Is Integrated Management of Gymnandrosoma aurantianum Possible with Trichogramma atopovirilia and Novel Products Used in Citrus Orchards in Brazil?

In Brazil, the citrus fruit borer, Gymnandrosoma aurantianum Lima, 1927, is a serious pest in orange orchards, causing an annual loss of 80 million US dollars, and is managed with multiple insecticide applications, often 56 in a single season. On the other hand, the parasitoid wasp Trichogramma atopovirilia Oatman & Platner, 1983 has the potential for controlling G. aurantianum by attacking its eggs. Considering the intensive insecticide applications in citrus orchards in Brazil to control the large complex of pests, especially Diaphorina citri Kuwayama, 1908, evaluation of the harmful effects of insecticides on T. atopovirilia is important to maximize efficiency in managing G. aurantianum. Here, we tested the effects of new products used in citrus orchards (cyantraniliprole, cyantraniliprole + abamectin, abamectin, sulfoxaflor, spinetoram, flupyradifure, and Cordyceps fumosorosea (Wize) Kepler, B. Shrestha & Spatafora) on adults and pupae of T. atopovirilia. Of the insecticides tested, spinetoram caused the highest impacts on T. atopovirilia parasitism, longevity, emergence, and mortality. The other products caused more sublethal than lethal effects and were classified as 1 and/or 2 in the IOBC/WPRS classification. Abamectin, cyantraniliprole, cyantraniliprole + abamectin, and the entomopathogenic fungus C. fumosorosea were classified as short-lived. Except for spinetoram, these products were classified as selective. In this study, spinetoram was considered harmful to T. atopovirilia and, therefore, should be managed carefully in IPM programs combining this parasitoid. In order to safely use this insecticide, one should respect the interval of release of the parasitoid, which is 21 days after its spraying. The novel products tested, cyantraniliprole, cyantraniliprole + abamectin, abamectin, sulfoxaflor, and the entomopathogenic fungi C. fumosorosea were selective and non-persistent to T. atopovirilia. These products are possible replacements for non-selective insecticides to achieve higher control from both chemical and biological tools.

Lethal and sublethal effects of an emulsion based on Pogostemon cablin (Lamiaceae) essential oil on the coffee berry borer, Hypothenemus hampei.

The global search for eco-friendly and human-safe pesticides has intensified, and research on essential oils (EOs) has expanded due to their remarkable insecticidal activities and apparent human-safe. Despite this, most of the literature focuses on short-term and simplified efforts to understand lethal effects, with only a few comprehensive studies addressing sublethal exposures. To fill this shortcoming, we explore the lethal and sublethal effects of Pogostemon cablin (Lamiaceae) EO and an EO-based emulsion (18%) using the coffee berry borer Hypothenemus hampei Ferrari (Coleoptera: Curculionidae: Scolytinae) as a model. First, we determine the toxicity of EO and EO-based emulsion using dose-mortality curves and lethal times. Second, we subjected adult females of H. hampei to sublethal doses to assess whether they affected their behavior, reproductive output, and histological features. Our findings reveal that patchoulol (43.05%), α-Guaiene (16.06%), and α-Bulnesene (13.69%) were the main components of the EO. Furthermore, the EO and its emulsion had similar toxicity, with dose-mortality curves and lethal times overlapping 95% confidence intervals. We also observed that sublethal exposure of females of H. hampei reduces reproduction and feeding, increases walking activity, and causes histopathological changes in the midgut. This study advances the knowledge of the lethal and sublethal effects of an eco-friendly substance on insects.Responsible Editor: Giovanni Benelli.

Are Pesticides Used to Control Thrips Harmonious with Soil-Dwelling Predatory Mite Cosmolaelaps sabelis (Mesostigmata: Laelapidae)?

