Emamectin Research Articles

Spatiotemporal Dynamics of Trunk-Injected Pesticide Residue for Management of Pine Wilt Disease in Pinus koraiensis

This study focused on the persistence, distribution, and efficacy of trunk-injected pesticides in Pinus koraiensis (Korean pine) with regard to controlling pinewood nematodes (PWNs, Bursaphelenchus xylophilus), the causative agent of pine wilt disease (PWD). In this study, we compared pesticide residues in the needles and branches of Korean pine, revealing significant declines in pesticide residues over time after treatments were applied. Notably, abamectin residues decreased from 0.2325 mg/kg to 0.0901 mg/kg in branches over a period of 18 months. In contrast, emamectin benzoate showed a variation in residue decline depending on the formulation, with the residue level in branches decreasing from 0.1220 mg/kg to 0.0328 mg/kg over the same period. From a spatial perspective, the results revealed minimal differences in pesticide residue at varying tree heights, although a decrease in upper canopy residue was observed in some cases. The nematicidal efficacy test demonstrated that none of the treated trees developed PWN symptoms. Overall, the findings suggest that the trunk-injected pesticides abamectin and emamectin benzoate can persist for two years, with the residue levels being sufficient to prevent PWN propagation, even when the levels are below critical inhibition concentrations.

Biological effects of glyphosate and emamectin benzoate based pesticides on the freshwater prawn Macrobrachium macrobrachion juveniles

Biological effects of glyphosate and emamectin benzoate based pesticides on the freshwater prawn Macrobrachium macrobrachion juveniles

Toxicity and residual activity of insecticides to Grapholita molesta (Lepidoptera: Tortricidae) in apple orchards: implications for insecticide resistance management.

Organophosphate (OP) insecticides have been used to control Grapholita molesta (Busck, 1916) in Brazil since 1990. However, the evolution of pest insecticide resistance and toxicological reassessments has led to the replacement of OPs with other chemical groups. This study evaluated the toxicity of the insecticides abamectin + cyantraniliprole (1.1 + 3.7g a.i./100L-1), acetamiprid + etofenproxi (9.1 + 16.5g a.i./100L-1), emamectin benzoate (0.5g a.i./100L-1), Sophora flavescens (Fabales: Fabaceae) (22.8g a.i./100L-1), phosmet (87.5g a.i./100L-1), and indoxacarb (11.2g a.i./100L-1) to eggs, larvae, and adults of G. molesta. Additionally, the residual activity of these insecticides in apple orchards was assessed, and the diagnostic concentration for resistance monitoring was estimated using LC99 values (Lethal Concentration that causes 99% mortality in a susceptible population). In larval studies, all insecticides resulted in mortality rates of more than 90%. The insecticide acetamiprid + etofenproxi reduced larval hatching by 99%. This insecticide with phosmet and Sophora flavescens caused over 80% adult mortality and had a 14-day residual activity in apple orchards. The estimated LC99 (μg.ml-1) for resistance monitoring were 1.75 (indoxacarb), 6.45 (metaflumizone), 9.10 (acetamiprid + etofenproxi), 9.67 (Sophora flavescens), 36.13 (phosmet), and 45.61 (abamectin + cyantraniliprole). The insecticides evaluated have high toxicity for G. molesta, being new tools for integrated pest management and for insecticide resistance management in apple orchards.

