The potential of synergists to improve insecticide efficacy and strengthen insecticide resistance management (IRM) strategies is highlighted and Cytochrome P450 monooxygenases and carboxyl esterases appear more influential in BBPL while glutathione S-transferases are more significant in BPPL.
Abstract
Insecticide efficacy against the maize fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is closely linked to metabolic detoxification processes that can be influenced by the use of synergists. This study assessed the effect of five selected synergists on the toxicity of five commonly used insecticides against third-instar larvae collected from 2 locations in Odisha, namely Bhubaneswar and Bhawanipatna, under laboratory conditions. In the Bhubaneswar population (BBPL), lambda-cyhalothrin exhibited the highest synergism with piperonyl butoxide (PBO) and N-(propargyloxy) phthalimide with synergistic ratios (SR) of 6.50 and 4.41 respectively. Acephate recorded the highest synergism with triphenyl phosphate (TPP) (SR = 5.85). Diethyl maleate (DEM) showed greater synergism with emamectin benzoate (SR = 3.91) and spinetoram responded notably to PBO (SR = 4.20). In contrast, the Bhawanipatna population (BPPL) showed a stronger and more consistent response to DEM with all five insecticides, with SR values of 6.71 for lambda-cyhalothrin, 6.20 for acephate, 5.10 for spinetoram and 4.76 for emamectin benzoate. Chlorantraniliprole exhibited comparatively lower synergistic responses with most synergists, although DEM produced a substantially higher synergistic ratio in BPPL (SR = 4.39). The least effective synergist was 5-nitrouracil (1.25–1.72) in both populations, indicating a minimal role of uridine diphosphate glycosyltransferases (UGTs) mediated detoxification pathways. The difference in synergistic response between populations suggests involvement of different detoxification enzymes in both populations. Cytochrome P450 monooxygenases and carboxyl esterases appear more influential in BBPL while glutathione S-transferases (GST) are more significant in BPPL. These findings highlight the potential of synergists to improve insecticide efficacy and strengthen insecticide resistance management (IRM) strategies.
Spodoptera frugiperda, known as the fall armyworm (FAW), is a polyphagous pest that causes huge economic losses in different agricultural regions of the world. Its control is challenging due to its widespread resistance to conventional insecticides and Bt events. This study aimed to assess the lethal toxicity and growth-inhibitory effects of eight acetone-derived monoketone curcuminoids (MKCs) on S. frugiperda larvae. MKCs were synthesized by Claisen-Schmidt condensation between acetone and aromatic aldehydes in a basic medium and tested against FAW larvae at a concentration of 250 mg kg-1 (dietary exposure) over 7 days. None of the tested compounds showed a significant lethal toxicity to FAW. However, halogenated MKCs derivatives 4 ((1E,4E)-1,5-bis(4-fluorophenyl)penta-1,4-dien-3-one) and 5 ((1E,4E)-1,5-bis(4-chlorophenyl)penta-1,4-dien-3-one) exhibited sublethal effects, reducing larval weight by 59% and 55%, respectively, compared to the negative control. These results indicated that the halogenation of MKCs may be a promising strategy to be exploited in the search for novel bioactive compounds to manage FAW in agricultural food production systems.
Keywords: Claisen-Schmidt condensation; fall armyworm; halogenated compounds; monoketone curcuminoids
Larissa Costa de Oliveira, Y. R. Robles, Murilo Norberto Pereira et al.· Multi-Science Journal· 0 citations
Substantial resistance to several frequently used insecticides, particularly buprofezin and imidacloprid, is demonstrated, accompanied by enhanced detoxification enzyme activity and altered biological performance within integrated brown planthopper management programmes.
V. Ratnakar, V. J. Lakshmi, Y. Swathi et al.· Journal of Advances in Biolo...· 0 citations
The agricultural industry largely relies on conventional pesticides to maintain healthy, pest-free crops. Application of conventional insecticides is the go-to method for cultivating important food crops, such as corn and sorghum, free of Spodoptera frugiperda (fall armyworm) infestations. However, conventional insecticides have purported negative environmental and health impacts. Natural plant extracts, such as essential oils, are viewed as a promising alternative to conventional insecticides. In the current study, Dysphania ambrosioides (epazote) essential oil was embedded into an artificial diet and fed at two different concentrations to fall armyworms during a 10-day period. Final weights of the 5% epazote treatment group were statistically less (F6343 = 136.2 p < 0.001) than control groups. The 5% epazote treatment group also experienced the highest mortality rate (62%) of any treatment group (X2 = 831.4, DF = 6, p < 0.001). Findings suggest that epazote essential oil has potential as an effective, natural insecticidal ingredient. This research is of importance to the fields of agronomy and health sciences.
