Pest Management Science最新文献

Background: Accumulation of two or more Bacillus thuringiensis (Bt) proteins in plant not only improves the resistance to pests and broadens the resistance spectrum of crops, but also delays the development of pest resistance.

Results: The self-cleavage peptide sequence was used to link two codon-optimized genes, so as to achieve simultaneous accumulation of two low homologous insecticidal proteins in one plant. The rice transformants accumulating Cry1Ca and Cry2Aa proteins were fed to local lepidopteran pests and the larva mortality in 5 days were 100%. The sum of Cry1Ca and Cry2Aa proteins in leaves of transformants E1C&2A-1 and E2A&1C-18 were 10.60 and 9.55 μg g^-1 fresh weight (FW), respectively, and the larva mortality of fall armyworm fed on their leaves for 5 days reached 100%. For the control transformants that expressed one Bt protein, the content of Cry1Ca in leaves of transformant E1CM031 was 14.94 μg g^-1 FW, and that of Cry2Aa in leaves of transformant B2A4008S was 11.90 μg g^-1 FW, but the larva mortality of fall armyworm fed on leaves of E1CM031 and B2A4008S for 5 days were 77.78% and 52.78%, respectively. Although the total Bt contents in transformants expressing one Bt protein were higher than that of transformants expressing two Bt proteins, the lethality of transformants expressing one Bt protein were obviously lower than that of transformants expressing two Bt proteins.

Conclusion: The lethal effect of accumulating both Cry1Ca and Cry2Aa proteins in rice was stronger than that of amassing Cry1Ca or Cry2Aa protein only, which meant there was synergistic effect between Cry1Ca and Cry2Aa proteins. © 2024 Society of Chemical Industry.

Background: Succinate dehydrogenase (SDH) represents a critical target in the development of novel fungicides. To address the growing issue of resistance and safeguard the economic viability of agricultural production, the pursuit of new succinate dehydrogenase inhibitors (SDHIs) has emerged as a significant focus of contemporary research.

Results: In this project, 32 arylhydrazine derivatives containing diphenyl ether structural units were synthesized and evaluated for their fungicidal activities against Rhizoctonia solani, Sclerotinia sclerotiorum, Alternaria alternata, Gibberella zeae, Alternaria solani and Colletotrichum gloeosporioides. In an in vitro fungicidal activity assay, compound D6 showed significant inhibitory activity against R. solani with a half-maximum effective concentration (EC₅₀) of 0.09 mg L^-1. The in vivo fungicidal activity demonstrated that compound D6 inhibited R. solani by 95.39% in rice leaves, which was significantly better than that of boscalid (85.76%). The results of SDH enzyme assay, molecular docking simulation, mitochondrial membrane potential assay, cytoplasmic release studies and morphological observations demonstrated that the target compound D6 not only had significant SDH inhibitory activity, but also affected the membrane integrity of mycelium.

Conclusion: Bioactivity screening and validation of the mechanism of action indicated that compound D6 was a potentially unique SDHI, acting on SDH while also affecting cell membrane permeability, which deserved further study. © 2024 Society of Chemical Industry.

Background: Fusarium head blight (FHB), mainly caused by Fusarium graminearum (F. graminearum), remains a devastating disease worldwide. The histone acetyltransferase Gcn5 plays a crucial role in epigenetic regulation. Aberrant Gcn5 acetylation activity can result in serious impacts such as impaired growth and development in organisms. The secondary metabolite phenazine-1-carboxamide (PCN) inhibits F. graminearum by blocking the acetylation process of Gcn5 (FgGcn5), and is currently used to control FHB. However, the molecular basis of acetylation inhibition by PCN remains to be further explored.

Results: Our molecular dynamics simulations revealed that PCN binds to the cleft in FgGcn5 where histone H3 is bound, with key amino acid residues including Leu96 (L96), Arg121 (R121), Phe133 (F133), Tyr169 (Y169), and Tyr201 (Y201), preventing FgGcn5 from binding to histone H3 and affecting histone H3 from being acetylated. Experimental validation of key amino acid mutations further confirmed the impact of these mutations on the interaction of FgGcn5 with PCN and histone H3 peptide.

Conclusion: In summary, our study sheds light on the mechanism by which PCN inhibits the acetylation function of FgGcn5, providing a foundation for the development of drugs or fungicides targeting histone acetyltransferases. © 2024 Society of Chemical Industry.

Background: Traditional chemical pesticides are easily lost by surface runoff and only small quantities reach the target, thus causing serious environmental pollution. In this work, dinotefuran@zeolitic imidazolate framework-8@polydopamine@zein (DNF@ZIF-8@PDA@zein), was constructed to deliver DNF with pH and enzyme double response of release, thereby achieving targeted release and efficient long-term pest control.