Edaphic predatory mites could be introduced in pest management programs of pests that live, or spend part of their life cycle, in the soil. Some mesostigmatic mites have been widely used for the management of different species of thrips (Thysanoptera), especially in protected cultivation. The edaphic predator Cosmolaelaps sabelis (Mesostigmata: Laelapidae) was a model species in this study, being exposed to the most applied insecticides for the control of thrips in Brazil. After lethal, sublethal and transgenerational effects were evaluated. The pesticides acephate, acetamiprid + etofenprox, azadirachtin, spinetoram, formetanate hydrochloride, and imidacloprid were classified according to the IOBC/WPRS (International Organization for Biological Control-West Paleartic Regional Section) recommendation, considering the acute toxicity and the effects on adult females' reproduction, in the maternal and first generation. The pesticides acetamiprid + etofenprox and azadirachtin were classified as slightly harmful (Class 2), while spinetoram was classified as moderately harmful (Class 3). Acephate and formetanate hydrochloride were classified as harmful (Class 4). Only imidacloprid didn't cause negative effects on the females. Regarding effects on the first generation, acetamiprid + etofenprox, azadirachtin, and spinetoram caused reduction in the oviposition rates. Therefore, we suggest that complimentary bioassays should be done under semi-field and field conditions using the pesticides that were considered harmful in this study, to assess their effects on this predator in other environments prior to recommending not to use them in integrated programs to manage soil-based pests using chemical and biological tools.

The pest-specific effects of glyphosate on functional response of a wolf spider.

Although glyphosate is widely used for weed pest control, it might have negative side effects on natural enemies. Wolf spiders are one of the most representative predators found on soybean crops in Uruguay, preying on a wide variety of potential pests. However, the sublethal effects that pesticides might have on this group have been poorly explored for South American species. Herein, we explored the sublethal effects of glyphosate on the functional response of the wolf spider Hogna cf. bivittata against three potential pest insects, namely ant (Acromyrmex sp.), caterpillar (Anticarsia gemmatalis), and cricket (Miogryllus sp.). We contaminated residually adult females of the species Hogna cf. bivittata with glyphosate (Roundup®) and compared their functional response against non-contaminated spiders. We did not observe any mortality during the study. We found that overall Hogna cf. bivittata showed a functional response type II against crickets and caterpillars but no functional response to ants. Contaminated spiders killed less ants and caterpillars in comparison to the control group, probably as a consequence of the irritating effects of glyphosate. We did not observe differences in functional response to crickets at the evaluated densities, probably as a consequence of the low capture rate against this prey. Although glyphosate does not specifically target spiders, it might have negative sublethal effects on native predators such as Hogna cf. bivittata. Further studies should explore effect of glyphosate on other native predators from South American crops.

Effects of Acaricides on the Functional and Numerical Responses of the Phytoseid Predator Neoseiulus idaeus (Acari: Phytoseiidae) to Spider Mite Eggs.

Integrated control tactics are often necessary for pest management. This is especially true for organisms such as the two-spotted spider mite, Tetranychus urticae Koch. The management of this mite pest species relies on pesticide use, but its short life cycle associated with high selection pressure results in frequent problems of acaricide resistance and population outbreaks. Therefore, combining acaricides and natural enemies is an appealing strategy for managing this pest species. The predatory mite Neoseiulus idaeus Denmark & Muma (Phytoseiidae) is important in arid environments, where other natural enemies show low efficacy. Thus, we investigated the effects of representative acaricides used for managing spider mites around the world in several crops (i.e., abamectin, fenpyroximate, and azadirachtin), on the functional and numerical responses of the phytoseid predator N. idaeus to increasing egg densities of its prey. Acaricide exposure did not affect the type of N. idaeus functional response or attack rate (a). However, acaricide exposure decreased the amount of consumed prey and increased prey handling time (Th). All acaricides affected the numerical response of the predator, which reduced oviposition rates. Therefore, caution is required in attempts to integrate the control methods.

