Search Results (31)

Cyclaniliprole is a novel third-generation anthranilic diamide insecticide which has broad-spectrum efficacy against various pests, including aphids. Rhopalosiphum padi and Schizaphis graminum are the two primary aphid species that infest wheat crops. This investigation evaluates cyclaniliprole’s acute toxicity and sublethal and transgenerational effects on both aphid species. The acute toxicity assessment revealed obvious insecticidal activity, with 24 h LC₅₀ values of 38.56 mg/L for R. padi and 33.71 mg/L for S. graminum. Sublethal exposure (LC₁₅ and LC₃₅ in R. padi; LC₃₅ in S. graminum) significantly reduced adult longevity and fecundity in the F₀ generation. In the F₁ generation, cyclaniliprole at LC₃₅ significantly reduced the fourth nymph stage in R. padi, whereas at LC₁₅, it shortened the third nymph stage duration in S. graminum compared to the control. Sublethal concentrations (LC₁₅ and LC₃₅) of cyclaniliprole significantly reduced age-stage-specific survival rate (s_xj), age-specific survival rate (l_x), age-specific maternity (l_xm_x), and age-stage life expectancy (e_xj) in the F₁ generation of R. padi, while only LC₃₅ decreased l_x, l_xm_x, and e_xj in S. graminum. Additionally, LC₃₅ significantly reduced the net reproductive rate (R₀) in the F₁ generation of R. padi compared to the control. These findings suggest that cyclaniliprole exhibit notable acute toxicity against both aphid species and that sublethal concentrations adversely affected the F₀ generation, with no observed hormetic effects in the F₁ generations of R. padi and S. graminum. The findings offer valuable insights for assessing the comprehensive insecticidal potential of cyclaniliprole. Full article

Chlorantraniliprole, serving as a substitute for traditional insecticide, has been widely utilized in controlling lepidopteran pests. Loxostege sticticalis (Lepidoptera: Crambidae) is a polyphagous insect and poses a significant threat as a migratory insect. This study investigated the life history traits of a field-collected population in response to chlorantraniliprole exposure based on an age-stage, two-sex life table. After treating the third-instar larvae of L. sticticalis with three different doses of chlorantraniliprole, namely LC₁₀, LC₂₅, and LC₅₀, the survival, development, and fecundity of L. sticticalis were affected significantly in a dose-dependent manner. Chlorantraniliprole at doses of LC₁₀, LC₂₅, and LC₅₀ prolonged the average generation time (T) compared to the control group. The net reproductive rate (R₀) and intrinsic growth rate (r) were significantly higher in the LC₁₀ group but significantly lower in the LC₂₅ and LC₅₀ groups. Chlorantraniliprole used at a dose of LC₁₀ was shown to increase the finite growth rate (λ), while it decreased λ at doses of LC₂₅ and LC₅₀. These results suggested that chlorantraniliprole induces hormetic effects by enhancing fecundity and reproductive potential at lower sublethal concentration (LC₁₀), while reducing the reproductive output at higher doses (LC₂₅ and LC₅₀). Our results provide useful information for developing management strategies for L. sticticalis involving the use of chlorantraniliprole. Full article

The red spider mite, Tetranychus macfarlanei, is a serious pest of many cultivated crops in Bangladesh and other East-Asian and South-East Asian countries, in the Afrotropical, Oriental, and Palearctic regions. Sublethal concentration of pesticides, such as LC₁₅ and LC₃₀ (the concentrations that result in 15 and 30 percent lethality, respectively) impact reproduction, behavior, development, and physiology. This study assessed the effects of different concentrations of spirotetramat, an insecticide that disrupts lipid production, on the biological traits of T. macfarlanei. The LC₁₅, LC₃₀, LC₅₀, and LC₉₀ values were 2.16, 6.57, 20.54, and 332.81 mg·L⁻¹, respectively. Sublethal concentrations (LC₁₅ and LC₃₀) slightly reduced female fecundity but did not significantly affect development duration, pre-oviposition, oviposition period, or longevity compared to the untreated control group. Life table parameters differed between the treated and control groups, with significant reductions in the intrinsic rate of increase (r), the net reproductive rate (R₀), and the finite rate of increase (λ) for LC₁₅ and LC₃₀. LC₁₅ and LC₃₀ had negative effects on the intrinsic rate of increase for females. This study demonstrated that lower lethal concentrations of spirotetramat compromised survivability and negatively impacted the life-table parameters of subsequent generations of T. macfarlanei. These findings highlight the importance of sublethal effects in pest control, offering valuable insights for developing more effective and sustainable integrated pest management strategies. Full article

