Search Results (106)

Acalitus simplex is an eriophyoid mite pest of the ornamental plant Ruellia simplex. Acalitus simplex compromises the esthetics of R. simplex by inducing erinea formation. Management practices for A. simplex are currently lacking. This study assessed the potential of commercial biorational (citric acid, potassium salt of fatty acids, garlic, thyme, and mineral oil) and conventional (abamectin, fenpyroximate, bifenthrin, spiromesifen) pesticides under laboratory conditions, using two types of spray applications: (A) curative, after erinea formation, and (B) prophylactic, before erinea formation. In the curative application, abamectin, garlic oil, and mineral oil were most effective; in the prophylactic application, abamectin and mineral oil showed the highest efficacies. Abamectin and mineral oil were further tested under greenhouse conditions. Both treatments effectively controlled A. simplex by preventing erinea formation over a four-week post-application period, regardless of the application type. At the end of the experiment, mites were extracted from R. simplex plants. In the curative application, significantly fewer mites were extracted from abamectin and mineral oil treatments than in the control. In the prophylactic application, mites were absent in abamectin and mineral oil treatments but present in the control. Abamectin and mineral oil can be used to manage A. simplex in landscapes. Full article

Spalangia endius Walker, a pupal parasitoid of the alien invasive pest Zeugodacus cucurbitae (Coquillett), causes 33% host mortality. This study assessed whether combining S. endius with insecticides (abamectin, thiamethoxam, nitenpyram, emamectin benzoate, or beta-cypermethrin)—all effective against Z. cucurbitae—could enhance control efficacy. Among these, abamectin was the least toxic to adult S. endius. Surface contact treatments with 12 and 15 mg a.i./kg of abamectin did not significantly increase S. endius mortality. However, mixing 12 mg a.i./kg of abamectin into a honey solution to encourage ingestion decreased the survival, parasitism, and fecundity of S. endius. In olfactometer assays, S. endius adults avoided abamectin-treated host pupae, though prior exposure to abamectin mitigated this avoidance. The timing of abamectin soil application relative to host pupation and S. endius release affects host mortality. The most effective timing is spraying abamectin before host pupation (to expose Z. cucurbitae larvae) and then releasing S. endius. Field trials confirmed that combining abamectin (12 mg a.i./kg) with S. endius increased host mortality more than either treatment alone. In conclusion, abamectin (12 mg a.i./kg) is a suitable insecticide for combination with S. endius to control Z. cucurbitae. The application sequence should be spraying abamectin before hosts pupate and, only after that, releasing the parasitoid. Full article

Thrips parvispinus (Karny) is an invasive pest of vegetable and ornamentals in the United States. To support ornamental growers to control T. parvispinus infestations, we tested seven conventional (spinosad, chlorfenapyr, sulfoxaflor–spinetoram, pyridalyl, tolfenpyrad, abamectin, and cyclaniliprole–flonicamid) and two biorational insecticides (mineral oil and sesame oil) under greenhouse conditions on mandevilla (Mandevilla splendens) and gardenia (Gardenia jasminoides), primary T. parvispinus ornamental hosts. Two insecticide applications were performed: a curative, treating an existing infestation, and a prophylactic, treating a plant prior to the thrips release. In the curative application, ten larvae and ten adults were released two weeks prior to treatment. Three leaves from the upper, middle, and lower canopy were collected 24 h, 7-, and 14-days post-treatment to assess thrips mortality. In the prophylactic application, plants were first sprayed with insecticides, and thrips were introduced 24 h later, but followed the same sampling method. In mandevilla, chlorfenapyr, abamectin, and spinosad caused the highest thrips mortality in both application types. Among horticultural oils, mineral oil and sesame oil increased mortality in prophylactic applications only. In gardenia, neither curative nor prophylactic applications of these products led to significant thrips mortality, and the possible reasons and recommendations for best thrips management are presented. Full article

