Synergistic Effect Of Piperonyl Butoxide Research Articles

Sublethal effect and detoxifying metabolism of metaflumizone and indoxacarb on the fall armyworm, Spodoptera frugiperda

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera, Noctuidae), is a highly polyphagous invasive pest that damages various crops. Pesticide control is the most common and effective strategy to control FAW. In this study, we evaluated the toxicity of metaflumizone and indoxacarb against third-instar FAW larvae using the insecticide-incorporated artificial diet method under laboratory conditions. Both metaflumizone and indoxacarb exhibited substantial toxicity against FAW, with LC50 values of 2.43 and 14.66 mg/L at 72 h, respectively. The sublethal effects of metaflumizone and indoxacarb on parental and F1 generation FAW were investigated by exposing third-instar larvae to LC10 and LC30 concentrations of these insecticides. Sublethal exposure to these two insecticides significantly shortened adult longevity, extended pupal developmental times and led to reduced pupal weight, pupation rates, and adult fecundity in the treated parental generation and F1 generation at LC10 or LC30 concentrations, in comparison to the control group. The larval developmental times were shortened in the parental generation but prolonged in the F1 generation, after being treated with sublethal concentrations of metaflumizone. Furthermore, larvae exposed to LC10 or LC30 concentrations of indoxacarb exhibited elevated activity levels of cytochrome P450 monooxygenase and glutathione S-transferase, which coincides with the observed synergistic effect of piperonyl butoxide and diethyl maleate. In conclusion, the high toxicity and negative impact of metaflumizone and indoxacarb on FAW provided significant implications for the rational utilization of insecticides against this pest.

ALS gene overexpression and enhanced metabolism conferring Digitaria sanguinalis resistance to nicosulfuron in China.

Crabgrass (Digitaria sanguinalis) is a common malignant weed in corn fields in China. Recently, the acetolactate synthase (ALS) inhibitor, nicosulfuron, has shown decreasing efficacy against crabgrass. In order to elucidate the molecular basis of resistance to nicosulfuron in crabgrass, we conducted bioassays, combined with gene sequence analysis, relative expression and relative copy number analysis, to characterize resistance in crabgrass populations collected from Beijing, Heilongjiang, Jilin and Anhui provinces. Whole-plant dose-response results indicated that only population collected in Heilongjiang province (HLJ) had developed low level of resistance to nicosulfuron compared with the sensitive population (SD22). No known resistant mutation of ALS gene was found in HLJ population. The real-time fluorescence quantitative PCR results showed that the ALS gene copy number did not differ significantly between the HLJ and SD22 populations. However, the ALS gene expression in the HLJ was 2.07-fold higher than that of the SD22 population at 24 h after treatment with nicosulfuron. Pretreatment with the cytochrome P450 (CYP450) inhibitor malathion, piperonyl butoxide (PBO), and the glutathione S-transferase (GST) inhibitor 4-Chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) all partially reversed HLJ resistance. Among them, the synergistic effect of PBO and nicosulfuron is the most significant. This is the first report of resistance to nicosulfuron in crabgrass through ALS gene overexpression and possible metabolic resistance.

The synergistic effect of piperonyl butoxide on the molluscicidal potential of monoterpenes and phenylpropenes against Theba pisana

The synergistic effect of piperonyl butoxide on the molluscicidal potential of monoterpenes and phenylpropenes against Theba pisana

Metabolic resistance to deltamethrin is mediated by P450 and esterases in common bed bugs Cimex lectularius L. (Heteroptera: Cimicidae)

The infestations of Cimex lectularius L. (Heteroptera: Cimicidae) registered in the last decades have been influenced by several human activities, including international tourism and commerce. Moreover, the development of insecticide resistance and careless pest control strategies contributed to the dispersal of bed bugs. Given the complexity of the topic, distinguishing physiological and molecular mechanisms involved in resistance can help design proper control tools and limit the resistance spread. Here we determined the susceptibility to deltamethrin and imidacloprid in bed bugs collected in Italy. Also, we assessed the role of esterases and P450 monooxygenases by direct enzymatic activity measurement and inhibition by synergism bioassays. Our results showed that the field-collected colony exhibited high resistance ratios to imidacloprid and deltamethrin (757 and >60,000 times, respectively) compared to the susceptible colony. Moreover, resistant bed bugs showed increased activity of esterases and P450 monooxygenases. The synergistic effect of piperonyl butoxide (PBO) suggests the significant contribution of both enzymatic groups as detoxification pathways implicated in pyrethroid-resistant bed bugs. Further investigations are needed to unravel the biochemical and molecular basis involved in the resistant phenotype for developing novel strategies for pest control.

