Publications by authors named "Angelica Plata-Rueda"

33 Publications

Susceptibility of Demotispa neivai (Coleoptera: Chrysomelidae) to Beauveria bassiana and Metarhizium anisopliae entomopathogenic fungal isolates.

Pest Manag Sci 2021 Aug 28. Epub 2021 Aug 28.

Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Brazil.

Background: The potential of Beauveria bassiana and Metarhizium anisopliae isolates obtained from naturally infected oil palm pests was evaluated to control Demotispa neivai as an alternative for organophosphate insecticide use in oil palm crops in Latin America. Two B. bassiana (Bb-0018 and Bb-0025) and two M. anisopliae (Ma-0002 and Ma-0003) isolates were tested against D. neivai adults for hydrophobicity, virulence, survival, adhesion to host cuticle, and mortality in semi-field conditions.

Results: Concentration-mortality bioassays demonstrate that isolates had lethal effect on D. neivai adults with Bb-0025 [median lethal concentration (LC ) = 3.45 × 10 conidia mL ] and Bb-0018 (LC  = 3.75 × 10 conidia mL ) being the most effective followed by Ma-0003 (LC  = 3.38 × 10 conidia mL ) and Ma-0002 (5.33 × 10 conidia mL ). Adult survival was 99% without exposure to fungal isolates, decreasing to 21.65% in insects exposed to Ma-0002, 19.41% with Ma-0003, 20.13% with Bb-0018, and 0.17% with Bb-0025. Mortality of D. neivai adults caused by the entomopathogenic fungal isolates was similar in both laboratory and semi-field conditions. Also, vegetative growth of the entomopathogenic fungal isolates was found in infected D. neivai adults in the field.

Conclusion: Our data suggest that the tested entomopathogenic fungal isolates are effective against D. neivai with potential to be used as biological control agents contributing to the decrease of the use of chemical insecticides to control this oil palm pest.
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http://dx.doi.org/10.1002/ps.6613DOI Listing
August 2021

Behavioral and ultrastructural effects of novaluron on Aedes aegypti larvae.

Infect Genet Evol 2021 09 21;93:104974. Epub 2021 Jun 21.

Department of General Biology, Federal University of Viçosa, 36570-000 Viçosa, MG, Brazil. Electronic address:

Chitin synthesis inhibitors (CSI) are supposed to inhibit formation of chitin microfibrils in newly synthesized cuticle during molting process. Conversely, there has been comparatively few data on morphological effects of CSI on non-target insect organs. In this work, the effects of the CSI novaluron on behavior and midgut of A. aegypti were evaluated. Toxicity bioassays revealed that novaluron is toxic to A. aegypti larva with LC = 18.57 mg L when exposed in aqueous solution for 24 h. Novaluron treated larvae were less active and spent more time resting compared to the control group. Histopathology showed that midguts of novaluron-treated larvae had cytoplasm vacuolization and damaged brush border. Cytotoxic effects in midguts of treated larvae induced necrosis, autophagy and damage to mitochondria. Despite being chitin synthesis inhibitor, novaluron did not induce alterations in the integument of A. aegypti larvae. Fluorescence microscopy revealed that the number of digestive cells were higher in novaluron-treated larvae than in control, in response to digestive cell apoptosis. The present study highlights the importance of novaluron against A. aegypti larvae by causing injuries to non-target organs, altering behaviors, inducing cell death and inhibiting cell proliferation.
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http://dx.doi.org/10.1016/j.meegid.2021.104974DOI Listing
September 2021

Exposure to insecticides causes effects on survival, prey consumption, and histological changes in the midgut of the predatory bug, Podisus nigrispinus (Hemiptera: Pentatomidae).

Environ Sci Pollut Res Int 2021 Jun 5. Epub 2021 Jun 5.

Departamento de Entomologia/BIOAGRO, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil.

The control of defoliating caterpillars in forestry includes the use of insecticides and releases of the predatory bug Podisus nigrispinus, but some compounds may affect non-target natural enemies, which need evaluation of risk assessment. This research investigates the survival, preference, and prey consumption of P. nigrispinus adults fed with prey treated with the lethal concentration (LC) of Bacillus thuringiensis (Bt), permethrin, tebufenozide, and thiamethoxam. Moreover, midgut histopathology of P. nigrispinus fed with preys treated with LC of each insecticide was investigated. The insecticides Bt, permethrin, and thiamethoxam reduce the survival and the prey consumption in P. nigrispinus fed with preys contaminate with these chemicals. However, the four tested insecticides, including tebufenozide, cause histological changes such as irregular epithelial architecture, cytoplasm vacuolization, and release of cell fragments in the midgut lumen of P. nigrispinus. The sublethal effects of Bt, permethrin, tebufenozide, and thiamethoxam to the natural enemy suggest that they should be better evaluated to be used together with P. nigrispinus for integrated pest management in forestry.
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http://dx.doi.org/10.1007/s11356-021-14589-9DOI Listing
June 2021

Deltamethrin-Mediated Effects on Locomotion, Respiration, Feeding, and Histological Changes in the Midgut of Caterpillars.

Insects 2021 May 22;12(6). Epub 2021 May 22.

Department of General Biology, Federal University of Viçosa, Viçosa 36570000, Brazil.

(J.E. Smith) (Lepidoptera: Noctuidae) is the main pest of maize crops, and effective methods for pest management are needed. The insecticidal efficacy of deltamethrin was evaluated against for toxicity, survival, locomotion, anti-feeding, and histological changes in the midgut. Concentration-mortality bioassays confirmed that deltamethrin (LC = 3.58 mg mL) is toxic to caterpillars. The survival rate was 99.7% in caterpillars not exposed to deltamethrin, decreasing to 50.3% in caterpillars exposed to LC, and 0.1% in caterpillars treated with LC. demonstrated reduced mobility on deltamethrin-treated surfaces. Deltamethrin promoted a low respiration rate of for up to 3 h after insecticide exposure, displaying immobilization and inhibiting food consumption. Deltamethrin induces histological alterations (e.g., disorganization of the striated border, cytoplasm vacuolization, and cell fragmentation) in the midgut, damaging the digestive cells and peritrophic matrix, affecting digestion and nutrient absorption.
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http://dx.doi.org/10.3390/insects12060483DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8224794PMC
May 2021

The salivary glands of Brontocoris tabidus (Heteroptera: Pentatomidae): Morphology and secretory cycle.