Impact of the entomopathogenic fungus Metarhizium anisopliae (Metchnikoff ) Sorokin on Spodoptera frugiperda (J.E Smith), an invasive maize pest in Chad

The invasion of agricultural plots by Spodoptera frugiperda (J.E Smith) constitutes a serious constraint to the sustainable maize production in Chad. Since then, farmers have unsuccessfully used available chemical insecticides to control this pest at that respect, the present study evaluated the bio-efficacy of two strains (Chinese and Senegalese) of Metarhizium anisopliae on the pest, both under laboratory and field conditions. Laboratory results showed that both strains were virulent against FAW resulting in a mortality of 90 ± 5.77% for the strain from Senegal and 75 ± 5.00% for that from China. In the field, significant differences were observed among the four treatments tested, namely the two M. anisopliae strains (2.5 kg/ha), the control and Emamectin benzoate (20g/ha) for both the infestation of maize plants and FAW densities (P <0.05). Meanwhile, maize grain yields were significantly the highest in plots treated with Emamectin benzoate followed by plots treated with either of the two strains of the fungus whose yields were statistically similar (df = 3; F = 27.13; P <0.0001). This biopesticide was more virulent under laboratory and field conditions and could be a promising biological control agent against S. frugiperda as an alternative to synthetic insecticides. However, additional studies that evaluate the implementation cost of the microbiological control are very necessary for more objective and robust conclusions. Key words: Fall armyworm, microbiological control, Zea mays, Emamectin benzoate, biopesticides.

Antiparasitic effect of imidacloprid on the copepodite and adult stages of Caligus rogercresseyi

In Chile, there are currently eight authorized pharmaceutical chemical compounds for the control of sea lice (Caligus rogercresseyi), namely emamectin benzoate, diflubenzuron, lufenuron, hexaflumuron, hydrogen peroxide, deltamethrin, cypermethrin and azamethiphos; however, being this range of tools considered scarce, moreover, loss of sensitivity to some of these compounds have been described in previous studies. Imidacloprid is a neonicotinoid synthetic insecticide that was authorized in Norway in 2021 and has revealed good efficacy in controlling Lepeophtheirus salmonis on salmon farms; however, it has not been authorized for use in Chile. Therefore, in this study, we investigated the efficacy of imidacloprid on the copepodite and adult stages of C. rogercresseyi, which, to our knowledge, has not been investigated in previous studies. We observed that imidacloprid immobilized the parasite at both stages; however, adults were able to recover after the exposure, with 50 % of the adults exposed to concentrations <40 ppm for 24 h recovering, suggesting that a concentration > 20 ppm is required for 100 % mortality of this parasite. In contrast, the copepodite stage was immobilized at 20 ppm, suggesting that copepodites are more sensitive to imidacloprid than the adults. Further studies are required to understand the biological responses of the different stages of C. rogercresseyi to design effective control strategies, improve our understanding of the mechanisms of imidacloprid, and determine the optimal concentrations for control of the parasite.

Impact of decontamination and processing methods on insecticide residues in green and red chilli (Capsicum annum L.) by LC- MS/MS

The study aimed to evaluate various decontamination and processing methods for the removal of pesticide residues in chilli, focusing on emamectin benzoate, fipronil, spirotetramat, and tolfenpyrad. The LC-MS/MS instrument parameters were standardized and method was validated for identification and quantification of residues in both green and dry chilli. In green chilli, treatments such as soaking in 2 per cent NaCl solution showed promising results in reducing pesticide residues. The tested decontamination treatments are effective for handling emamectin benzoate and tolfenpyrad residues in green chilli. However, fipronil residues remained above Maximum Residual Limits even after decontamination treatments, indicating the need for careful application and monitoring. In red chilli, processing methods such as sun-drying and pan-frying led to increased residues due to concentration effects during drying. Despite efforts, some residues remained above regulatory limits, emphasizing the importance of adhering to pre-harvest intervals to minimize residues in processed chili products.