A comprehensive survey of permethrin resistance in human head louse populations from northwest Iran: ex vivo and molecular monitoring of knockdown resistance alleles

BackgroundHead louse infestation is an important public health problem, and expanding resistance to permethrin is a major challenge to its control. The mapping and detection of pyrethroid resistance are essential to the development of appropriate treatments and ensure the effectiveness of current measures. The aim of this study was to present the phenotypic and genotypic basis of permethrin resistance and identify knockdown resistance (kdr) mutations in head louse populations in northwestern Iran.MethodsAdult head lice were collected from 1059 infested girls in Ardebil, East Azerbaijan, West Azerbaijan and Zanjan Provinces, northwestern Iran. The toxicity of permethrin and the possible synergistic effect of piperonyl butoxide (PBO) on this toxicity were assessed using bioassays. Fragments of voltage-sensitive sodium channels (vssc) and cytochrome b (cytb) genes were amplified and analyzed for the detection of knockdown resistance (kdr) mutations and mitochondrial groups. Moreover, genotypes of the two hot spot regions of the vssc gene were determined by melting curve analysis of amplicons.ResultsA total of 1450 adult head lice were collected during 2016–2021. Live lice were exposed to a dose of 1% permethrin for 12 h, and the median lethal time (LT50) and time to achieve 90% mortality (LT90) were determined to be 6 and 14.8 h, respectively. Topical application of 2 and 16 ng permethrin per louse resulted in 25% and 42.11% mortality, respectively. Pre-exposure of samples to 3% piperonyl butoxide had no synergistic effect on the effects of permethrin. Analysis of the 774-bp vssc gene fragment showed the presence of the M815I, T917I and L920F mutations, wild-type and T917I mutation, in 91.6%, 4.2% and 4.2% of samples, respectively. Investigation of the mitochondrial cytb gene demonstrated the predominance of clade B. The frequency of domain II segment 4 (S4)-S5 kdr genotypes in mitochondrial groups was identical, and heterozygotes were present in 93.5% of samples. A significant difference was detected in the frequency of domain IIS1-S3 kdr genotypes, and the frequency of resistant alleles and heterozygotes was higher in clade B than in clade A.ConclusionsThe presence of kdr mutations in the vssc gene and the non-synergist effect of PBO indicate that pyrethroid target site insensitivity is the main resistance mechanism. This phenomenon and the high frequency of resistant alleles necessitate that new pediculosis management programs be developed. Further studies need to be conducted to identify all factors contributing this resistance and to develop alternative pediculicides.Graphical

Synergistic effect of piperonyl butoxide on the toxicity of alpha-cypermethrin and deltamethrin against pyrethroid-resistant german cockroach Blattella germanica (Blattodea: Ectobiidae) strains in Turkey

Synergistic effect of piperonyl butoxide on the toxicity of alpha-cypermethrin and deltamethrin against pyrethroid-resistant german cockroach Blattella germanica (Blattodea: Ectobiidae) strains in Turkey

Potential Environmental Health Risk Analysis of Neonicotinoids and a Synergist.

The extensive use of neonicotinoid pesticides has led to their widespread presence in the environment, resulting in considerable safety risks to the ecosystem and human health. In this study, we investigated the biotransformation behavior of a cocktail of multiple neonicotinoids and piperonyl butoxide (PBO) synergist in vivo and their potential environmental health risk. It was found that neonicotinoids with a cyano group, such as acetamiprid and thiacloprid, tended to accumulate in liver and spleen tissues, while others with nitro groups (imidacloprid, thiamethoxam, clothianidin, dinotefuran, and nitenpyram) were mostly excreted in urine. In the presence of the synergist PBO, the metabolism of neonicotinoids in vivo changed, mainly through the nitro reduction pathway, while a low abundance of related metabolites was observed in the conventional hydroxylation and demethylation metabolic pathways, due to inhibition of CYP450 enzymes by the synergist. Furthermore, DNA methylation damage in vivo was exacerbated by the induction of hydroxylamine metabolites formed in the intermediate process of neonicotinoid metabolism with the synergistic effect of PBO, which resulted in a higher level of the O6-methyldeoxyguanosine (O6-medG) biomarker in the liver. Therefore, during the comprehensive evaluation of pesticide environmental risks, attention should be paid not only to the co-exposure mode under real environmental conditions but also to the potential risks of intermediate metabolism and related intermediate metabolites. This study provides a referential strategy and theoretical support for the health risk assessment of co-exposure of chemicals.