Tissue Cell 2021 Jun 22;70:101498. Epub 2021 Jan 22.

Department of General Biology, Federal University of Viçosa, 36570-900, Viçosa, MG, Brazil. Electronic address:

Brontocoris tabidus (Signoret) (Heteroptera: Pentatomidae) is a zoophytophagous insect used for biological control in agriculture and forest systems because its nymphs and adults feed on insects and plants. The predatory Pentatomidae insert the mouthparts into the prey, releasing saliva to paralysis and kills the insect, as well as digest body parts to be sucked in a preliminary extra-oral digestion. In a short period of time, this insect shows the ability to feed again, suggesting the existence of a constant and abundant secretory cycle in the salivary glands. This study evaluated the morphological, histochemical and ultrastructural changes of the salivary glands of B. tabidus in fed and starved insects. The salivary complex of this predatory bug has a pair of bilobed salivary glands and a pair of tubular accessory salivary glands. The accessory glands have the lumen lined by a thick non-cuticular layer rich in glycoproteins. The secretory cells of the B. tabidus principal salivary glands have constant secretory activity, with each lobe producing different substances. The physiological processes that occur in the salivary gland of B. tabidus indicate that the insect needs to feed constantly, corroborating the potential of this insect to be used in biological control programs.
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http://dx.doi.org/10.1016/j.tice.2021.101498DOI Listing
June 2021

Effect of Benzoylphenyl Ureas on Survival and Reproduction of the Lace Bug, .

Insects 2021 Jan 6;12(1). Epub 2021 Jan 6.

Department of General Biology, Federal University of Viçosa, Viçosa 36570-000, Brazil.

The lace bug, is a vector of fungal complex in oil palm crops in the Americas. The effects of four benzoylphenyl ureas (BPUs) (lufenuron, novaluron, teflubenzuron, and triflumuron) were evaluated against for toxicity, survival, reproduction, and mortality in semi-field conditions. Concentration-mortality bioassays demonstrated that novaluron (LC = 0.33 ppm), teflubenzuron (LC = 0.24 ppm), lufenuron (LC = 0.17 ppm), and triflumuron (LC = 0.42 ppm) are toxic to nymphs. The survival rate was 99% in control nymphs, decreasing to 50% in nymphs exposed to LC of triflumuron, 47% in nymphs treated with lufenuron, 43% in nymphs treated with teflubenzuron, and 43% in those treated with novaluron. Sublethal concentrations of BPUs showed detrimental effects on the adult emergence, longevity, fecundity, and fertility of this insect. The mortality of nymphs caused by these insecticides was similar in both laboratory and semi-field conditions. Our results suggest that novaluron, teflubenzuron, and triflumuron are highly effective against , and therefore, have potential applications for this oil palm pest.
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http://dx.doi.org/10.3390/insects12010034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7824969PMC
January 2021

Exposure to chlorantraniliprole reduces locomotion, respiration, and causes histological changes in the midgut of velvetbean caterpillar Anticarsia gemmatalis (Lepidoptera: Noctuidae).

Chemosphere 2021 Jan 17;263:128008. Epub 2020 Aug 17.

Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil. Electronic address:

The anthranilic diamide, chlorantraniliprole is a systemic insecticide affecting ryanodine receptors. This insecticide is used to control caterpillars in soybean crops because it has low toxicity to non-target organisms. The objective was to identify side-effects of chlorantraniliprole on midgut histopathology, respiration and behavior of the velvetbean caterpillar Anticarsia gemmatalis in laboratoty. Chlorantraniliprole has LC = 0.61 (0.58-0.64) mg mL for A. gemmatalis fourth instar caterpillars after 96 h. The insecticide causes severe histopathological effects in the midgut with epithelial disorganization, microvilli degeneration, cytoplasm vacuolization, cell fragmentation, and peritrophic matrix disorganization. The respiratory rate and the walking speed decrease, whereas the resting period increase for caterpillars exposed to this insecticide. Chlorantraniliprole is toxic to A. gemmatalis at median lethal concentrations causing severe histological and ultrastructural changes with degeneration of the midgut epithelium, reduction of respiratory rates and inducing an arresting behavioral response of this insect.
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http://dx.doi.org/10.1016/j.chemosphere.2020.128008DOI Listing
January 2021

Respiration, predatory behavior and prey consumption by Podisus nigrispinus (Heteroptera: Pentatomidae) nymphs exposed to some insecticides.

Chemosphere 2020 Dec 16;261:127720. Epub 2020 Jul 16.

Departamento de Entomologia/BIOAGRO, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil. Electronic address:

Podisus nigrispinus Dallas (Heteroptera: Pentatomidae) preys on insect pests in eucalyptus plantations where it can be exposed to insecticides used in pest control. The effect of insecticides on non-target natural enemies requires further study. The objective of the present study was to evaluate the side-effects of Bacillus thuringiensis (Bt), permethrin, tebufenozide and thiamethoxam on third instar nymphs of the predator P. nigrispinus in the laboratory. The toxicity of insecticides for this insect was determined by estimating their lethal concentrations. Podisus nigrispinus behavior after exposure to insecticides was analyzed using a video tracking system and the respiratory rate with a respirometer. Prey/nymph consumption was assessed after 24 h of starvation. The preference of P. nigrispinus nymphs, for prey treated or not with the insecticides, was evaluated in free choice tests. The insecticides Bt [LC = 1.10(0.83-1.46) mg mL], permethrin [LC = 0.25(0.17-0.34) mg mL], tebufenozide [LC = 5.71(4.17-7.57) mg mL] and thiamethoxam [LC = 0.04(0.02-0.06) mg mL] are toxic to P. nigrispinus nymphs. Bt and the insecticides tebufenozide, permethrin and thiamethoxam reduced the respiratory rate of P. nigrispinus. The insecticides permethrin, tebufenozide and thiamethoxam affect the locomotion of this insect's nymphs. Prey treated with Bt, permethrin and thiamethoxam are less preferred by P. nigrispinus. The survival of the nymphs of this predator was 93.3%, 66.7%, 56.6%, 0% and 0% in the control, tebufenozide, Bt, permethrin and thiamethoxam treatments, respectively. In addition, the reduction of prey consumption, treated with neurotoxic insecticides, reduces the predatory potential of this natural enemy. Bt and tefubenozide present low toxicity for P. nigrispinus, but the neurotoxic products have low compatibility with this natural enemy and, therefore, are not recommended, with this predator in the management of forest insect pests.
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http://dx.doi.org/10.1016/j.chemosphere.2020.127720DOI Listing
December 2020