The tobacco whitefly, Bemisia tabaci MEAM1, is a destructive pest that damages plants by sucking plant juice and transmitting viruses. B. tabaci insecticide resistance contributes to population resurgence, and new insecticides are continually needed. Flonicamid and afidopyropen are selective pesticides with high insecticidal activity against piercing–sucking pests and safety to non-target species. We determined the toxicity of flonicamid and afidopyropen to B. tabaci, investigated the sublethal effects on life parameters, and studied physiological responses to them. Flonicamid and afidopyropen were highly toxic to B. tabaci, with LC₅₀ values of 12.795 mg/L (afidopyropen) and 25.359 mg/L (flonicamid) to nymphs and 4.711 mg/L (afidopyropen) and 11.050 mg/L (flonicamid) to adults. Sublethal concentrations (LC₁₀ and LC₂₀) reduced the longevity and fecundity of the B. tabaci F0 generation. Transgenerational effects were caused by exposure to sublethal concentrations of flonicamid and afidopyropen. Nymph mortality increased, development was delayed, fecundity decreased, and adult longevity was shortened. Population parameters such as the intrinsic rate of growth (r), net reproductive rate (R₀), and finite rate of growth (λ) were significantly decreased compared to the control. The activity of detoxifying enzymes, such as GSTs and P450, were induced by flonicamid and afidopyropen at 72 h, while CarE was inhibited. The expression levels of eleven P450 genes and four GST genes were significantly higher than in the control. In conclusion, flonicamid and afidopyropen have excellent acute toxicity and continuous control effects on B. tabaci. Higher GST and P450 activities and gene expression levels may play important roles in the detoxification metabolic process. Full article

Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) is a highly dispersive, polyphagous insect pest that severely defoliates crops. Excessive reliance on synthetic insecticides leads to ecological pollution and resistance development, urging scientists to probe eco-friendly biopesticides. Here, we explore the virulence of an entomopathogenic fungus, Beauveria bassiana, against S. exigua, resulting in 88% larval mortality. Using an age–stage, two-sex life table, we evaluated the lethal and sublethal effects of B. bassiana on the demographic parameters of S. exigua, including survival, development, and reproduction. Sublethal (LC₂₀) and lethal concentrations (LC₅₀) of B. bassiana impacted the parental generation (F₀), with these effects further influencing the demographic parameters of the first filial generation (F₁). The infected F₁ offsprings showed a reduced intrinsic rate of increase (r), mean generation time (T), and net reproduction rate (R₀). Larval developmental duration varied significantly between the control (10.98 d) and treated groups (LC₂₀: 10.42; LC₅₀: 9.37 d). Adults in the treated groups had significantly reduced lifespans (M: 8.22; F: 7.32 d) than the control (M: 10.00; F: 8.22 d). Reduced fecundity was observed in the B. bassiana-infected groups (LC₂₀: 313.45; LC₅₀: 223.92 eggs/female) compared to the control (359.55 eggs/female). A biochemical assay revealed elevated levels of detoxification enzymes (esterases, glutathione S-transferases, and acetylcholinesterase) in the F₀ generation after B. bassiana infection. However, the enzymatic activity remained non-significant in the F₁ generation likely due to the lack of direct fungal exposure. Our findings highlight the enduring effects of B. bassiana on the biological parameters and population dynamics of S. exigua, stressing its use in eco-friendly management programs. Full article

The stink bug, Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), is a highly destructive pest that significantly damages legume crops in East and South Asia. Neonicotinoid insecticides containing thiamethoxam are widely used to control R. pedestris in soybean fields. However, the current knowledge on the impact of different thiamethoxam concentrations on R. pedestris growth and reproduction is lacking and insufficient. The present study investigated the effects of thiamethoxam on the biological traits of R. pedestris after treatment with LC₁₀ (19.8 mg/L), LC₂₀ (31.6 mg/L), LC₃₀ (44.2 mg/L), LC₄₀ (58.9 mg/L), and LC₅₀ (77.0 mg/L) concentrations. These five thiamethoxam concentrations (LC₁₀~LC₅₀) reduced adult longevity and fecundity in the F₁ generation females. Thiamethoxam treatment also significantly decreased the population trend index, intrinsic rate of increase, net reproductive rate, gross reproductive rate, and finite rate of increase and increased the mean generation time. These results show that thiamethoxam hinders and suppresses the development and growth of the F₁ population of R. pedestris. Thiamethoxam is recommended for spray control during peak adult emergence, as it not only has a controlling effect on the parental generation but also a negative impact on the F₁ generations. Full article