The bird cherry-oat aphid Rhopalosiphum padi (L.) poses a significant threat to wheat production, resulting in substantial yield reductions. Abamectin and acetamiprid are frequently utilized for management. This study assessed the sublethal effects of abamectin and acetamiprid on R. padi through life table analysis and enzyme activity assays. At 24 h, the LC₁₀ and LC₃₀ values for abamectin to R. padi were 0.063 mg/L and 0.252 mg/L, respectively, while, for acetamiprid, the corresponding values were 0.065 and 0.293 mg/L. The results indicated that exposure to sublethal concentrations of abamectin (AB-LC₁₀) extended the longevity of R. padi F₀ generation, while acetamiprid (AC-LC₁₀ and AC-LC₃₀) decreased it. Furthermore, the fecundity of the F₀ generation was significantly reduced following exposure to AB-LC₃₀, AC-LC₁₀ and AC-LC₃₀. In the F₁ generation, exposure to sublethal concentrations of acetamiprid negatively impacted on R. padi, as evidenced by a significant reduction in longevity; fecundity and population parameters (R₀, r, λ, s_xj, l_x, l_xm_x, v_xj and e_xj). Conversely, sublethal concentrations of abamectin did not significantly affect these parameters. Additionally, population projections revealed a significantly smaller total population size of R. padi in the acetamiprid-exposed group compared to both the abamectin-exposed and control groups. Except these population-level effects, the activities of detoxification enzymes, including cytochrome P450 monooxygenases (P450), glutathione S-transferases (GST) and carboxylesterases (CarE), changed differently after treatments. These results suggest that sublethal concentrations of acetamiprid, but not abamectin, significantly inhibit the population growth of R. padi. These insights are crucial for R. padi control and facilitate the development of effective control strategies that take into account these sublethal effects in integrated pest management strategies targeting R. padi. Full article

In mountainous citrus orchards, the application of conventional ground sprayers for the control of citrus red mite (Panonychus citri) is often constrained by complex terrain and low operational efficiency. The Unmanned Aerial Spraying System (UASS), due to its low-altitude, low-volume, and high-maneuverability characteristics, has emerged as a promising alternative for pest management in such challenging environments. To evaluate the spray performance and field efficacy of different UASS types in controlling P. citri, five representative UASS models (JX25, DP, T1000, E-A2021, and T20), four mainstream pesticide formulations, and four novel tank-mix adjuvants were systematically assessed in a field experiment conducted in a typical hilly citrus orchard. The results showed that T20 delivered the best overall spray deposition, with upper canopy coverage reaching 10.63%, a deposition of 3.01 μg/cm², and the highest pesticide utilization (43.2%). E-A2021, equipped with a centrifugal nozzle, produced the finest droplets and highest droplet density (120.3–151.4 deposits/cm²), but its deposition and coverage were lowest due to drift. Nonetheless, it exhibited superior penetration (dIPR 72.3%, dDPR 73.5%), facilitating internal canopy coverage. T1000, operating at higher flight parameters, had the weakest deposition. Formulation type had a limited impact, with microemulsions (MEs) outperforming emulsifiable concentrates (ECs) and suspension concentrates (SCs). All adjuvants improved spray metrics, especially Yimanchu and Silwet, which enhanced pesticide utilization to 46.8% and 46.4% for E-A2021 and DP, respectively. Adjuvant use increased utilization by 4.6–11.9%, but also raised ground losses by 1.5–4.2%, except for Yimanchu, which reduced ground loss by 2.3%. In terms of control effect, the rapid efficacy (1–7 days after application, DAA) of UASS spraying was slightly lower than that of ground sprayers—electric spray gun (ESG), while its residual efficacy (14–25 DAA) was slightly higher. The addition of adjuvants improved both rapid and residual efficacy, making it comparable to or even better than ESG. E-A2021 with 5% abamectin·etoxazole ME (5A·E) and Yimanchu achieved 97.4% efficacy at 25 DAA. Among UASSs, T20 showed the rapid control, while E-A2021 outperformed JX25 and T1000 due to finer droplets effectively targeting P. citri. In residual control (14–25 DAA), JX25 with 45% bifenazate·etoxazole SC (45B·E) was most effective, followed by T20. 5A·E and 45B·E showed better residual efficacy than abamectin-based formulations, which declined more rapidly. Adjuvants significantly extended control duration, with Yimanchu performing best. This study demonstrates that with optimized spraying parameters, nozzle types, and adjuvants, UASSs can match or surpass ground spraying in P. citri control in hilly citrus orchards, providing valuable guidance for precision pesticide application in complex terrain. Full article