Side effects of insecticides used for management of Tuta absoluta Meyrick (Lepidoptera: Gelechidae) on the biocontrol agent Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae)

Trichogramma brassicae is one of the most important egg parasitoids of many pests including South American tomato pinworm, Tuta absoluta (Lepidoptera: Gelechiidae). In agrosystems, the function of parasitoids can be affected by the application of insecticides. To use biological control agents and pesticides simultaneously in pest management, it is necessary to know the potential effect of pesticides on biological control agents. In this study, the lethal and sublethal effects of four insecticides (flubendiamide, emamectin benzoate + lufenuron, thiocyclam, and spinosad) frequently used to control T. absoluta, were investigated on its parasitoid Trichogramma Brassicae Bezdenko (Hymenoptera: Trichogrammatidae), under controlled laboratory conditions. The results showed that spinosad with an LC50 value of 0.73 mg a.i./ L was highly toxic against adults of T. brassicae in comparison to flubendiamide (4.09 mg a.i./ L), emamectin benzoate + lufenuron (4.17 mg a.i./ L), and thiocyclam (9.59 mg a.i./ L). Furthermore, key demographic parameters such as net reproductive rate (R0), intrinsic rate of increase (rm), mean generation time (T), and doubling time (DT) were significantly decreased after exposure of T. brassicae to the LC30s of spinosad, thiocyclam, flubendiamide, and emamectin benzoate + lufenuron compared to the control. In the light of our results, the four insecticides should be used cautiously in T. absoluta integrated management programs. While the thiocyclam can be combined with the T. brassicae, the flubendiamide and emamectin benzoate + lufenuron are not recommended in the presence of this parasitoid. The use of spinosad should be avoided concomitantly with the release of T. brassicae.

Combating Spodoptera frugiperda (Lepidoptera: Noctuidae) with Moringa-Synthesized Silica Nanoparticles and Its Combination with Some Insecticides.

The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is a major agricultural pest known for developing resistance to insecticides. This study investigated a novel approach to manage FAW by silica nanoparticles (SiNPs) synthesized from eco-friendly leaf extract of Moringa oleifera Lam. (Moringaceae). This green synthesis method offers a sustainable and potentially safer alternative to traditional chemical processes. SiNP formation was confirmed by various techniques: UV-visible spectrophotometer, X-ray spectroscopy with energy-dispersive (EDX), scanning electron microscopy (SEM), and dynamic light scattering (DLS). The effectiveness of SiNPs alone and their combination with three common insecticides (emamectin benzoate, indoxacarb, and chlorpyrifos) were evaluated against third instar larvae of fall armyworm. While SiNPs after 24h by leaf dipping method recorded limited insecticidal activity (LC50 = 9947.59mg/L), it significantly enhanced the potency of all three insecticides. Combining SiNPs with emamectin benzoate resulted in the most dramatic increase in effectiveness compared to the insecticide alone with LC50 = 0.295mg/L and 0.42mg/L, respectively. This research suggests that moringa extract can be a valuable resource for the green synthesis of nanoparticles potentially useful in pest control. This approach could potentially reduce the amount of insecticide needed for effective pest control, leading to a more sustainable and environmentally friendly agricultural practice.

Optimized emamectin benzoate trunk injection: addressing temperature limitations for pine wilt disease control.

Pine wilt disease (PWD), caused by the pinewood nematode Bursaphelenchus xylophilus, poses a significant threat to global forestry, resulting in extensive economic and ecological damage. Traditional trunk injection agents (TIAs) are limited by environmental factors, such as high winter temperatures and vigorous resin flow, particularly in southern China. This study aimed to develop an ordinary temperature trunk injection agent (OTTIA) for year-round application and to evaluate its performance under high-temperature conditions in comparison to commercial TIAs. Extensive laboratory and field tests identified N,N-Dimethylformamide (DMF) and benzyl acetate as optimal solvents and Tween-40 as an effective emulsifier for the OTTIA formulation. The new agent was fully absorbed by Pinus massoniana within 3 h at temperatures exceeding 30 °C, outperforming existing commercial agents. Treated trees maintained comparable emamectin benzoate (EB) levels but achieved lower LC90 lethal concentration values (27.65 mg L-1), indicating greater efficacy. The OTTIA provided protection against PWD for ≤360 days postinjection. The development of OTTIA marks a significant advancement in PWD management, offering an effective solution for high-temperature regions and potentially transforming year-round treatment strategies. The results highlight the critical role of optimizing solvent and emulsifier combinations to enhance the efficacy and application of trunk injection agents, contributing to sustainable forest management and improved protection against PWD. © 2024 Society of Chemical Industry.