The toxicity and sublethal effects of three insecticides (spirotetramat, cyantraniliprole, and pymetrozine) on Aphis gossypii, a major agricultural pest, were investigated. The nymphal stage showed greater susceptibility than the adult stage to all the insecticides, with a difference of up to 8.9 times at the LC₅₀ of spirotetramat. The effects of sublethal concentrations (LC₁₀, LC₃₀, LC₅₀, and LC₇₀) of the insecticides on the on the developmental period, survival rate, adult longevity, fecundity, and deformity rate were compared with those of the control. Compared with the control, cyantraniliprole and pymetrozine did not significantly affect the developmental period in the parental or F₁ generation when applied at the nymphal stage at any concentration. Nonviable nymphs occurred in the F₁ generation when both nymphs and adults were treated with spirotetramat and cyantraniliprole but not in the F₂ generation. The age-specific maternity (l_xm_x) of A. gossypii treated with sublethal concentrations (LC₁₀, LC₃₀) decreased with increasing concentration. Spirotetramat at the LC₃₀ resulted in significant differences in all life table parameters (R₀, r_m, λ, T, DT) compared with those of the control. Similarly, compared with that of the control (43.8), the net reproductive rate (R₀) significantly decreased for all the insecticides except cyantraniliprole at the LC₁₀ (37.5). Therefore, this study indicated that sublethal concentrations (over the LC₃₀) of spirotetramat, cyantraniliprole, or pymetrozine might be useful for the density management of A. gossypii. Full article

In the geological research of the Moon and other celestial bodies, the identification and analysis of impact craters are crucial for understanding the geological history of these bodies. With the rapid increase in the volume of high-resolution imagery data returned from exploration missions, traditional image retrieval methods face dual challenges of efficiency and accuracy when processing lunar complex crater image data. Deep learning techniques offer a potential solution. This paper proposes an image retrieval model for lunar complex craters that integrates visual and depth features (${\mathrm{LC}}^2\mathrm{R}-\mathrm{Net}$) to overcome these difficulties. For depth feature extraction, we employ the Swin Transformer as the core architecture for feature extraction and enhance the recognition capability for key crater features by integrating the Convolutional Block Attention Module with Effective Channel Attention (CBAMwithECA). Furthermore, a triplet loss function is introduced to generate highly discriminative image embeddings, further optimizing the embedding space for similarity retrieval. In terms of visual feature extraction, we utilize Local Binary Patterns (LBP) and Hu moments to extract the texture and shape features of crater images. By performing a weighted fusion of these features and utilizing Principal Component Analysis (PCA) for dimensionality reduction, we effectively combine visual and depth features and optimize retrieval efficiency. Finally, cosine similarity is used to calculate the similarity between query images and images in the database, returning the most similar images as retrieval results. Validation experiments conducted on the lunar complex impact crater dataset constructed in this article demonstrate that ${\mathrm{LC}}^2\mathrm{R}-\mathrm{Net}$ achieves a retrieval precision of 83.75%, showcasing superior efficiency. These experimental results confirm the advantages of ${\mathrm{LC}}^2\mathrm{R}-\mathrm{Net}$ in handling the task of lunar complex impact crater image retrieval. Full article

Thiamethoxam, a second-generation neonicotinoid insecticide is widely used for controlling sap-sucking insect pests including Rhopalosiphum padi. The current study aimed to investigate the life-history parameters and feeding behavior of R. padi following treatments with sublethal concentrations of thiamethoxam. The lethal concentration 50 (LC₅₀) value of thiamethoxam against adult R. padi was 11.458 mg L⁻¹ after 48 h exposure. The sublethal concentrations of thiamethoxam (LC₅ and LC₁₀) significantly decreased the adult longevity, fecundity, and reproductive days in the directly exposed aphids (F₀ generation). In the progeny R. padi (F₁), the developmental durations and total prereproductive period (TPRP) were decreased while the adult longevity, fecundity, and reproductive days (RP_d) were increased at both thiamethoxam concentrations. The demographic parameters including the net reproductive rate (R₀), intrinsic rate of increase (r), and finite rate of increase (λ) were prolonged only at the LC₅ of thiamethoxam. The EPG results indicated that the sublethal concentrations of thiamethoxam increases the total duration of non-probing (Np) while reducing the total duration of E2 in directly exposed aphids (F₀). Interestingly, the E2 were significantly increased in the progeny generation (F₁) descending from previously exposed parental aphids (F₀). Overall, this study showed that thiamethoxam exhibited high toxicity against directly exposed individuals (F₀), while inducing intergenerational hormetic effects on the progeny generation (F₁) of R. padi. These findings provided crucial details about thiamethoxam-induced hormetic effects that might be useful in managing resurgences of this key pest. Full article