Acute Toxicity and Sublethal Effects of Lemongrass Essential Oil and Their Components against the Granary Weevil, .

Insects 2020 Jun 18;11(6). Epub 2020 Jun 18.

Department of General Biology, Federal University of Viçosa, Viçosa, MG 36570-000, Brazil.

In the present work, we evaluate the toxic and repellent properties of lemongrass ( (DC. ex Nees) Stapf.) essential oil and its components against Linnaeus as an alternative to insecticide use. The lethal dose (LD and LD), survivorship, respiration rate, and repellency on adults of exposed to different doses of lemongrass oil and some of its components were evaluated. The chemical composition of the essential oil was found to have the major components of neral (24.6%), citral (18.7%), geranyl acetate (12.4%), geranial (12.3%), and limonene (7.55%). Lemongrass essential oil (LD = 4.03 µg·insect), citral (LD = 6.92 µg·insect), and geranyl acetate (LD = 3.93 µg·insect) were toxic to adults. Survivorship was 99.9% in insects not exposed to lemongrass essential oil, decreasing to 57.6%, 43.1%, and 25.9% in insects exposed to LD of essential oil, citral, and geranyl acetate, respectively. The insects had low respiratory rates and locomotion after exposure to the essential oil, geranyl acetate, and citral. Our data show that lemongrass essential oils and their components have insecticidal and repellent activity against and, therefore, have the potential for application in stored grain pest management schemes.
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http://dx.doi.org/10.3390/insects11060379DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7349354PMC
June 2020

Insecticidal Activity of Strains on the Nettle Caterpillar, (Lepidoptera: Limacodidae).

Insects 2020 May 15;11(5). Epub 2020 May 15.

Department of General Biology, Federal University of Viçosa, Viçosa, Minas Gerais 36570-000, Brazil.

In the present work, we evaluated the insecticidal activity of () strains on as an alternative for the organophosphate insecticide use in oil palm plantations in the Americas. The toxic effects of four -strains (HD-1 var. , SA-12 var. , ABTS-1857 var. , and GC-91 var. ) were evaluated against caterpillars for toxicity, survival, anti-feeding, and mortality in field-controlled conditions. The -strains, ABTS-1857 var. (LC = 0.84 mg mL), GC-91 var. (LC = 1.13 mg mL), and HD-1 var. (LC = 1.25 mg mL), were the most toxic to . The caterpillar survival was 99% without exposure to -strains, and decreased to 52-23% in insects treated with the LC and 10-1% in insects exposed to LC after 48 h. Furthermore, -strains decreased significantly the consumption of oil palm leaves of 3 h after exposure. Mortality of caterpillars caused by -strains had similar lethal effects in the laboratory and in field conditions. Our data suggest that -strains have insecticidal activity against and, therefore, have potential applications in oil palm pest management schemes.
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http://dx.doi.org/10.3390/insects11050310DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7290276PMC
May 2020

Side effects of Bacillus thuringiensis on the parasitoid Palmistichus elaeisis (Hymenoptera: Eulophidae).

Ecotoxicol Environ Saf 2020 Feb 21;189:109978. Epub 2019 Nov 21.

Departamento de Entomologia, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais, Brazil.

The endoparasitoid wasp Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) is used to control defoliating lepidopteran pests. Chemical insecticides are not compatible with natural enemies, but bioinsecticides, such as Bacillus thuringiensis Berliner (Bt), have great potential for use in integrated pest management. However, interactions between Bt and P. elaeisis still need to be investigated. This study aimed to evaluate the effects of Bt on parental and first-generation P. elaeisis parasitizing Bt-susceptible and -resistant Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). An additional aim was to determine the toxicity of Bt to susceptible third-instar S. frugiperda larvae. Larvae were exposed to lethal concentrations (LC and LC) of Bt and then allowed to be parasitized by P. elaeisis. Parasitoid longevity, immature production, reproductive performance, and behavioral responses were evaluated. Bt repelled P. elaeisis and reduced immature production. Parental and first filial generation parasitoids of both sexes emerged from Bt-treated larvae showed lower survivorship than controls. Parasitoids had poorer reproductive performance in Bt-susceptible and -resistant pupae than in untreated pupae. Palmistichus elaeisis emerged from Bt-susceptible and -resistant S. frugiperda showed altered host-searching behavior and reproductive parameters, which indicates low compatibility between the bioinsecticide agent and the parasitoid wasp.
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http://dx.doi.org/10.1016/j.ecoenv.2019.109978DOI Listing
February 2020

Pyriproxyfen, a juvenile hormone analog, damages midgut cells and interferes with behaviors of larvae.

PeerJ 2019 4;7:e7489. Epub 2019 Sep 4.

Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil.