Synergistic effect of piperonyl butoxide and emamectin benzoate on enzymatic activities in resistant populations of red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae).

Resistance to grain protectants in Tribolium castaneum (Herbst) is a serious threat to international grain trade. Frequent and overdose application of chemical insecticides is becoming a serious health hazard and cause environmental pollution. Resistance management approaches by using various synergists along with novel compounds has become more imperative to increase efficacy of environmentally safe insecticides. We have evaluated piperonyl butoxide (PBO) and emamectin benzoate mixtures for management of resistant field populations of T. castaneum. The collected strains had demonstrated 50 to 200% resistance already developed against emamectin benzoate as compared with deltamethrin susceptible reference strain. The inclusion of PBO along with emamectin significantly reduced this resistance by at least 28% and the LC50 were lowered from 5.12 to 1.9μg/ml with the highest synergism ration of 2.7 in resistant strain. Enzymatic assays clearly demonstrated that the specific activities of catalase and acetylcholinesterases were significantly decreased at an average of 80% and 60%, respectively, when PBO was included as a synergist at 1:2 ratio with emamectin benzoate. The results highlight the mechanism that renders the field population resistant to emamectin benzoate and suggests the synergistic role of piperonyl butoxide as a potent additive in grain protectants for resistance management.

Enhanced mortality in deltamethrin-resistant Aedes aegypti in Thailand using a piperonyl butoxide synergist

Aedes aegypti is the primary vector of dengue viruses in Thailand. Control of this mosquito continues to rely heavily on use of insecticides in various forms and applications. The synergistic effect of piperonyl butoxide (PBO), combined with deltamethrin against eight populations of Ae. aegypti collected from different regions in Thailand is presented. The standard WHO adult contact bioassays found all populations with low to moderate levels of resistance to deltamethrin alone (using a 0.05% discriminating concentration), with final mortalities ranging from 15.6 to 70%, while a laboratory strain was fully susceptible (100% mortality). Pre-exposure of female mosquitoes to 4% PBO for 1 h, followed immediately by exposure to deltamethrin for 1 h, significantly increased mortality in seven populations (64.8–98.1%) with the exception of mosquitoes derived from Lampang Province. The knockdown time (KDT) synergist ratios between deltamethrin only and PBO + deltamethrin ranged from 1.7 to 2.8 for KDT50 and 1.9 to 4.0 for KDT95. Between deltamethrin alone and mosquitoes exposed to PBO + deltamethrin, all resistant populations produced significant differences (P < 0.05) in final 24-h mortality, except marginally for Lampang (P = 0.053). The synergistic effects of PBO with deltamethrin-resistant Ae. aegypti suggest a combination of this synergist with deltamethrin or other pyrethroid compounds can significantly enhance the effectiveness of these insecticides against pyrethroid-resistant Ae. aegypti found commonly in Thailand.

Status of Resistance of Bemisia tabaci (Hemiptera: Aleyrodidae) to Neonicotinoids in Iran and Detoxification by Cytochrome P450-Dependent Monooxygenases.