Investigation of resistance ratios and resistance mechanisms of Cydia pomonella (L.) (lepidoptera: Tortricidae) populations collected from apple orchards in Isparta (Türkiye) against some insecticides

The codling moth, Cydia pomonella is an important pest that causes significant economic losses in apples and walnuts in the world. The aim of this study was to investigate, for the first time in Türkiye, the resistance status and resistance mechanisms of codling moth, Cydia pomonella against indoxacarb, deltamethrin and emamectin benzoate. All apple orchard populations developed resistance ratios ranging from 3.38 to 22.37-fold to deltamethrin, 5.67–29.87-fold to indoxacarb and 1.46–3.05-fold to emamectin benzoate. The interaction of some synergists triphenyl phosphate (TPP), piperonyl butoxide (PBO) and diethyl maleate (DEM) with indoxacarb and deltamethrin was analyzed in the susceptible, MAREM and Tepeli populations with moderate resistance to indoxacarb and deltamethrin. While indoxacarb + TPP showed a significant synergistic effect only in MAREM population, a significant synergistic effect was observed with indoxacarb + TPP and indoxacarb + PBO in Tepeli population. The activities of detoxifying enzymes [esterase, glutathion –S– transferase (GST) and cytochrome P450 monooxygenase (P450)] studied by biochemical methods showed some variation depending on the population. The results of biochemical analyses showed that esterase and GST enzyme activities of all populations was between 0.51 and 0.94, 0.77 and1.29 mOD min−1mg−1 proteins, respectively. The P450 enzyme activities ranged from 0.53 to 0.78, RFU min−1mg−1 proteins. In addition, the L1014F knockdown mutation (CTT to TTT) corresponding to leucine to phenylalanine amino acid substitution of the voltage-gated sodium channel in Cydia pomonella was determined in MAREM and Tepeli populations. It was determined that while MAREM and Tepeli populations developed moderate resistance, the other populations developed a low level resistance to deltamethrin and indoxacarb. On the other hand, all populations developed a low level resistance to emamectin benzoate. The P450 and esterase enzyme activities were significantly higher in MAREM and Tepeli populations which were resistant to deltamethrin and indoxacarb than the susceptible population. In addition, a Kdr point mutation L1014F was detected in the deltamethrin resistant MAREM and Tepeli populations.

Regional changes of maximum dose insecticide responses in diamondback moth (Lepidoptera: Plutellidae) populations from Georgia and Florida, USA.

Maximum dose bioassays were conducted to assess the efficacy of multiple registered active ingredients for diamondback moth (DBM), Plutella xylostella (L.), control in Georgia and Florida from 2021 to 2023 as a follow-up to an earlier study. Low efficacy (<40% mortality) was recorded for the highest labeled rate of Bacillus thuringiensis var. kurstaki strain ATBS-351 in Georgia, as well as chlorantraniliprole, cyantraniliprole, and cyclaniliprole in Georgia and Florida. The active ingredients with the highest efficacy (>80% mortality) in both states were naled, emamectin benzoate, and spinetoram. Independent analysis of data by state indicated that the efficacy of bifenthrin, chlorantraniliprole, cyantraniliprole, tolfenpyrad, and methomyl was higher in Florida populations than in Georgia populations. In addition, a comparison of these data to a recent DBM maximum dose survey in the same region suggested that these DBM populations have rapidly developed high levels of resistance to cyantraniliprole and cyclaniliprole. This work provides growers in the region with a recent ranking of insecticide efficacy that documents the loss of control for certain active ingredients, which assists pest managers in the planning of ongoing insecticide rotations for DBM resistance management.