Juvenile hormone analogs (JHA) are known to interfere with growth and biosynthesis of insects with potential for insecticide action. However, there has been comparatively few data on morphological effects of JHA on insect organs. To determine pyriproxyfen effects on larvae, we conducted toxicity, behavioral bioassays and assessed ultrastructural effects of pyriproxyfen on midgut cells. larvae were exposed in aqueous solution of pyriproxyfen LC concentrations and evaluated for 24 h. This study fulfilled the toxic prevalence of pyriproxyfen to larvae (LC = 8.2 mg L). Behavioral observations confirmed that pyriproxyfen treatment significantly changes swimming behavior of larvae, limiting its displacement and speed. The pyriproxyfen causes remarkable histopathological and cytotoxic alterations in the midgut of larvae. Histopathological study reveals presence of cytoplasmic vacuolization and damage to brush border of the digestive cells. The main salient lesions of cytotoxic effects are occurrence of cell debris released into the midgut lumen, cytoplasm rich in lipid droplets, autophagosomes, disorganized microvilli and deformed mitochondria. Data suggest that pyriproxyfen can be used to help to control and eradicate this insect vector.
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http://dx.doi.org/10.7717/peerj.7489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6731771PMC
September 2019

Histopathological and cytotoxic changes induced by spinosad on midgut cells of the non-target predator Podisus nigrispinus Dallas (Heteroptera: Pentatomidae).

Chemosphere 2020 Jan 19;238:124585. Epub 2019 Aug 19.

Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais, Brazil. Electronic address:

Broad-spectrum insecticides used in pest control are a risk for non-target insects. Their compatibility to the insecticide spinosad, used in agriculture and forestry as a biological control tool, needs to be evaluated. Podisus nigrispinus Dallas (Heteroptera: Pentatomidae) is a predatory bug used in the pest management of agricultural and forest systems where spinosad is also frequently applied. The aim of this study was to evaluate the toxicity, histopathology and cytotoxicity in midgut cells of P. nigrispinus exposed to spinosad. The toxicity test was performed to determine the lethal concentrations of spinosad after exposure by ingestion. The histopathology and cytotoxicity caused by spinosad were analyzed in the three midgut regions (anterior, middle and posterior) of P. nigrispinus during different exposure periods. Spinosad, at low concentrations, was toxic to P. nigrispinus [LC = 3.15 (3.02-3.26) μg.L]. Cell degeneration features such as cytoplasm vacuolization, chromatin condensation and release of cell fragments to the midgut lumen were observed in this organ. Cell death via apoptosis was found in the three midgut regions of this predator after exposure to the insecticide. Spinosad is toxic to P. nigrispinus, and causes histological and cytological damage followed by cell death in the midgut, suggesting a dangerous effect on a beneficial non-target insect.
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http://dx.doi.org/10.1016/j.chemosphere.2019.124585DOI Listing
January 2020

Bioactivity of the Cymbopogon citratus (Poaceae) essential oil and its terpenoid constituents on the predatory bug, Podisus nigrispinus (Heteroptera: Pentatomidae).

Sci Rep 2019 06 7;9(1):8358. Epub 2019 Jun 7.

Departamento de Entomologia/BIOAGRO, Universidade Federal de Viçosa, 36.570-900, Viçosa, Minas Gerais, Brazil.

Podisus nigrispinus Dallas (Heteroptera: Pentatomidae), released in biological control programs, is a predator of Lepidopteran and Coleopteran species. Lemongrass essential oil and its constituents can be toxic to this natural enemy. The major constituents of lemongrass essential oil are neral (31.5%), citral (26.1%), and geranyl acetate (2.27%). Six concentrations of lemongrass essential oil and of its citral and geranyl acetate constituents were applied to the thorax of P. nigrispinus nymphs and adults. The walking and respiratory behavior of the P. nigrispinus third-instar nymphs, treated with citral and geranyl acetate at the LD and LD doses, were analyzed with video and respirometer. The lemongrass essential oil toxicity increased from first- to fifth-instar P. nigrispinus nymphs. The P. nigrispinus respiration rates (μL de CO h/insect) with citral and geranyl acetate in the LD and LD differed. Nymphs exposed to the lemongrass essential oil and its constituents on treated surfaces presented irritability or were repelled. Podisus nigrispinus adults were tolerant to the lemongrass essential oil and its constituents, geranyl acetate and citral. The altered respiratory activity with geranyl acetate and the fact that they were irritated and repelled by citral suggest caution with regard to the use of the lemongrass essential oil and its constituents in integrated pest management incorporating this predator, in order to avoid diminishing its efficiency against the pests.
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http://dx.doi.org/10.1038/s41598-019-44709-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555811PMC
June 2019

Chlorantraniliprole degenerates microvilli goblet cells of the Anticarsia gemmatalis (Lepidoptera: Noctuidae) midgut.

Chemosphere 2019 Aug 6;229:525-528. Epub 2019 May 6.

Departamento de Entomologia/BIOAGRO, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-900, Brazil.

Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) is mainly controlled with synthetic insecticides such as chlorantraniliprole. However, these compounds may affect non-target organs of insect metabolism. The objective of this study was to evaluate the toxic effect in the midgut goblet cells of A. gemmatalis caterpillars exposed to chlorantraniliprole. The midgut of these caterpillars, which ingested the insecticide in medium-lethal dose (LD), was dissected and evaluated by transmission electron microscopy. The goblet cells microvilli, after exposure to the insecticide, were disorganized and degenerated. This can compromise ionic homeostasis and nutrient absorption, impair physiological mechanisms of detoxification, and reduce the movement of food boluses throughout the insect midgut.
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http://dx.doi.org/10.1016/j.chemosphere.2019.05.041DOI Listing
August 2019

Exposure to Insecticides Reduces Populations of in Oil Palm Plantations with Bud Rot Disease.

Insects 2019 Apr 19;10(4). Epub 2019 Apr 19.

Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa 36570-000, Minas Gerais, Brazil.