Nine Bemisia tabaci (Gennadius) populations were collected from different regions of Iran. In all nine populations, only one biotype (B biotype) was detected. Susceptibilities of these populations to imidacloprid and acetamiprid were assayed. The lethal concentration 50 values (LC50) for different populations showed a significant discrepancy in the susceptibility of B. tabaci to imidacloprid (3.76 to 772.06mgl-1) and acetamiprid (4.96 to 865mgl-1). The resistance ratio of the populations ranged from 9.72 to 205.20 for imidacloprid and 6.38 to 174.57 for acetamiprid. The synergistic effects of piperonylbutoxide (PBO) and S,S,S-tributylphosphorotrithioate (DEF) were evaluated for the susceptible (RF) and resistant (JR) populations for the determination of the involvement of cytochrome P450-dependent monooxygenase and carboxylesterase, respectively, in their resistance mechanisms. The results showed that PBO overcame the resistance of the JR population to both imidacloprid and acetamiprid, with synergistic ratios of 72.7 and 106.9, respectively. Carboxylesterase, glutathione S-transferase and cytochrome P450-dependent monooxygenase were studied biochemically, for the purpose of measuring the activity of the metabolizing enzymes in order to determine which enzymes are directly involved in neonicotinoid resistance. There was an increase in the activity of cytochrome P450-dependent monooxygenase up to 17-fold in the resistant JR population (RR = 205.20). The most plausible activity of cytochrome P450-dependent monooxygenase correlated with the resistances of imidacloprid and acetamiprid, and this suggests that cytochrome P450-dependent monooxygenase is the only enzyme system responsible for neonicotinoid resistance in the nine populations of B. tabaci.

Synergistic effect of piperonyl butoxide on acute toxicity of pyrethrins to Hyalella azteca.

A series of acute toxicity tests with the amphipod Hyalella azteca was performed to quantify the synergistic effect of piperonyl butoxide (PBO) on pyrethrin toxicity. Concentrations of PBO <4 µg/L caused no toxicity enhancement, whereas toxicity increased with PBO concentrations between 4 µg/L and 15 µg/L. Additive toxicity calculations showed that true synergism accounted for an increase in pyrethrin toxicity (decrease in median lethal concentration) of 1.4-fold to 1.6-fold and varied only slightly between 4 µg/L and 15 µg/L PBO, whereas direct toxicity of PBO accounted for an additional increase in mixture toxicity (up to 3.2-fold) that was proportional to PBO concentration. The results can be used to assess the risk of measured or predicted co-occurring concentrations of PBO and pyrethrins in surface waters. Environ Toxicol Chem 2016;35:2111-2116. © 2016 SETAC.

The effects of fixed-bed drying on the yield and composition of essential oil from long pepper (Piper hispidinervium C. DC) leaves

Piper hispidinervium C.DC (Piperaceae) is popularly known as long pepper. It grows in degraded areas of natural fields in the state of Acre, Brazil. Its leaves are 3 to 4 % essential oil rich in safrole, within the range of 90 to 94 %. In the chemical industry, safrole is an important raw material, mainly due to two of its derivatives: heliotropin, which is widely used as a fragrance and flavoring agent, and piperonyl butoxide (PBO), a vital ingredient of pyrethroid insecticides. Natural pyrethrum in particular would not be an economical insecticide without the synergistic effect of PBO; therefore, its industrial future is linked to the continued availability of PBO. As a fragrance, safrole has many applications in household products such as floor waxes, polishes, soaps, detergents and cleaning agents. In this work, leaves were dried in a fixed-bed dryer using different drying-air temperatures (35, 40, 45, 50, 55 and 60 oC) and drying times (900, 2700 and 3600 seconds). Essential oil was extracted by cohobation (meaning that the condensed water that comes out of the flask is recycled) from both raw and dried leaves. The essential oil yield and safrole content are susceptible to rapid loss of moisture by Piper hispidinervium C. DC leaves. It was observed that the essential oil yield increased twice after the drying process. However, safrole content decreased about 20 percent when temperature was above 50 oC and drying times were more than 2700 minutes.

Life stage variations in insecticidal susceptibility and detoxification capacity of the beet webworm, Pyrausta sticticalis L. (Lep., Pyralidae)

Abstract: Adults and larvae of the beet webworm Pyrausta sticticalis (Lep., Pyralidae) are susceptible in varying degrees to insecticides of different chemical classes. Comparative toxicity tests as well as the synergistic effects of piperonyl butoxide, S,S,S‐tributyl phosphorotrithioate and diethylmaleate showed that variation in toxicities of beet webworm developmental stages to organophosphorus compounds and carbaryl is partly due to the activities of detoxification enzymes. Specific activities of monooxygenases, esterases and glutathione S‐transferase were higher in fifth instars than in adults. Studies of the post‐treatment fate of 14C‐labelled malathion and 3H‐trans‐permethrin after application indicated that both compounds had a rapid rate of cuticular penetration, internal accumulation and excretion of applied toxicants and their metabolites by larvae. Adults of beet webworm had a lower sensitivity of acetylcholine esterase to the inhibition of carbaryl than the larvae.