Tyler M. Wilson, I. Lykken, Christopher R. Bowerbank et al.· Agrochemicals· 0 citations
Fall armyworm, Spodoptera frugiperda, is a maize pest whose management remains dependent on synthetic insecticides. This study compared three organophosphate insecticides against third-instar S. frugiperda larvae. Chlorpyrifos, profenofos, and diazinon were evaluated at 5%, 20%, 50%, 75%, and 95% of the maximum label dose using a factorial completely randomized design with three replications of six larvae. Mortality was recorded for 168 h and corrected using Abbott’s formula based on pooled control mortality. Insecticide formulation significantly affected mortality (F₂,₃₀ = 39.06, P < 0.001), whereas concentration (F₄,₃₀ = 0.57, P = 0.687) and the insecticide × concentration interaction (F₈,₃₀ = 1.62, P = 0.162) were not significant. Across concentrations, profenofos and diazinon caused mean mortalities of 90.4% and 93.2%, respectively, and both were more effective than chlorpyrifos, which caused 32.2% mortality. Exploratory probit analysis estimated LC₅₀ values of 2.01% for profenofos and 0.71% for diazinon, but both were below the lowest concentration and had wide confidence intervals. Chlorpyrifos LC values were not estimable because its concentration–mortality slope was negative and non-significant. At 95% of the label dose, profenofos reached 50% corrected mortality within 24 h and diazinon within 48 h, whereas chlorpyrifos did not reach this threshold within 168 h. Profenofos and diazinon showed comparably high efficacy and outperformed chlorpyrifos.
Najma Ayu Koeswari, J. E. Rumbiak, Andree Saylendra et al.· Jurnal Ilmiah Pertanian· 0 citations
In this study, pyridaben LC values, resistance ratios, detoxification enzyme activities, synergism tests, and the H92R target-site mutation were investigated in T. urticae populations collected from apple orchards, providing important insights into the biochemical and molecular mechanisms underlying pyridaben resistance and the genetic basis of resistance evolution.
Gizem Berber-Tortop, H. Tosun, C. Ikten et al.· Experimental & applied acaro...· 0 citations
Spodoptera frugiperda (J.E. Smith) is a destructive invasive pest that poses a serious threat to maize production, necessitating the development of sustainable management strategies. The present study evaluated the efficacy of integrating selective insecticides with Metarhizium anisopliae for the management of fall armyworm under field conditions. Field experiments were conducted at two locations in South Gujarat, India, during the Rabi 2025–26 season using novaluron 5.25 + emamectin benzoate 0.9 SC and thiamethoxam 12.60 + lambda-cyhalothrin 9.50 SC applied alone and in combination with M. anisopliae, along with M. anisopliae alone and an untreated control. Repeated-measures mixed-effects analysis revealed significant treatment effects on plant infestation, leaf damage, cob infestation and cob yield. Among the evaluated treatments, novaluron 5.25 + emamectin benzoate 0.9 SC integrated with M. anisopliae recorded the lowest plant infestation (32.92%), leaf damage score (2.70) and cob infestation (11.01%), and produced the highest cob yield (13.21 t ha⁻¹), representing a 40.53% increase over the untreated control. Although statistically comparable with novaluron 5.25 + emamectin benzoate 0.9 SC applied alone for most parameters, the integrated treatment consistently showed numerically superior performance. In contrast, M. anisopliae applied alone provided only moderate suppression of fall armyworm and lower yield protection than insecticide-based treatments. These findings demonstrate that integrating M. anisopliae with selective insecticides improves fall armyworm management and maize productivity, highlighting its potential as an effective component of integrated pest management (IPM) for sustainable maize production.
Nisarg Panchal, M. Siddhapara, V. M. Khimani et al.· Uttar Pradesh Journal of Zoo...· 0 citations