The South American palm weevil (SAPW), Linnaeus (Coleoptera: Curculionidae) is the main pest of and damages palm trees with bud rot disease in the Americas. The effects of six neurotoxic insecticides (abamectin, carbaryl, deltamethrin, fipronil, imidacloprid and spinosad) were evaluated against SAPW for toxicity, survival, reproduction, and mortality. Abamectin (LC = 0.33 mg mL), Carbaryl (LC = 0.24 mg mL), deltamethrin (LC = 0.17 mg mL), and fipronil (LC = 0.42 mg mL) were the most toxic to SAPW. Adult survival was 95% without exposure to insecticides, decreasing to 78-65% in insects treated with the LC and 49-35% in insects exposed to LC. Sublethal doses of carbaryl, fipronil and imidacloprid showed significant effect on the reproduction of this insect. Mortality of SAPW populations caused by insecticides had similar effects in the laboratory and field conditions. The results suggest that carbaryl, deltamethrin, fipronil, and imidacloprid caused significantly higher mortality as compared to the control in SAPW and may be used to control its populations in oil palm trees where bud rot appears as the key disease for SAPW attraction and infestation.
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http://dx.doi.org/10.3390/insects10040111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523913PMC
April 2019

Exposure to spinosad induces histopathological and cytotoxic effects on the salivary complex of the non-target predator Podisus nigrispinus.

Chemosphere 2019 Jun 15;225:688-695. Epub 2019 Mar 15.

Instituto de Ciências Agrárias, Universidade Federal de Viçosa, 38810-000, Rio Paranaíba, Minas Gerais, Brazil. Electronic address:

In integrated pest management systems, biological and chemical controls must be compatible. The insecticide spinosad affects some non-target insects and might compromise their fitness. The objective of this study was to evaluate the histopathological and cytotoxic effects of spinosad on the salivary complex of the predatory bug Podisus nigrispinus (Heteroptera: Pentatomidae). Spinosad toxicity and insect survival were determined using six concentrations of insecticide. Ultrastructural changes and cell death of salivary glands were analyzed after P. nigrispinus exposure to spinosad LC (3.15 μg L). The insecticide caused toxicity to P. nigrispinus; survival was 32% after 48 h of exposure to LC. The main histological changes in the salivary complex were disorganization of the epithelium, cytoplasmic vacuolization, and apocrine secretion into the gland lumen. Cytotoxic effects, such as release of granules and vacuoles into the lumen, presence of autophagosomes, enlargement of basal plasma membrane infoldings, and apoptosis, were observed. Spinosad causes toxicity, decreases survival, and changes the histology and cytology of the P. nigrispinus salivary complex. The results suggest that the cellular stress induced by the insecticide affects extra-oral digestion, compromising the potential of P. nigrispinus as a biological pest control agent.
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http://dx.doi.org/10.1016/j.chemosphere.2019.03.105DOI Listing
June 2019

Chlorantraniliprole-mediated effects on survival, walking abilities, and respiration in the coffee berry borer, Hypothenemus hampei.

Ecotoxicol Environ Saf 2019 May 22;172:53-58. Epub 2019 Jan 22.

Instituto de Ciências Agrárias, Universidade Federal de Viçosa, 38810-000 Rio Paranaíba, Minas Gerais, Brazil. Electronic address:

Hypothenemus hampei Ferrari (Coleoptera: Curculionidae) is the main pest of coffee crops, and effective methods for pest management are needed urgently. Bioassays were conducted to assess the effects of the insecticide chlorantraniliprole on H. hampei adults. Toxicity, survivorship, larval production, respiration rate, and behavioral responses to six concentrations of chlorantraniliprole were evaluated. Chlorantraniliprole was toxic to H. hampei (LD = 0.49 mg mL and LD = 1.21 mg mL). Survivorship was 98% in adults not exposed to chlorantraniliprole, decreasing to 52% in insects exposed to LD and 2% in insects treated with LD. H. hampei showed reduced mobility on insecticide-treated surfaces. The insecticide promoted a decrease in the respiration rate of H. hampei for up to 3 h after exposure, altering behavioral responses and locomotor activity. Chlorantraniliprole was shown to have lethal and sublethal effects on H. hampei and, thus, can be used rotationally in integrated pest management programs to control of this pest in coffee crops and retard of insect resistance.
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http://dx.doi.org/10.1016/j.ecoenv.2019.01.063DOI Listing
May 2019

Exposure to cyantraniliprole causes mortality and disturbs behavioral and respiratory responses in the coffee berry borer (Hypothenemus hampei).

Pest Manag Sci 2019 Aug 15;75(8):2236-2241. Epub 2019 Mar 15.

Instituto de Ciências Agrárias, Universidade Federal de Viçosa, Rio Paranaíba, Minas Gerais, Brazil.

Background: Hypothenemus hampei Ferrari (Coleoptera: Curculionidae) is the main pest of coffee due to the damage caused to coffee berries. Effective management methods and prevention of insecticide resistance are urgently needed against this insect. Bioassays were conducted to assess the effects of the diamide insecticide cyantraniliprole on H. hampei. Cyantraniliprole is the most recent compound registered against this species after the phasing out of endosulfan, the main insecticide historically used against the coffee borer for the past 30 years. Toxicity, survival, progeny production, respiration rate, and behavioral responses to cyantraniliprole were evaluated.

Results: Cyantraniliprole was toxic to adult H. hampei (LC  = 0.67 mg mL and LC  = 1.71 mg mL ). Adult survival was 95% without exposure to cyantraniliprole, decreasing to 52% in insects exposed to LC cyantraniliprole and 27% in insects treated with LC cyantraniliprole. Furthermore, H. hampei showed reduced mobility on insecticide-treated surfaces. The insecticide also led to a decrease in the respiration rate of H. hampei for up to 3 h after exposure, altering behavioral responses and locomotor activity.

Conclusion: Cyantraniliprole exhibits lethal and sublethal effects on H. hampei and can be used in rotation in integrated pest management programs for control of this species in coffee cultivation systems. © 2019 Society of Chemical Industry.
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http://dx.doi.org/10.1002/ps.5358DOI Listing
August 2019

Toxicity and cytotoxicity of the insecticide imidacloprid in the midgut of the predatory bug, Podisus nigrispinus.

Ecotoxicol Environ Saf 2019 Jan 5;167:69-75. Epub 2018 Oct 5.

Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000 Viçosa, Minas Gerais, Brazil. Electronic address:

The selectivity of insecticides on natural enemies in pest control are an important strategy for Integrated Pest Management. However, insecticides can have side effects on non-target organisms such as natural enemies. This study evaluated the histological and cytological changes mediated by the sublethal concentration of the imidacloprid insecticide on the midgut of non-target predator Podisus nigrispinus (Heteroptera: Pentatomidae), used in the biological control of pests. Imidacloprid was toxic for P. nigrispinus with LC = 3.75 mg L and survival of 51.8%. This sublethal concentration of imidacloprid causes histological alterations in the midgut epithelium and cytotoxic features were irregular border epithelium, cytoplasmic vacuolation, and apocrine secretions in the first 6 h after exposure with the insecticide. Apoptosis in the digestive cells occurs after 12 h of exposure in the midgut. These results suggest that imidacloprid may affect the digestive physiology of P. nigrispinus and compromise the effective predation of this insect a biological control agent. The associated use of this insecticide with the predator in pest control should be carefully evaluated.
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http://dx.doi.org/10.1016/j.ecoenv.2018.09.124DOI Listing
January 2019

Permethrin induces histological and cytological changes in the midgut of the predatory bug, Podisus nigrispinus.

Chemosphere 2018 Dec 27;212:629-637. Epub 2018 Aug 27.

Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais, Brazil. Electronic address:

Insecticides used in the agriculture and forestry have side effects on non-target organisms used as natural enemies. This study evaluated the histopathology and cytotoxicity of permethrin on the midgut of the non-target predatory bug, Podisus nigrispinus (Heteroptera: Pentatomidae) used in the biological control of pest insects. The toxicity and survival of this insect were determined using six concentrations of permethrin via ingestion. Histological and ultraestutural changes of the midgut of P. nigrispinus were analyzed after exposure to permethrin. The insecticide caused toxicity in P. nigrispinus with LC = 0.46 μg L and survival of 47% after 72 h of exposure. The histological changes in the midgut were irregularly bordered epithelium, cytoplasmic vacuolization and apocrine secretions in the lumen after 6 h following exposure to the insecticide. Cytotoxic effects such as granules and vacuoles secreted into the lumen, presence of autophagosomes, and dilatation of infolds of the basal plasma membrane were observed in the three regions of the midgut. Cells of the midgut in apoptosis occurred after 12 h of exposure. Permethrin causes toxic effects, inhibits survival, and produces changes in the histology and cytology of the midgut in P. nigrispinus, suggesting that the cell stress induced by this insecticide can disrupt physiological processes such as digestion, compromising the potential of the predator as a biological control agent of pests. The low selectivity of permethrin to a non-target organism such as the predatory bug, P. nigrispinus indicates that the associated use of this insecticide in biological control should be better evaluated.
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http://dx.doi.org/10.1016/j.chemosphere.2018.08.134DOI Listing
December 2018

Toxicological and morphological effects of tebufenozide on Anticarsia gemmatalis (Lepidoptera: Noctuidae) larvae.

Chemosphere 2018 Dec 20;212:337-345. Epub 2018 Aug 20.

Department of General Biology, Federal University of Viçosa, 36570-000, Viçosa, MG, Brazil. Electronic address:

The velvetbean caterpillar, Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae), is an important soybean pest in the Americas. Tebufenozide, a novel nonsteroidal ecdysone agonist is used to control this pest. Bioassays were conducted to assess tebufenozide toxicity and their ultrastructural effects on midgut of A. gemmatalis. The toxicity, survivorship, behavior response, and respiration rate for A. gemmatalis larvae after exposure to tebufenozide were evaluated. Also, A. gemmatalis larvae were treated with LC obtained from tebufenozide and changes were observed on their midgut cells after 24, 48 and 96 h. Tebufenozide was toxic to A. gemmatalis (LC = 3.86 mg mL and LC = 12.16 mg mL) and survivorship was 95% for adults that had not been exposed to tebufenozide, decreasing to 52% with LC and 27% with LC estimated value. Damage to midgut cells was increased with exposure time. These cells show damaged striated border with release of protrusions to the midgut lumen, damaged nuclear membrane and nucleus with condensed chromatin and increase in amount of autophagic vacuoles. Mitochondria were modified into nanotunnels which might be an evidence that tebufenozide induces damage to cells, resulting in cell death, proved by immunofluorescence analyses. This insecticide also caused paralysis movement with change in homeostasis and compromised larval respiration. Thus, sublethal exposure to tebufenozide is sufficient to disturb the ultrastructure of A. gemmatalis midgut, which might compromise insect fitness, confirming tebufenozide a possible controlling insecticide.
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http://dx.doi.org/10.1016/j.chemosphere.2018.08.088DOI Listing
December 2018

Morphology, ultrastructure, and chemical compounds of the osmeterium of Heraclides thoas (Lepidoptera: Papilionidae).

Protoplasma 2018 Nov 11;255(6):1693-1702. Epub 2018 May 11.

Departamento de Biologia Geral, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs, Campus Universitário Viçosa, Minas Gerais, 36570-000, Brazil.

The osmeterium, found in papilionoid larvae, is an eversible organ with an exocrine gland that produces substances in response to the mechanical disturbances caused by natural enemies. The anatomy, histology and ultrastructure of the osmeterium, and the chemical composition of its secretion in Heraclides thoas (Lepidoptera: Papilionidae) were studied. Heraclides thoas larvae have a Y-shaped osmeterium in the thorax. The surface of the osmeterium has a rough cuticle lining cells with papillae and irregular folds, whereas the cells that limited the gland pores are irregular, folded, and devoid of papillae. Two types of cells are found: (i) cuticular epidermal cells on the surface of the tubular arms of the osmeterium and (ii) secretory cells of the ellipsoid gland within the region of the glandular pore. Cuticular epidermal cells show a thick cuticle, with several layers divided into epicuticle and lamellar endocuticle. Secretory cells are polygonal, with extensive folds in the basal plasma membrane that formed extracellular channels. The cytoplasm has mitochondria, ribosomes, and numerous vacuoles, whereas the nucleus is irregular in shape with decondensed chromatin. The chemical composition of the osmeterial secretion comprised (Z)-α-bisabolene (25.4%), α-bisabol (20.6%), β-bisabolene (13.1%), (E)-α-bisabolene 8%), β-pinene (9.91%), longipinene epoxide (8.92%), (Z)-β-farnesene (6.96%), β-caryophyllene (2.05%), farnesol (1.86%), linalyl propionate (1.86%), and 1-octyn-4-ol (1.07%). The morphological features suggest that the cuticular epidermal cells play a major role in the maintenance and protection of the osmeterium, whereas secretory cells are responsible for production of osmeterial secretions.
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http://dx.doi.org/10.1007/s00709-018-1261-xDOI Listing
November 2018