Laboratory Selections of Populations in the Citrus Red Mite, &lt;i&gt;Panonychus citri&lt;/i&gt; (MCGREGOR), with Hexythiazox and Their Cross Resistance Spectrum

Laboratory selection experiments for resistance and for susceptibility with hexythiazox were conducted using Haibara strain of citrus red mite, Panonychus citri MCGREGOR collected from a citrus orchard at Haibara Agricultural Research Station (Nippon Soda Co., Ltd.) in Shizuoka Prefecture, Japan. The mites had been selected with hexythiazox 17 times in the orchard. A high level of hexythiazox resistance developed with 6 successive laboratory selections for resistance, and the resistance ratios at LC 50 were 23,000 and 4450 compared with the unselected strain and parental generation for laboratory selection, respectively. After 5 selections for susceptibility, the strain became more susceptible to hexythiazox, and the susceptibility ratio at LC 50 was 0.59. In the resistant strain, the levels of the resistance were high at all developmental stages including eggs laid by treated adult females. No synergistic effects of piperonyl butoxide with hexythiazox were observed on the activity against eggs and eggs laid by treated females in the resistant strain. Among 20 miticides investigated about their efficacies against the hexythiazox resistant strain, clofentezine, flufenoxuron and flucycroxuron showed low activities to the resistant strain.

Mode of action of piperonyl butoxide as herbicide synergist of atrazine and terbutryn in maize

Piperonyl butoxide, a known insecticide synergist, enhances herbicidal activity of atrazine and terbutryn in maize seedling(s). When applied to maize seedling in combination with either atrazine or terbutryn, piperonyl butoxide enhances foliar uptake of both herbicides and leads to a light-dependent damage to membrane integrity, indicating free radical involvement. Rapid changes in the glutathione level were also observed in plants treated either with piperonyl butoxide alone or in combination with atrazine. Furthermore, in piperonyl butoxide-treated maize, terbutryn (but not atrazine) degradation is inhibited as compared to those treated with terbutryn alone. In vitro studies using microsomal fraction(s) isolated from etiolated maize seedlings have shown that either piperonyl butoxide or terbutryn bind to cytochrome P-450 monooxygenases forming a distinct shift in absorbance spectrum with a peak at 438 nm. Piperonyl butoxide caused about 50% inhibition in terbutryn conversion to polar products by maize microsomal fraction(s) containing NADPH and O 2, indicating that piperonyl butoxide inhibits terbutryn degradation mediated by cytochrome P-450 monooxygenases. Piperonyl butoxide had little effect on atrazine degradation in treated plants. High concentration(s) of piperonyl butoxide were needed to inhibit the in vitro activity of glutathione-S-transferase, isolated from maize leaves. We suggest that the synergistic effect of piperonyl butoxide is due to enhanced herbicide penetration, induced membrane damage, and/or inhibition of cytochrome P-450-mediated herbicide metabolism.

Sexual Differences in Insecticide Susceptibility and Synergism with Piperonyl Butoxide in the Leafminer Parasitoid Diglyphus begini (Hymenoptera: Eulophidae)

Susceptibility of males and females of the Liriomyza leafminer parasitoid Diglyphus begini (Ashmead) to methomyl, oxamyl, fenvalerate, and permethrin was Compared with laboratory bioassays. For each insecticide and five populations tested, males were more susceptible than females. Differences in LC50s between the sexes ranged from 1.3- to 15.7-fold and were greater in resistant Compared with susceptible populations. Tibia length was significantly less for male than female D. begini. Size differences ranged from 1.1- to 1.2-fold. Piperonyl butoxide synergized oxamyl and fenvalerate in males and females, suggesting that oxidative detoxification was important in both sexes. The addition of piperonyl butoxide to oxamyl affected both sexes similarly. The synergistic effect of piperonyl butoxide with fenvalerate was significantly greater for females than males, suggesting greater oxidative detoxification of fenvalerate in females than males.