Aphis gossypii Glover, a widespread insect, presents a substantial danger to global agriculture. Lambda-cyhalothrin is a pyrethroid insecticide that has been widely studied for its effects on arthropods. Studies have reported that sublethal doses of insecticides can produce various consequences on arthropod reproduction. Hence, the objective of this research was to examine the potential effects of a sublethal dose of lambda-cyhalothrin (LC₃₀, 1.15 mg/L) on A. gossypii, for which we created life tables and conducted qPCR analysis. Adult longevity, fecundity, net reproductive rate (R₀), body length, width, weight, and the expression of vitellogenin (Vg) and vitellogenin receptor (VgR) genes were not significantly altered by lambda-cyhalothrin treatment at LC₃₀ concentration in the F₀ generation of A. gossypii adults. The intrinsic rate of increase (r) and finite rates of increase (λ) decreased significantly, while the mean generation time (T) increased. In addition, Vg and VgR gene expression levels were significantly higher in the F₁ and F₂ generations, whereas body length, width, and weight were notably reduced. The developmental duration, longevity, r, and λ did not differ significantly from those of the control group. Thus, the sublethal and intergenerational stimulatory effects of lambda-cyhalothrin were observed in A. gossypii, and the alterations in Vg and VgR in A. gossypii were strongly associated with sublethal effects. The results of this research offer valuable knowledge regarding the indirect impacts of lambda-cyhalothrin on A. gossypii, which can be utilized as a theoretical foundation for the prudent utilization of insecticides to combat this pest and devise strategies for managing resistance. Full article

Interest in developing novel crop protectants has increased in the recent decade due to the harmful effects of synthetic pesticides on humans and the environment. Diaphorina citri threatens the citrus industry worldwide and is the primary vector of phloem-limited bacterium (HLB). However, there is no available cure for HLB. Diaphorina citri management mainly depends on the use of synthetic insecticides, but their massive application leads to resistance in pest populations. Therefore, alternative pest management strategies are needed. Our results indicated that fewer D. citri adults settled on plants treated with AAEO than on control 48 h after release. The psyllids fed on citrus leaves treated with AAEO significantly reduced the honeydew production compared to the control. The AAEO showed potent ovicidal activity against the D. citri eggs with LC₅₀ 5.88 mg/mL. Furthermore, we also explored the fitness of D. citri on AAEO-treated and untreated Citrus sinensis by using two-sex life table tools. Our results revealed that the intrinsic rate of increase (r) was higher on untreated seedlings (0.10 d⁻¹) than those treated with an LC₂₀ concentration of AAEO (0.07 d⁻¹). Similarly, the net reproductive rate (R₀) was higher for untreated seedlings (14.21 offspring) than those treated (6.405 offspring). Furthermore, the AAEO were safer against Aphis mellifera, with LC₅₀ 35.05 mg/mL, which is relatively higher than the LC₅₀ 24.40 mg/mL values against D. citri. The results indicate that AAEO exhibits toxic and behavioral effects on D. citri, which can be a potential candidate for managing this pest. Full article

Symbiotic bacteria and hormesis in aphids are the driving forces for pesticide resistance. However, the mechanism remains unclear. In this study, the effects of imidacloprid on the population growth parameters and symbiotic bacterial communities of three successive generations of Acyrthosiphon gossypii were investigated. The bioassay results showed that imidacloprid had high toxicity to A. gossypii with an LC₅₀ of 1.46 mg·L⁻¹. The fecundity and longevity of the G0 generation of A. gossypii decreased when exposed to the LC₁₅ of imidacloprid. The net reproductive rate (R₀), intrinsic rate of increase (r_m), finite rate of increase (λ), and total reproductive rate (GRR) of G1 and G2 offspring were significantly increased, but those of the control and G3 offspring were not. In addition, sequencing data showed that the symbiotic bacteria of A. gossypii mainly belonged to Proteobacteria, with a relative abundance of 98.68%. The dominant genera of the symbiotic bacterial community were Buchnera and Arsenophonus. After treatment with the LC₁₅ of imidacloprid, the diversity and species number of bacterial communities of A. gossypii decreased for G1–G3 and the abundance of Candidatus-Hamiltonella decreased, but Buchnera increased. These results provide insight into the resistance mechanism of insecticides and the stress adaptation between symbiotic bacteria and aphids. Full article