Integrated rice–fish farming, crucial for sustainable agriculture, relies on the judicious use of pesticide. This study evaluates the toxicity of six common rice-field pesticides on Procypris merus (rice flower carp), a key species in these systems. We conducted acute and chronic toxicity tests, assessing survival, growth, oxidative stress (SOD, CAT, MDA, 8-OHdG), and neurotoxicity (AChE). Results revealed a spectrum of toxicity: abamectin and trifloxystrobin were highly toxic; pretilachlor was moderately so; and glufosinate-ammonium, triflumezopyrim, and thiazole zinc were low. Notably, triflumezopyrim induced significant oxidative stress and DNA damage, while all three low-toxicity pesticides inhibited AChE activity, indicating potential neurotoxicity. Despite these effects, all observed toxicities were reversible within 7–14 days. Considering that the tested concentrations exceeded typical field application rates, glufosinate-ammonium, triflumezopyrim, and thiazole zinc are deemed relatively safe for P. merus at recommended dosages. Our findings provide critical insights for optimizing pesticide selection in rice–fish farming, balancing pest control with ecological safety, thereby informing sustainable agricultural practices. Full article

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a super pest that seriously endangers the development of the agricultural economy worldwide. To prevent and control B. tabaci, insecticides have been used for many years, which has inevitably led to increased tolerance to chemical agents. To elucidate the development of field resistance and more scientifically and efficiently control B. tabaci, in December 2024, we conducted bioassays on B. tabaci on soybeans in Suzhou, Anhui Province, using 14 insecticides. These fourteen insecticides, namely, abamectin, spinetoram, thiamethoxam, flupyradifurone, imidacloprid, dinotefuran, acetamiprid, thiacloprid, nitenpyram, bifenthrin, deltamethrin, pyridaben, flonicamid, and emamectin benzoate, have multiple action sites and have all shown good control effects on B. tabaci. The results revealed that B. tabaci has developed high resistance to many insecticides and that some insecticides have even tended to fail, but B. tabaci is still sensitive to a small number of insecticides. Different biotypes of B. tabaci differ significantly in terms of insecticide resistance. We determined that the population of B. tabaci on soybean in Suzhou was the MED (Q) biotype. It carried the TYLCV virus, with a virus carrying rate of 60%, but did not carry ToCV or CCYV. Full article

To identify the species of Collembola that harm Morchella and to screen for pesticides that are effective in controlling these pests with minimal inhibition of mycelial growth, a five-point sampling method was used to investigate the population of Collembola and its damaging effects on Morchella and to analyze its spatial distribution in the soil. The indoor control efficacy of ten insecticides was determined using the mushroom disc immersion method and the pesticide film method. The most effective insecticides were then selected for field testing. The effect of the best-performing field pesticides on the mycelial growth of Morchella was measured using the Petri dish mycelial growth rate method, and pesticide residues were detected using chromatography. The survey revealed that in three Morchella greenhouses, the average Collembola population was 220,333 individuals/m³. The spatial distribution of Collembola was uniform. The collected Collembola specimens were identified as Oligaphorura ursi from the family Onychiuridae. Through the lab and field screening of pesticides, it was found that 40% phoxim EC, 1.8% abamectin EC, 2.5% lambda-cyhalothrin EW, and 4.5% beta-cypermethrin EC had the best efficacy. Meanwhile, residues of these four pesticides were not detected. Mycelial growth inhibition experiments showed that 2.5% lambda-cyhalothrin EW, 1.8% abamectin EC, and 4.5% beta-cypermethrin EC exhibit low inhibition of mycelial growth and can be used as control pesticides for Collembola on Morchella, providing a technical reference for the green pesticide control of Collembola on Morchella in the study region. Full article

Stethorus punctillum Weise, a predatory beetle attacking phytophagous mites in northwest China, remains underutilized for biological control. Current over-reliance on synthetic acaricides necessitates evaluation of their non-target effects on this predator, particularly their safety and sublethal impacts. Here, we assessed the acute toxicity of four acaricides to S. punctillum in laboratory bioassays and then focused on sublethal impacts of abamectin on adult predation efficiency and lifespan. Based on the LC₅₀ values, the acute toxicities of the four acaricides tested against S. punctillum larvae and adults both ranked as follows (from greatest to least): abamectin > pyridaben > spirotetramat > petroleum oil. All acaricides exhibited selective toxicity (STR: 2.16–182.49) with moderate to low risk (SF: 0.46–8.71). Notably, petroleum oil, despite showing the lowest acute toxicity to S. punctillum, posed the highest risk to larvae (SF: 0.46–0.77). Abamectin exposures at LC₂₀ or LC₅₀ significantly compromised S. punctillum adults, prolonging prey handling time (females: 33–100%; males: 40%), reducing maximum daily predation (females: 25–50%; males: 29%), and shortening adult lifespan (females: 2.34–3.17 days; males: 3.95–5.08 days). This study assessed the safety of four commonly used acaricides for S. punctillum, revealing abamectin-induced impairments to key biological traits. Our findings offer critical insights for risk-aware acaricide selection and integrated spider mite management strategies in agroecosystems in northwest China. Full article