Increased herbicidal activity of triazine herbicides by piperonyl butoxide

Piperonyl butoxide (PB) is a known Synergist which enhances the activity of insecticides by inhibiting their biotransformation to less active products. We have evaluated the possible use of PB as a herbicide synergist using triazine herbicides in sensitive, tolerant, and resistant plants. The effects of PB, triazine herbicides, and their combinations were examined in whole plants as well as in chloroplasts isolated from triazine-sensitive (S) and -resistant (R) weed biotypes. PB itself, applied postemergence (0.1–0.5%, v/v), was slightly toxic to the plants tested. However, foliar application of PB combined with atrazine, terbutryn or prometryn to maize seedlings significantly increased the phytotoxicity of the herbicides. Low rates of atrazine, prometryn, and terbutryn in a tank-mixture with PB, effectively controlled Solatium nigrum L. and Abutilon theophrasli Medik. PB enhanced atrazine efficacy in both S and R biotypes of Lolium rigidum Gaud. The synergistic effect of PB was evident also in vitro when atrazine and methabenzthiazuron were used to inhibit photosystem II electron transport in chloroplasts isolated from resistant weeds. These data demonstrate the potential of PB as a herbicide synergist and its possible utilization as an aid for improving the activity of triazine herbicides in sensitive, tolerant and resistant plants.

Synthesis and insecticidal activities of unsymmetrical bis‐arylalkyl ketones. A new structural concept in pyrethroids

AbstractSeventeen unsymmetrical bis‐arylalkyl ketones were synthesised and their insecticidal activities against Musca domestica, Locusta migratoria, Drosophila melanogaster, Dysdercus cingulatus, Aedes aegypti and Tetranychus urticae were tested. The synergistic effect of piperonyl butoxide on the activities of some of the new ketopyrethroids against Musca domestica was also determined. Several structural variations, including substituent exchange in the aryl moieties, the position of the ketone function and increase or decrease of the length of the carbon chain connecting the two aryl moieties, were made in order to examine the structure‐activity relationship. All biological activities were compared with the activity of the ether pyrethroid 2‐(4‐ethoxyphenyl)‐2‐methylpropyl 3‐phenoxybenzyl ether (MTI‐500).

In vivo andIn vitro studies on synergism with anticholinesterase pesticides in the snailLymnaea acuminata

The synergistic effects of piperonyl butoxide (PB)2, sulfoxide (SU), and dimethyl amino aniline (DAA) used in conjunction with two organophosphate pesticides (phorate and formothion) and two carbamate pesticides (mexacarbate and carbaryl) were examined in terms of the LC50 and acetylcholinesterase (AChE) inhibition in the snailLymnaea acuminata. The three synergists reduced the LC50 of phorate, formothion, mexacarbate, and carbaryl at exposure periods ranging from 24 to 144 hr. PB and SU had strong synergistic action; DAA had little effect; the highest synergistic ratio (70) was found with carbaryl and PB. The synergists enhanced thein vitro inhibition of cholinesterase caused by the pesticides; the synergistic effect onin vitro inhibition, however, was lower, compared to the change in the LC50.

Metabolic detoxication and synergistic ratio of lindane analogs in house flies

Biodegradability of lindane analogs using house fly whole body, microsomes, and microsome supernatant fraction was examined. It decreased in the order of alkoxy ∼ methylthio > methyl analogs > lindane in the whole body experiments, as well as with microsomes in the presence of NADPH. With the supernatant in the presence of glutathione, a different trend was observed. The synergistic effects of piperonyl butoxide when used together with lindane analogs were mostly explained in terms of the inhibition of the microsomal metabolism. Piperonyl butoxide was also shown to inhibit the penetration of compounds into the fly body and to make the central nervous system of the American cockroach less sensitive to the action of insecticides causing after and repetitive discharges. It was observed that the value of the percentage of metabolic disappearance of insecticides after a certain period decreases as the dose level initially applied in the whole body experiments increases. The synergistic ratio parallels the percentage of disappearance value after the insecticidal activity test period when a dose corresponding to the unsynergized LD 50 is initially applied. When quantitative comparisons are required for biodegradability of insecticides using house flies as the test insects, it should be on the basis of direct metabolism experiments using a fixed dose throughout the series of insecticides, but not on the basis of the synergistic ratio.