The impact of lethal and sub-lethal exposure of emamectin benzoate on populations of Spodoptera litura (Lepidoptera: Noctuidae) under laboratory conditions

Emamectin benzoate is an avermectin bio-insecticide commonly used for managing several insect pests including Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), a major polyphagous pest of many cultivated crops. The current study was conducted to evaluate the effects of emamectin benzoate on the fitness of S. litura populations exhibiting differential susceptibility to insecticide. The selection process and all the bioassays were carried out using 6-day-old 2nd instar larvae of S. litura. A field-collected population of S. litura was divided into two groups: one selected with emamectin benzoate for eight generations (EB-Sel) and the other kept unexposed (Unsel-Lab) to insecticide in the laboratory. An increase in resistance ratio from 1.71-fold in the F1 generation to 22.54-fold in the F8 generation of the EB-Sel population was observed compared to the Unsel-Lab (F8) population. The EB-Sel and Unsel-Lab populations were treated with their respective lethal and sub-lethal concentrations which resulted in an extended development period, decreased larval survival, and adult emergence along with increased morphological abnormalities in adults. Significant reductions were observed in both male and female longevity, fecundity, egg hatching, net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ) in EB-Sel and Unsel-Lab populations. Higher concentrations of the insecticide also reduced the relative fitness (Rf) of S. litura larvae, with maximum effect at LC50 of the EB-Sel population where the Rf value was 0.32 compared to the Unsel-Lab population. Both populations have been affected by emamectin benzoate exposure, however, the impact was more pronounced in the EB-Sel population indicating fitness costs. Our results suggested the fitness cost linked to emamectin benzoate resistance in S. litura which might favor managing insecticide resistance by reducing the frequency of resistant alleles by removing selection pressure. Consequently, our research provides significant insights to devise better pest management strategies for S. litura.

Effects of Botanicals and Synthetic of Insecticides on Field Emergence and Crop Establishment in Mungbean [Vigna radiata (L.) Wilzeck

Mungbean, is a drought-resistant, green manure crop and suitable for dry land as a major pulse crop in India. India is the largest producer and consumer of pulses, which improve soil properties, provide nutritious fodder and prevent soil erosion. However, pests like bruchids can destroy 60% of production, necessitating the use of eco-friendly seed protectants. Laboratory studies were conducted at Acharya Narendra Deva University of Agricultural and Technology, Ayodhya, using mungbean seed cv. IPM-2-3. Seeds were mixed with seed protectants and stored in gunny bags. Field emergence and crop establishment were tested and data were analyzed using a Completely Randomized Design with three replications. Seed protectants and insecticides are effective in maintaining field emergence and crop establishment in mungbean. Emamectin benzoate, Sivanto prime and Gorakhmundi powder are the best treatments, with maximum field emergence and minimum establishment influenced by environmental factors. These findings are supported by various studies. Emamectin benzoate and Neemoz gold were found to be effective insecticides for field emergence and crop establishment in mungbean, with the latter recommended for storability and field establishment.

Efficacy of Alternative Insecticides against Dusky Cotton Bug (Oxycarenus laetus) to Improve Yield Losses in Cotton Crops through Residue-based Bioassay

The study evaluates the efficacy of leufenuron, emamectin benzoate, and thiamethoxam against the Dusky Cotton Bug (Oxycarenus laetus Kirby) using residue-based bioassay methods. Key findings indicate that emamectin benzoate showed the highest efficacy with the lowest LC50 value, making it the most potent insecticide among those tested. Leufenuron and thiamethoxam followed, displaying moderate effectiveness. The results highlight the comparative advantages of emamectin benzoate in controlling Dusky Cotton Bug populations, suggesting its potential role in integrated pest management strategies. This study underscores the need for environmentally friendly alternatives to traditional insecticides in mitigating yield losses in cotton production.