Sublethal effect of Abamectin in the functional response of the predator Phytoseiulus persimilis (Athias-Henriot) on Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae) / Efeito subletal da Abamectina na resposta funcional do predador Phytoseiulus persimilis (Athias-Henriot) em Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae)

Abstract The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a'), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.

Resumo O controle biológico utilizado para o controle de Tetranychus urticae (Koch) é o acaro predador Phytoseiulus persimilis (Athias-Henriot). É importante conhecer os efeitos dos acaricidas sobre o comportamento biológico do predador. Foi avaliado o efeito tóxico de a Abamectina na resposta funcional de P. persimilis. A resposta funcional do predador foi tipo II exposta a concentrações subletais de Abacmetina, os parâmetros da resposta funcional: taxa de ataque (a'), tempo de manipulação (Th), a eficiência na procura e predação teórica máxima (T/Th) foram afetados pelo acaricida. O predador passa mais tempo na procura, dominar, consumir e se preparar para a próxima procura em comparação com a testemunha e sua capacidade de predação foi afetada.

Toxicity and Sublethal Effects of Phthalides Analogs to Rhyzopertha dominica.

Phthalides and their precursors have demonstrated a large variety of biological activities. Eighteen phthalides were synthesized and tested on the stored grain pest Rhyzopertha dominica. In the screening bioassay, compounds rac-(2R,2aS,4R,4aS,6aR,6bS,7R)-7-bromohexahydro-2,4-methano-1,6-dioxacyclopenta[cd]pentalen-5(2H)-one (15) and rac-(3R,3aR,4R,7S,7aS)-3-(propan-2-yloxy)hexahydro-4,7-methano-2-benzofuran-1(3H)-one (17) showed mortality similar to the commercial insecticide, Bifenthrin® (≥90 %). The time (LT50 ) and dose (LD50 ) necessary to kill 50 % of the R. dominica population were determined for the most efficacious phthalides 15 and 17. Compound 15 presented the lowest LD50 (1.97 µg g-1 ), being four times more toxic than Bifenthrin® (LD50 =9.11 µg g-1 ). Both compounds presented an LT50 value equal to 24 h. When applied at a sublethal dose, both phthalides (especially compound 15), reduced the emergence of the first progeny of R. dominica. These findings highlight the potential of phthalides 15 and 17 as precursors for the development of insecticides for R. dominica control.

Sublethal effect of Abamectin in the functional response of the predator Phytoseiulus persimilis (Athias-Henriot) on Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae) / Efeito subletal da Abamectina na resposta funcional do predador Phytoseiulus persimilis (Athias-Henriot) em Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae)

The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.(AU)

O controle biológico utilizado para o controle de Tetranychus urticae (Koch) é o acaro predador Phytoseiulus persimilis (Athias-Henriot). É importante conhecer os efeitos dos acaricidas sobre o comportamento biológico do predador. Foi avaliado o efeito tóxico de a Abamectina na resposta funcional de P. persimilis. A resposta funcional do predador foi tipo II exposta a concentrações subletais de Abacmetina, os parâmetros da resposta funcional: taxa de ataque (a'), tempo de manipulação (Th), a eficiência na procura e predação teórica máxima (T/Th) foram afetados pelo acaricida. O predador passa mais tempo na procura, dominar, consumir e se preparar para a próxima procura em comparação com a testemunha e sua capacidade de predação foi afetada.(AU)

Lethal and sublethal effects of chlorantraniliprole on Spodoptera cosmioides (Lepidoptera: Noctuidae).