New intervention methods and product formulations are needed to better control pyrethroid-resistant Aedes aegypti populations and mitigate the risk of mosquito-borne disease. ReMoa Tri is a novel adulticidal space spray that utilizes a different mode of action than the commonly used adulticides: pyrethroids and organophosphates. As a triple-action space spray, ReMoa Tri combines three components: Fenpropathrin, a mixed-type I/II pyrethroid; abamectin, a macrocyclic lactone; and C8910, a patented fatty acid chain. Prior studies performed by Collier Mosquito Control District showed that ReMoa Tri is effective at controlling type I pyrethroid-resistant Ae. aegypti mosquitoes. To further validate these results and the performance of ReMoa Tri, we conducted a semi-field evaluation using ground and aerial ULV (ultra-low volume) applications with field-caught deltamethrin-resistant Ae. aegypti and a susceptible Ae. aegypti laboratory strain. Ground evaluations tested ReMoa Tri and a type II pyrethroid-based product, DeltaGard. While ReMoa Tri was equally effective against Collier’s deltamethrin-resistant Ae. aegypti and the susceptible laboratory strain, DeltaGard was effective against both strains, with reduced efficacy at farther distances. Similarly, aerial evaluations also showed that ReMoa Tri was equally effective against Collier’s deltamethrin-resistant Ae. aegypti strain and susceptible laboratory strain. This study further confirms ReMoa Tri’s potential as an effective alternative to pyrethroid-based adulticides, both in ground and aerial applications, for managing pyrethroid-resistant Ae. aegypti. Full article

Tuta absoluta (Meyrick) is an important invasive pest that seriously affects the yield and quality of tomatoes. In this study, based on the previously obtained transcriptome data, a total of 25,123 SSR loci and 332,537 SNP loci were identified. The identified SSRs had occurrence and appearance frequencies of 28.62% and 40.60%, respectively. SSRs with a length equal to or greater than 12 bp constituted 58.25% of the total SSR loci. Through the analysis of GO, COG annotations, and the KEGG pathway database, it was revealed that the majority of SSR-transcripts were involved in fundamental cellular metabolic functions. In addition, the frequency of SNP occurrence was approximately one SNP locus per 175 base pairs (bp), and the transition type was the main variant type. The functional annotations of SNP-transcripts were primarily concentrated in biological synthesis pathways such as peroxisome, RNA transport, carbon metabolism, and protein processing in the endoplasmic reticulum. These synthesis pathways are involved in the detoxification mechanism of T. absoluta and contribute to its enhanced survival under pesticide susceptibility. These findings provide valuable data for constructing genetic maps, assessing genetic diversity, and determining functional orientation in insects, and they also provide basic data for the molecular mechanism of T. absoluta ‘s response to pesticide susceptibility. Full article

The two-spotted spider mite (Tetranychus urticae) is a highly destructive and economically significant pest in agricultural, horticultural, and ornamental agroecosystems worldwide, including hop (Humulus lupulus) and mint (Mentha spp.) fields in the Pacific Northwest (PNW) region of the United States. Repeated acaricide applications and rotations have led to widespread resistance, resulting in control failures. In this study, we investigated the mechanisms of resistance to four different acaricides (bifenthrin, bifenazate, etoxazole, and abamectin) across 23 field-collected TSSM populations by integrating diagnostic bioassays, genetic screening for resistance-associated mutations, structural modeling, and molecular docking. Several kdr mutations and mutation combinations were detected in TuVGSC across all tested populations. The G132A in Tucytb was identified in 68.75% of hop and 40% of mint TSSM populations, while the I1017F in TuCHS 1 was found in 94% of hop and 100% of mint populations. Structural analysis revealed key interactions between acaricides and target proteins in both wild-type and mutant variants, providing novel insights into the functional impacts of these mutations. Our findings enhance the understanding of TSSM adaptation to acaricides among different crops, supporting the development of more effective resistance management strategies to mitigate economic losses in hops, mint, and other crop production. Full article