Terpenoid constituents of cinnamon and clove essential oils cause toxic effects and behavior repellency response on granary weevil, Sitophilus granarius.

Ecotoxicol Environ Saf 2018 Jul 20;156:263-270. Epub 2018 Mar 20.

Departamento de Entomologia, Universidade Federal de Viçosa, 36570-000 Viçosa, Minas Gerais, Brasil. Electronic address:

This study evaluated toxic effects, repellency and respiration rate caused by terpenoid constituents of cinnamon and clove essential oils and against Sitophilus granarius L. (Coleoptera: Curculionidae). The lethal concentrations (LC and LC), repellent effect, and behavior repellency response on adults of S. granarius after exposure to six concentrations of each essential oil and terpenoids were evaluated. The chemical composition of the cinnamon oil was also determined and primary compounds were eugenol (10.5%), trans-3-caren-2-ol (10.2%), benzyl benzoate (9.99%), caryophyllene (9.34%), eugenyl acetate (7.71%), α-phellandrene (7.41%), and α-pinene (7.14%). In clove essential oil, the primary compounds were eugenol (27.1%), caryophyllene (24.5%), caryophyllene oxide (18.3%), 2-propenoic acid (12.2%), α-humulene (10.8%), γ-cadinene (5.01%), and humulene oxide (4.84%). Cinnamon and clove essential oil was toxic to S. granarius. In toxic terpenoids compounds, eugenol has stronger contact toxicity in S. granarius than caryophyllene oxide, followed by α-pinene, α-humulene, and α-phellandrene. Insects reduced their respiratory rates after being exposed to essential oil terpenoids and avoided or reduced their mobility on terpenoid-treated surfaces. Cinnamon and clove essential oil, and their terpenoid constituents were toxic and repellent to adult S. granarius and, therefore, have the potential to prevent or retard the development of insecticide resistance.
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http://dx.doi.org/10.1016/j.ecoenv.2018.03.033DOI Listing
July 2018

Squamocin induce histological and ultrastructural changes in the midgut cells of Anticarsia gemmatalis (Lepidoptera: Noctuidae).

Ecotoxicol Environ Saf 2018 Jul 7;156:1-8. Epub 2018 Mar 7.

Department of General Biology, Federal University of Viçosa, 36570-000 Viçosa, MG, Brazil. Electronic address:

Annonaceous acetogenins (Annona squamosa Linnaeus) comprises of a series of natural products which are extracted from Annonaceae species, squamocin proved to be highly efficient among those agents. Squamocin is mostly referred as a lethal agent for midgut cells of different insects, with toxic effects when tested against larva of some insects. In present study, LC and LC of squamocin for A. gemmatalis Hübner (Lepidoptera: Noctuidae) were calculated using probit analysis. Morphological changes in midgut cells were analyzed under light, fluorescence and transmission electron microscopes when larvae were treated with LC and LC of squamocin for 24, 48 and 72 h. Results revealed that the maximum damage to midgut cells was found under LC where it showed digestive cells with enlarged basal labyrinth, highly vacuolated cytoplasm, damaged apical surface, cell protrusions to the gut lumen, autophagy and cell death. The midgut goblet cells showed a strong disorganization of their microvilli. Likewise, in insects treated with squamocin, mitochondria were not marked with Mitotracker fluorescent probe, suggesting some molecular damage in these organelles, which was reinforced by decrease in the respiration rate in these insects. These results demonstrate that squamocin has potential to induce enough morphological changes in midgut through epithelial cell damage in A. gemmatalis.
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http://dx.doi.org/10.1016/j.ecoenv.2018.02.080DOI Listing
July 2018

Dispersion of the soybean root rot by Cycloneda sanguinea (Coleoptera: Coccinellidae).

Sci Rep 2018 02 5;8(1):2409. Epub 2018 Feb 5.

Departamento de Entomologia/BIOAGRO, Universidade Federal de Viçosa, Viçosa, 36570-900, Brazil.

The dispersion of pathogenic microorganisms consists of the transport of pathogens from their source to inoculate a new host. Agricultural and economic importance of the Soybean root rot justifies studying this disease, especially the role of insects as dispersers. The aim of this study was to evaluate the role of the ladybird beetle, Cycloneda sanguinea Linnaeus (Coleoptera: Coccinellidae) in the dispersion of pathogens that cause Soybean root rot. Three pathogen species, Macrophomina phaseolina (Tassi) (Sphaeropsidales: Botryosphaeriaceae), Fusarium incarnatum-equiseti species complex (FIESC), and F. commune (Skovgaard) O'Donnell & Nirenberg were isolated from the midgut of ladybird beetles and cultured. Macrophomina phaseolina was identified by morphology while for the other two species, DNA was sequenced. The DNA extracted was amplified in the Internal Transcriber Spacer (ITS) region, sequenced and compared to voucher sequences deposited in the GenBank. Sequences of nucleotide ITS1-5.8 S were identified in the regions of rDNA-ITS4 ribosomal DNA. This is the first report of Macrophomina phaseolina (Tassi) (Sphaeropsidales: Botryosphaeriaceae), Fusarium incarnatum-equiseti species complex (FIESC), and F. commune (Skovgaard) O'Donnell & Nirenberg, being dispersed by C. sanguinea in Brazilian soybean fields.
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http://dx.doi.org/10.1038/s41598-018-20587-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5799320PMC
February 2018

Lasioderma serricorne (Coleoptera: Anobiidae): First Report on Black Sesame (Sesamum indicum).