BACKGROUND: The Spodoptera cosmioides (Walker, 1858) population has increased in Bacillus thuringiensis Berliner (Bt) soybean crops in Argentina. As there are no registered products for its control, the recommended insecticides for S. frugiperda are used. The aim of this study was therefore to determine the lethal concentration (LC) of chlorantraniliprole and its sublethal effects on the biological and reproductive functions of S. cosmioides, an emerging soybean pest in Argentina. RESULTS: An ingestion toxicity bioassay showed that chlorantraniliprole was active against larvae of the second instar, and after 48 h of exposure LC50 was 0.054 µg mL-1 H2 O. In the study of sublethal effect, chlorantraniliprole induced changes in the life cycle of exposed S. cosmioides, which required more time to complete all stages of development (larval, pupal and adult stages). Pupal weight was also higher in larvae exposed to sublethal concentrations of chlorantraniliprole. Adult fecundity was decreased: the number of eggs laid by each adult female moth, as compared with control females, was two (LC15 ) and eight (LC30 ) times lower. CONCLUSION: These results indicate that chlorantraniliprole has toxicity against S. cosmioides larvae. Sublethal effects on the biological and reproductive performance of this species can help optimize integrated pest management programs. © 2018 Society of Chemical Industry.

Alternative control of Aedes aegypti resistant to pyrethroids: lethal and sublethal effects of monoterpene bioinsecticides.

BACKGROUND: The mosquito Aedes aegypti is intensively controlled because it is a vector of viruses that cause numerous diseases, especially in tropical regions. As a consequence of the indiscriminate use of insecticides, populations from different regions have become resistant to pyrethroids. Here, we analyzed the lethal and sublethal effects of essential oil of Aristolochia trilobata and its major compounds on A. aegypti from susceptible and pyrethroid-resistant populations. RESULTS: Our results showed that the toxicity of the different compounds and behavioral changes in response to them are dependent on the stage of the insect life cycle. The monoterpene ρ-cymene caused high mortality in both larvae and adult females of A. aegypti, including those from the pyrethroid-resistant population. The monoterpenes limonene and linalool caused a sublethal effect in the larvae, triggering changes in the swimming pattern. CONCLUSION: This study highlights the potential of the essential oil of A. trilobata and its major compounds ρ-cymene and limonene for the control of A. aegypti and reveals the importance of analyzing sublethal effects on the population dynamics of the A. aegypti mosquito. © 2017 Society of Chemical Industry.

Sublethal effect of Abamectin in the functional response of the predator Phytoseiulus persimilis (Athias-Henriot) on Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae)

Abstract The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.

Resumo O controle biológico utilizado para o controle de Tetranychus urticae (Koch) é o acaro predador Phytoseiulus persimilis (Athias-Henriot). É importante conhecer os efeitos dos acaricidas sobre o comportamento biológico do predador. Foi avaliado o efeito tóxico de a Abamectina na resposta funcional de P. persimilis. A resposta funcional do predador foi tipo II exposta a concentrações subletais de Abacmetina, os parâmetros da resposta funcional: taxa de ataque (a'), tempo de manipulação (Th), a eficiência na procura e predação teórica máxima (T/Th) foram afetados pelo acaricida. O predador passa mais tempo na procura, dominar, consumir e se preparar para a próxima procura em comparação com a testemunha e sua capacidade de predação foi afetada.

Relative Toxicity of Two Aphicides to Hippodamia convergens (Coleoptera: Coccinellidae): Implications for Integrated Management of Sugarcane Aphid, Melanaphis sacchari (Hemiptera: Aphididae).