Rice (Oryza sativa) is the most important food crop all over the world, while white-backed planthopper (WBPH), Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) is an important pest causing rice yield reduction. The purpose of this study is to evaluate the sublethal effects of strain BEdy1 Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) on S. furcifera using the two-sex life table analytical method, compare the life tables of the F₀ and F₁ generations of WBPHs which were treated with sublethal concentrations (LC₁₀, LC₂₅) of B. bassiana BEdy1 with a control group. The results showed that the duration of the egg, 4th-instar and 5th-instar nymph, pre-adult, total pre-oviposition (TPOP) and mean generation time (T) for the LC₂₅ treatment were significantly longer than those of the control and LC₁₀ treatment. However, the duration of the adult, the longevity of male and female adults and the oviposition days of female adults for the LC₂₅ treatment were significantly shortened. The fecundity of female adults, intrinsic rate of increase (r), net reproductive rate (R₀) and finite rate of increase (λ) for the LC₂₅ treatment were significantly decreased compared with those of other treatments. The duration of the egg and pre-adult stage for the LC₁₀ treatment were longer than those of the control group, but the population parameters showed no significant difference. Therefore, the LC₂₅ of B. bassiana BEdy1 can inhibit the population growth of S. furcifera. Full article

Assessing the influence of landscape pattern changes on ecosystem service value (ESV) is critical for developing land-use polies and increasing ecosystem services. The data sources include remote-sensing image data and statistical yearbooks from 2000, 2010, and 2020. This study employs the patch-generating land-use simulation model, landscape pattern index, and ecological service value estimation to analyse the changes in landscape patterns and ESV in Fujian coastal areas over the last 20 years. The landscape pattern and ESV in the future (2050) are then simulated under the low-carbon scenario (LCS), with the natural development scenario (NDS) serving as a comparison. The results show that: (1) the most noticeable changes from 2000 to 2020 are the reduced cultivated land area and the rapid expansion of construction land area. By 2050, construction land will account for 7.67% of the total land area under LCS, whereas NDS will account for 9.45%, and changes in the landscape pattern indices all indicate there will be greater variety and fragmentation of the landscape, with the NDS being more serious than the LCS; (2) From 2000–2020, the total ESV value showed a decreasing trend. In 2050, the ESV under the LCS will be 122.387 billion yuan, which is higher than the 121.434 billion yuan under the NDS. Regulating services contribute the most to the total ESV, followed by support services; and (3) In the past 20 years, except for a slight increase in water area, the ESV of other landscapes has decreased, with a net decrease of 3.134 billion yuan in total. The R² fitting between the area change of cultivated and construction land and the total ESV reached 0.9898 and 0.9843, respectively. The correlations between ESV and landscape indices indicate that landscape pattern changes significantly impact ESV. Simulating ESV in LCS can provide guidance for optimising landscape patterns, promoting the benign operation of the regional ecosystem, and achieving sustainable ecological development. Full article

The brown planthopper (BPH) Nilaparvata lugens and white-backed planthopper (WBPH) Sogatella furcifera are serious rice insect pests that cannot overwinter in Korea and migrate from southeast Asian countries and China. In this study, we investigated the sublethal effects of imidacloprid and sulfoxaflor on the biological parameters and feeding behavior of planthoppers. These sublethal concentrations significantly decreased the net reproduction rate (R₀), the intrinsic rate of increase (r_m), and the mean generation time (T). For BPHs, the total durations of nonpenetration (NP) waveform by imidacloprid (LC₁₀ = 164.74 and LC₃₀ = 176.48 min) and sulfoxaflor (LC₁₀ = 235.57 and LC₃₀ = 226.93 min) were significantly different from those in the control group (52.73 min). In addition, on WBPHs, the total durations of NP waveform by imidacloprid (LC₁₀ = 203.69 and LC₃₀ = 169.9 min) and sulfoxaflor (LC₁₀ = 134.02 and LC₃₀ = 252.14 min) were significantly different from those in the control group (45.18 min). Moreover, the LC₁₀ and LC₃₀ of these insecticides significantly decreased the phloem feeding time. In conclusion, imidacloprid had a better effect on the inhibition of feeding of the WBPH, and sulfoxaflor showed a better effect on the inhibition of feeding of the BPH. Therefore, it is suggested that treatment with sublethal concentrations of the above insecticides will reduce the feeding of BPHs and WBPHs on rice phloem. Full article