The growing demand for agricultural products has led to the misuse of pesticides, resulting in the use of higher concentrations of these substances. This has led to an increase in toxicity imposed on other beneficial organisms and to the bioaccumulation of toxic pesticide concentrations in the bodies of both pests and non-target organisms, as well as in their end users, including humans. In this study, the neurotoxic potential of the commonly used pesticides abamectin (an insecticide) and boscalid (a fungicide) was evaluated. Both in vitro and in silico studies showed that human butyrylcholinesterase is not a target for abamectins B1A and B1B. Boscalid showed a modest Glide score (−28.8 kJ/mol) and a considerably higher IC₅₀ (308.8 µM) against human butyrylcholinesterase than the approved inhibitor (2-((1-(benzenesulfonyl)-1H-indol-4-yl)oxy)ethyl)(benzyl)amine (IC₅₀ = 0.473 µM). However, due to its non-mutagenicity and low toxicity, structural analogues of boscalid might be considered as candidates for the symptomatic treatment of Alzheimer’s disease. Molecular dynamics simulations over 100 ns confirmed the stability of boscalid within the active site of butyrylcholinesterase, where it maintained key interactions with catalytic residues such as Trp82 and His438. These findings highlight its potential as a starting point for structure-based drug design strategies aimed at optimizing cholinesterase inhibitors with improved pharmacokinetic properties. According to absorption, distribution, metabolism, elimination, and toxicity studies, boscalid is orally active, which cannot be attributed to abamectins B1A and B1B. Full article

Glutathione S-transferase (GST) is a class of detoxifying enzymes in the second stage of insect metabolism and plays a key role in insecticide resistance. In this study, based on the transcriptome sequences of S. frugiperda, the full-length cDNA of SfGSTD1 was cloned and characterized. The temporal and spatial expression pattern showed that SfGSTD1 was highly expressed in Malpighian tubules, which are key excretion organs. Knocking down SfGSTD1 reduced S. frugiperd tolerance to abamectin and beta-cypermethrin. The overexpression of SfGSTD1 enhanced the viability of Sf9 cell under abamectin and beta-cypermethrin treatment. Furthermore, SfGSTD1 was overexpressed in Drosophila melanogaster using the GAL4/UAS binary expression system, and this overexpression strain was also less susceptible to abamectin and beta-cypermethrin. The enzyme activity of recombinant SfGSTD1 could also be significantly inhibited by abamectin and beta-cypermethrin. Taken together, our findings indicate that SfGSTD1 might be involved in the tolerance of abamectin and beta-cypermethrin in S. frugiperda. And these results provide theoretical foundations for understanding the resistance mechanism of S. frugiperda to abamectin and beta-cypermethrin. Full article

Fluxametamide, an innovative isoxazoline insecticide, acts as an antagonist of γ-aminobutyric acid-gated chloride channels. Its distinct mode of action sets it apart, lacking known cross-resistance with current insecticides. This positions fluxametamide as a promising tool for addressing insecticide resistance in Lepidoptera, thysanoptera, coleoptera, and diptera pest insects. To develop and implement successful resistance management strategies, it is crucial to establish the baseline susceptibility to this insecticide before it is registered and widely used in China. In this study, we assessed the baseline susceptibility of two widespread lepidopteran pest species, Plutella xylostella and Spodoptera exigua, to fluxametamide. The insecticide exhibited remarkably high efficacy against populations of the two lepidopteran species sampled in their primary distribution areas in China. For P. xylostella and S. exigua, the median lethal concentrations (LC₅₀) ranged between 0.040 and 0.247 mg/L, and 0.211 and 0.761 mg/L, respectively. Among populations, there was a relative low variability in susceptibility to fluxametamide, showing a 6.18-fold difference for P. xylostella and 3.61-fold for S. exigua. The suggested diagnostic concentrations for P. xylostella and S. exigua were 10 and 15 mg/L, respectively. Fluxametamide exhibited high toxicity to the selected resistant strains, which displayed strong resistance to abamectin, emamectin benzoate, and deltamethrin. No cross-resistance to fluxametamide was detected in the laboratory diamide-resistant strain. Our findings offer essential insights for crafting successful resistance management initiatives to maintain the effectiveness of fluxametamide against these significant pests. Full article