J Food Prot 2017 Oct 20:1941-1943. Epub 2017 Oct 20.

5 Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-900 Viçosa, Minas Gerais, Brasil.

Insect pests may make food products and by-products unfit for human consumption. This study reports the occurrence of Lasioderma serricorne (Coleoptera: Anobiidae) in packaged seeds of black Sesamum indicum. An intact plastic pot of S. indicum seeds was purchased by a consumer in a supermarket in Divinópolis, Minas Gerais state, Brazil, in April 2014 and was kept at his home for 3 months. Two hundred adults of this insect (196 dead and 4 alive) were counted in the pot with the seeds, besides three live larvae. This insect fed on S. indicum seeds, making them unfit for consumption. L. serricorne feed on and reproduce in S. indicum seeds stored in plastic packaging.
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http://dx.doi.org/10.4315/0362-028X.JFP-16-476DOI Listing
October 2017

Insecticidal activity of garlic essential oil and their constituents against the mealworm beetle, Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae).

Sci Rep 2017 04 20;7:46406. Epub 2017 Apr 20.

Departamento de Entomologia, Universidade Federal de Viçosa, 36570-000, Viçosa, Minas Gerais, Brasil.

This study evaluated the insecticidal activity of garlic, Allium sativum Linnaeus (Amaryllidaceae) essential oil and their principal constituents on Tenebrio molitor. Garlic essential oil, diallyl disulfide, and diallyl sulfide oil were used to compare the lethal and repellent effects on larvae, pupae and adults of T. molitor. Six concentrations of garlic essential oil and their principal constituents were topically applied onto larvae, pupae and adults of this insect. Repellent effect and respiration rate of each constituent was evaluated. The chemical composition of garlic essential oil was also determined and primary compounds were dimethyl trisulfide (19.86%), diallyl disulfide (18.62%), diallyl sulfide (12.67%), diallyl tetrasulfide (11.34%), and 3-vinyl-[4H]-1,2-dithiin (10.11%). Garlic essential oil was toxic to T. molitor larva, followed by pupa and adult. In toxic compounds, diallyl disulfide was the most toxic than diallyl sulfide for pupa > larva > adult respectively and showing lethal effects at different time points. Garlic essential oil, diallyl disulfide and diallyl sulfide induced symptoms of intoxication and necrosis in larva, pupa, and adult of T. molitor between 20-40 h after exposure. Garlic essential oil and their compounds caused lethal and sublethal effects on T. molitor and, therefore, have the potential for pest control.
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http://dx.doi.org/10.1038/srep46406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5397855PMC
April 2017

Comparative morphology of the odoriferous system in three predatory stink bugs (Heteroptera: Asopinae).

Protoplasma 2017 Sep 25;254(5):1965-1972. Epub 2017 Feb 25.

Departamento de Biologia Geral, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs, Campus Universitário Viçosa, Minas Gerais, 36570-000, Brazil.

The metathoracic scent system in Heteroptera produces and releases defensive volatile compounds. The odor produced by predatory stink bugs differs from phytophagous bugs, suggesting a variation between the structure and function of the metathoracic scent system. The anatomy and ultrastructure of the external thoracic efferent system, scent gland, and reservoir in the stink bug predators Brontocoris tabidus, Podisus nigrispinus, and Supputius cincticeps (Heteroptera: Pentatomidae: Asopinae) were studied. External thoracic efferent systems of B. tabidus, P. nigrispinus, and S. cincticeps have anatomical differences in ostiole, peritreme, and evaporatorium. Scent glands have a secretory portion and a reservoir. The reservoir has irregular projections, and in B. tabidus, it is enlarged and heart shaped, whereas in P. nigrispinus and S. cincticeps it is flattened and semicircular. The secretory tissue of the scent gland has well-developed globular secretory cells that produce odorous compounds, and the reservoir has a single layer of cubical cells lined by a cuticular intima. Secretory cells are type III with an intracellular end apparatus, well-developed nucleus with decondensed chromatin, and cytoplasm rich in mitochondria, lysosomes, granules, and smooth endoplasmic reticulum. These findings suggest that there are differences in physiological function of the odoriferous system and the volatile compounds produced by the secretory cells, which may indicate variation in defensive behavior of these species.
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http://dx.doi.org/10.1007/s00709-017-1087-yDOI Listing
September 2017

Toxic effects of the neem oil (Azadirachta indica) formulation on the stink bug predator, Podisus nigrispinus (Heteroptera: Pentatomidae).

Sci Rep 2016 09 6;6:30261. Epub 2016 Sep 6.

Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais, Brasil.

This research investigated the effects of neem oil on mortality, survival and malformations of the non-target stink bug predator, Podisus nigrispinus. Neurotoxic and growth inhibitor insecticides were used to compare the lethal and sublethal effects from neem oil on this predator. Six concentrations of neem oil were topically applied onto nymphs and adults of this predator. The mortality rates of third, fourth, and fifth instar nymphs increased with increasing neem oil concentrations, suggesting low toxicity to P. nigrispinus nymphs. Mortality of adults was low, but with sublethal effects of neem products on this predator. The developmental rate of P. nigrispinus decreased with increasing neem oil concentrations. Longevity of fourth instar nymphs varied from 3.74 to 3.05 d, fifth instar from 5.94 to 4.07 d and adult from 16.5 and 15.7 d with 0.5 and 50% neem doses. Podisus nigrispinus presented malformations and increase with neem oil concentrations. The main malformations occur in wings, scutellum and legs of this predator. The neem oil at high and sub lethal doses cause mortality, inhibits growth and survival and results in anomalies on wings and legs of the non-traget predator P. nigrispinus indicating that its use associated with biological control should be carefully evaluated.
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http://dx.doi.org/10.1038/srep30261DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5011654PMC
September 2016
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