Bioassay of Plant-based and Synthetic Insecticides for the Management of Tomato Leaf Miner, Tuta absoluta (Meyrick) in Open-field Conditions in Salyan, Nepal

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most parts of Nepal and threatens tomato production. Their management primarily relies on insecticides in Nepal. Market-available and locally-madeplant-based pesticides are not equally effective in managingT. absoluta. Therefore, this study aimed to evaluate the effectiveness of such potential insecticides in managing T. absoluta in open-field conditions. This study was carried out in the Salyan district of Nepal in 2021 and treatments were designed in a randomized complete block design (RCBD)with seven treatments and three replications. All treatments were sprayed at12-dayintervalsfor two times. The treatments used were Emamect in benzoate 5% SC, Imidacloprid 17.8 SL, Jholmol (botanical mixture extract and urine mixture), Chlorantraniliprole 18.5 SC, Spinosad 45 SC, Azadirachtin 300ppm and Control. The results showed that the lowest percentage of leaves and fruit damage was recorded in Chlorantraniliprole 18.5 SC and Spinosad 45 SC sprayed plots. Insecticide efficiency was ranked as Chlorantraniliprole &gt; Spinosad&gt;Ema-mectin Benzoate &gt; Azadirachtin &gt;Imidaclroprid&gt;Jholmol&gt;Control. Marketable yield was obtained highest in Chlorantraniliprole (85.26 t/ha) treated plots followed by Spinosad (79.26 t/ha); both were not significantly different. This study provides an opportunity to select the most suitable and effective pesticides for the management of tomato leaf miners and can be used in integrated pest management strategies as a selective insecticides.

In vitro and Silico Exploration of the Insecticidal Properties of Lavandula multifida L. Essential Oil and its Binary Combinations with Cyantraniliprole and Emamectin benzoate on Spodoptera frugiperda (Lepidoptera: Noctuidae)

Control methods have faced challenges in effectively managing the spread and damage caused by the fall armyworm (FAW), Spodoptera frugiperda, across various crops worldwide, highlighting the need for more sustainable and integrated approaches. This study explored the insecticidal effect of the essential oil (EO) of lavender (LV) (Lavandula multifida L.), cyantraniliprole (CY), and emamectin benzoate (EM) insecticides on FAW larvae. Toxicity, biological, and biochemical assays were employed to elucidate the impact of the two insecticides individually or combined with LV EO. Additionally, in silico molecular docking investigations were performed for eucalyptol (the major component of LV EO) and for CY against the acetylcholine esterase (AChE) enzyme (PDB ID: 6xyu) and cytochrome P450 (PDB ID: 2q6n). EM was the most toxic compound to FAW larvae with an LC50 of 0.0073 mg L−1, followed by CY and LV EO. The chi-square (χ2) test confirmed the synergistic effect of the LV EO/CY combination and the antagonistic effect LV EO/EM combination on FAW larvae. Biological development studies revealed that both LV EO/CY and LV EO/EM combinations impacted the larval and pupal durations. The biochemical assays indicated that the P450-specific activity was activated by LV EO (at LC25), CY (at LC25 & LC50), and their binary combination (at LC25:LC25). In addition, the LV EO/CY combination significantly activated the AChE and GST-specific activity, and the LV EO/CY combination and CY (at LC50) significantly activated α-esterase- specific activity. Molecular docking investigations revealed energy scores (S) of −6.7729 and −7.7644 kcal/mol for eucalyptol and CY, compared to −7.0993 kcal/mol for PDB ID: 6xyu ligand. The current results can serve as baseline data for utilizing the LV EO/CY combination in the integrated pest management (IPM) of FAW.

