toxicological investigations focus only on female responses (e.g., survival and especially parasitism abilities), leaving the male contributions to adaptive fitness (survival, locomotion, mate search) poorly investigated. Here, we evaluated the toxicity of the spinosyn insecticide spinosad against the South American fruit fly, Anastrepha fraterculus , and we used the parasitoid wasp Diachasmimorpha longicaudata (Ashmead) to evaluate whether sex-linked locomotory and physiological responses would influence the susceptibility of these organisms to spinosad. Our results revealed that D. longicaudata males were significantly more susceptible (median lethal time (LT 50) = 24 h) to spinosad than D. longicaudata females (LT 50 = 120 h), which may reflect the differences in their locomotory and physiological (e.g., respiratory) responses to mitigate insecticide exposure. Compared to D. longicaudata females, male wasps were lighter (P < 0.001), walked for longer distances (P < 0.001) and periods (P < 0.001), and exhibited higher sensilla densities in their tarsi (P = 0.008), which may facilitate their intoxication with the insecticide. These findings indicate that male parasitoids should not be exempt from insecticide selectivity tests, as these organisms can be significantly more affected by such environmental challenges than their female conspecifics. Image 1 • Spinosad susceptibility was assessed in both Diachasmimorpha longicaudata sexes. • Females of D. longicaudata were significantly more resitant to spinosad than males. • D. longicaudata males were lighter and walked more than females. • Males of D. longicaudata were significantly more susceptible to spinosad than females. • D. longicaudata males should not be exempt from spinosad selectivity tests. Our findings demonstrate that sex-biased behavioral and physiological responses contributes to differential susceptibilities to insecticides, and thereof environmental consequences, recorded on parasitoid wasps. [ABSTRACT FROM AUTHOR]

ABSTRACT The control of Alphitobius diaperinus is based mainly on chemical insecticides, and the indiscriminate and incorrect use of these products has led to failures in insect control. Thus, it is important to monitor the efficiency of the products available on the market and to develop alternative insect control strategies. The present study evaluated the effect of a new product (cypermethrin-6%) under laboratory and field conditions and assessed its in-vitro compatibility with the fungus Beauveria bassiana (Unioeste 4 isolate). Its efficiency in dry powder and wettable powder formulations was also assessed in the laboratory through comparison with a similar insecticide (cypermethrin-5%) at five different concentrations. The field assays were conducted in two commercial broiler breeder houses (Treated and Control), applying the new product on the litter at the manufacturer's recommended concentration (RC). Germination, vegetative growth, conidial production, number of colony forming units (CFUs) and insecticidal activity of the fungus were used to evaluate the compatibility of the insecticide. The effects of the cypermethrin-6% product and cypermethrin-5% were equivalent in the laboratory, and the new product exhibited better performance at lower concentrations (1/4RC, ⅛RC). The strategy applied in the field reduced the insect population in up to 96% after 75 days. Additionally, all concentrations of cypermethrin-6% were compatible with the fungus under the evaluated in-vitro conditions. Therefore, the new product is considered selective for B. bassiana. Further studies are necessary to assess its compatibility under field conditions, consolidating this strategy as a viable alternative for managing this pest.