Flupyradifurone and sulfoxaflor present novel insecticide chemistries with particular efficacy against aphids, and the recent emergence of sugarcane aphid, Melanaphis sacchari (Zehntner), as a pest of sorghum in the United States has resulted in their widespread use. We examined their toxicity to Hippodamia convergens Guerin-Meneville, an important aphid biocontrol agent. We exposed beetles to topical applications of the field rate (FR) of these insecticides, fed them contaminated food (eggs of Ephestia kuehniella Zeller), and gave first-instar larvae 24-h exposures to leaf residues. More than half of fourth-instar larvae receiving topical applications of sulfoxaflor at FR survived, whereas flupyradifurone at 0.1× FR caused 90% mortality. Adults survived topical treatments better than larvae and without measurable mortality, except flupyradifurone at FR, which killed more than 80% of beetles. Survivors of all treatments had fertility similar to controls, whether treated as larvae or adults. Ingestion of contaminated food caused significant mortality in all treatments (15-40% for adults and 55-85% for larvae), with no significant differences between insecticides at FR. Leaf residues of sulfoxaflor at 1.0 and 2.0× FR caused approximately 60 and 80% mortality of first instars, respectively, whereas flupyradifurone at 0.1 and 1.0× FR caused > 90% mortality. Although sulfoxaflor was less toxic to H. convergens than flupyradifurone, the tested FR of flupyradifurone has now been reduced by half. We conclude that neither insecticide appears as toxic as other nicotinic acetylcholine receptor agonists, and that both materials are compatible with integrated pest management programs for M. sacchari.

Sublethal effect of Abamectin in the functional response of the predator Phytoseiulus persimilis (Athias-Henriot) on Tetranychus urticae (Koch) (Acari: Phytoseiidae, Tetranychidae)

Abstract The biological control used for the control of Tetranychus urticae (Koch) is the predator mite Phytoseiulus persimilis (Athias-Henriot). It is important to the know the effects of acaricides on the biological behavior the Abamectin on the functional response of P. persimilis. The functional response of the predator was of type II exposed to concentration of Abamectin, the functional response parameters: successful attack rate (a), handling time (Th), search efficiency and the maximum predation theory (T/Th) were affected by the acaricide. The predator spends more time in persecute, dominate, consume and prepair it self to the next searching comparing with the proof subject an the predation ability was affected.

Resumo O controle biológico utilizado para o controle de Tetranychus urticae (Koch) é o acaro predador Phytoseiulus persimilis (Athias-Henriot). É importante conhecer os efeitos dos acaricidas sobre o comportamento biológico do predador. Foi avaliado o efeito tóxico de a Abamectina na resposta funcional de P. persimilis. A resposta funcional do predador foi tipo II exposta a concentrações subletais de Abacmetina, os parâmetros da resposta funcional: taxa de ataque (a'), tempo de manipulação (Th), a eficiência na procura e predação teórica máxima (T/Th) foram afetados pelo acaricida. O predador passa mais tempo na procura, dominar, consumir e se preparar para a próxima procura em comparação com a testemunha e sua capacidade de predação foi afetada.

Enzymatic biomarkers as tools to assess environmental quality: a case study of exposure of the honeybee Apis mellifera to insecticides.

The present study was intended to evaluate the responses of enzymes in the honeybee Apis mellifera after exposure to deltamethrin, fipronil, and spinosad and their use as biomarkers. After determination of the median lethal doses (LD50), honeybees were exposed at doses of 5.07 ng/bee and 2.53 ng/bee for deltamethrin, 0.58 ng/bee and 0.29 ng/bee for fipronil, and 4.71 ng/bee and 2.36 ng/bee for spinosad (equivalent to 1/10th [LD50/10] and 1/20th [LD50/20] of the LD50, respectively). The responses of acetylcholinesterase (AChE), carboxylesterases (CaEs-1-3), glutathione-S-transferase (GST), catalase (CAT), and alkaline phosphatase (ALP) were assessed. The results showed that deltamethrin, fipronil, and spinosad modulated these biomarkers differentially. For the enzyme involved in the defense against oxidative stress, fipronil and spinosad induced CAT activity. For the remaining enzymes, 3 response profiles were identified. First, exposure to deltamethrin induced slight effects and modulated only CaE-1 and CaE-2, with opposite effects. Second, spinosad exhibited an induction profile for most of the biomarkers, except AChE. Third, fipronil did not modulate AChE, CaE-2, or GST, increased CAT and CaE-1, and decreased ALP. Thus, this set of honeybee biomarkers appears to be a promising tool to evaluate environmental and honeybee health, and it could generate fingerprints to characterize exposures to pesticides.