Sublethal effects of emamectin benzoate on biological characteristics and the expression of vitellogenin (SgVg) and its receptor in Sclerodermusguani

Emamectin benzoate (EMB) is a commonly used insecticide for controlling agricultural and forest pests. To facilitate its rational use in integrated pest management (IPM), the sublethal effects of EMB on the development and reproduction of Scleroderma guani were evaluated. Sublethal doses of EMB (LD10 and LD30) significantly reduced the longevity and fecundity of F0 females. In the F1 generation, sublethal doses significantly reduced larval development duration and male longevity but significantly extended female longevity. Additionally, the LD30 treatment significantly decreased the number of laid eggs in F1 females by 20.72% compared with the control group. The net reproductive rate (R0) was significantly declined by the LD30 treatment compared with the control group (CK). Furthermore, the mean generation time (T) was significantly extended in both LD10 and LD30 treatment groups. Compared to the control group, the expression of SgVg and SgVgR genes in the LD10 and LD30 groups was significantly lower, which may be a crucial factor for the reduced fecundity of the females. These results indicate that sublethal doses of EMB significantly reduced adult longevity and fecundity of S. guani. The findings are practical for developing IPM strategies for forestry pests using S. guani and EMB.

Efficacy of Certain Bio-Pesticides against the Major Insect Pests of Broccoli (Brassica oleracea var. italica L.)

The field experiment was undertaken at the Experimental Farm, Department of Entomology, School of Agricultural Sciences (SAS), Medziphema Campus, Nagaland University, during the period of November 2021 to February 2022 to study the efficacy of certain bio-pesticides against major insect pests of broccoli. The experiment was conducted using Randomized Block Design (RBD) with six treatments including control and replicated four times. The study revealed that Indian cabbage white, Pieris spp. and green peach aphid, Myzus persicae have been found to be the major insect pest in broccoli. It is recorded that the highest (73.49%) population reduction of M. persicae was obtained from the plot treated with emamectin benzoate 5% SG and the highest (90.16%) population reduction of Pieris spp. was recorded on the plot treated with spinosad 45% SG. Therefore, the study concluded that use of bio-pesticides offers a great efficacy in controlling the pest and diminish the pesticides related issue.

Efficacy of new molecule of insecticide, Emamectin benzoate against polyphagous pest, Helicoverpa armigera (Hubner): A review

Efficacy of new molecule of insecticide, Emamectin benzoate against polyphagous pest, Helicoverpa armigera (Hubner): A review

Validation of LCMS/MS based method for residual estimation of tolfenpyrad and emamectin benzoate in brinjal and cauliflower and their risk assessment

Dissipation and risk assessment of tolfenpyrad and emamectin benzoate was carried out on brinjal and cauliflower after two applications of combination formulation of Tolfenpyrad 18.75 % + Emamectin benzoate 0.94 % w/w SC@ 7.0 (x) and 8.75 (1.25x) g a.i. ha−1. Rapid multi-residue analytical methodology for triple-quadrupole mass spectrometric analysis (LC-MS/MS) was validated to be linear, specific, accurate with acceptable matrix effects, recovery, uncertainty with limit of detection (LOD) of 0.003 mg kg−1and limit of quantification (LOQ) of 0.01 mg kg−1 for both tolfenpyrad and emamectin benzoate. Field experiment revealed that initial deposits of tolfenpyrad were 0.15 and 0.22 mg kg−1in brinjal and 0.54 and 0.85 mg kg−1 in cauliflower head, at x and 1.25 x dose, respectively that reached below LOQ at 10 days in brinjal (both doses) and 5 and 7 days in cauliflower, in x and 1.25 x dose, respectively. Dissipation of tolfenpyrad followed first-order kinetics with DT50 of 0.59 and 0.54 days in brinjal and 0.36 and 0.34 in cauliflower, at respective doses. The initial deposits of emamectin benzoate were below LOQ in brinjal, while in cauliflower the initial deposits were 0.01 and 0.02 mg kg−1 at x and 1.25 x dose, respectively that reached below LOQ at 1 day in both the dosages. Dietary risk assessment in children and adults under rural and urban conditions showed that recommended dosages of tolfenpyrad and emamectin benzoate do not pose any dietary risks to the consumers.