Results: DNF@ZIF-8@PDA@zein was synthesized with three hydrated diameters (249.73 ± 9.99 nm, 142.94 ± 5.63 nm and 75.16 ± 4.66 nm, respectively). The release of DNF from DNF@ZIF-8@PDA@zein after 28 h was significantly higher at pH 5.0 (89.22 ± 7.18%) compared to that at pH 8 (81.8 ± 6.11%). Protease-assisted release of DNF was notably higher than that without protease (pH 5: 89.22 ± 5.55% versus 27.19 ± 3.22%; pH 8: 81.8 ± 6.11% versus 25.39 ± 3.87%). The stimuli-responsive release of DNF from DNF@ZIF-8@PDA@zein increased with decreased particle size due to increased pore size, reduced binding forces (i.e., weaker π-π stacking, hydrogen bonding, and Zn-N covalent bonding), and the shortening of diffusion path, leading to faster disintegration and drug release. Additionally, the anti-photolysis ability of DNF@ZIF-8@PDA@zein was 3.2 times that of pure DNF. The insecticidal activity improved with smaller nanoparticles due to higher drug release rate and greater inhibition of detoxification enzyme activity by more zinc ion (Zn²⁺) dissolution.

Conclusion: The pH and enzyme dual-responsive release as well as insecticidal activity of DNF@ZIF-8@PDA@zein increase with decreased nanoparticle size, showing effective pest management in long-term and potential application prospects in sustainable agriculture. © 2024 Society of Chemical Industry.

Background: Fungicide residues were frequently detected in vegetables and soils, which severely affected crop yields and qualities. Reasonable nitrogen management might promote yields and decrease fungicide carbendazim residues in plant-soil systems. Current study explores comprehensive relationships among carbendazim residues, crop yields, soil multifunctionalities and endophytic and soil bacterial communities after applying nitrification inhibitors (3,4-dimethylpyrazole phosphate and dicyandiamide) and percarbamide to different soils.

Results: Combined nitrification inhibitor and percarbamide additions produced multi-effects on restoring yields, declining fungicide residues, promoting soil multifunctionalities and stimulating bacterial communities. Relative to the control, percarbamide application promoted carbendazim dissipations in upland soils but decreased bacterial community diversities and stabilities in different soils. Compared to exclusive percarbamide, extra dicyandiamide applications decreased carbendazim residues by 25.8% in upland soils and 70.2% in paddy soils, declined carbendazim residues in carrots via improving soil pH, ammonium nitrogen (NH₄ ⁺-N) and Proteobacteria ratios. Relative to percarbamide application alone, extra dicyandiamide addition promoted the dry carrot yields by 133.2% in upland soils and 33.5% in paddy soils via promoting soil NH₄ ⁺-N, Acidobacteriota and Actinobacteriota ratios and bacterial community diversities and stabilities. Upland soil multifunctionality improvements diminished soil carbendazim residues via promoting soil pH and NH₄ ⁺-N, and paddy soil multifunctionalities and endophytic bacterial community structures generated negative influences on carrot carbendazim residues.

Conclusion: Our study suggested that nitrification inhibitor on the basis of percarbamide generated multi-effects on the different crop-soil systems: restoring carrot yields, reducing carbendazim contents, promoting soil multifunctionalities and stimulating bacterial community diversities and stabilities. © 2024 Society of Chemical Industry.

Background: This study investigates the spatial distribution and aggregation patterns of major insect pests in Kharif rice fields during the 2023 growing season in Eastern India. The analysis focuses on key pests such as yellow stem borer (YSB), gall midge, green leaf hopper (GLH), and brown planthopper (BPH), as well as rice thrips, caseworm, whorl maggot, Gundhi bug, grasshopper, and leaf folder. Using statistical indices, this study aims to understand pest behavior across Standard Meteorological Weeks (SMWs) to better inform pest control strategies.

Results: The study reveals significant clustering and aggregation patterns among the pests. YSB exhibited variance-mean ratio (VMR) values between 1.14 (40th SMW) and 1.96 (31st SMW), with dispersion parameter (K) values ranging from 0.57 to 21.65, and a peak index of dispersion of 132.66 (43rd SMW). Similarly, gall midge showed VMR values from 6.19 to 10.48, whereas GLH and BPH recorded VMR ranges of 1.19 to 132.10 and 1.01 to 1.50, respectively. These spatial distribution trends were confirmed through values for Iwao's patchiness index and Taylor's power law, indicating strong pest aggregation in specific areas.

Conclusion: The results underscore the need for region-specific integrated pest management strategies that take into account pest clustering and environmental factors influencing pest distribution. Although an S-curve pattern of infestation-showing gradual population increases, rapid peaks, and eventual decline-was observed, the primary focus remains spatial patterns, which are critical for optimizing pest management and improving rice crop sustainability in the region. © 2024 Society of Chemical Industry.

Background: Temperature is an important determinant of developmental and reproductive rates in insects. Here, we investigated the physiological responses of adult beet webworm, Loxostege sticticalis L. (Lepidoptera: Crambidae), to three temperatures (16, 23 and 30 °C) focusing on trehalose metabolism.

Results: Exposure of moths to 30 °C accelerated eclosion and ovarian development, but shortened the oviposition period and adult longevity, whereas exposure to 16 °C had opposite effects. Transcriptome analysis revealed that vitellogenin (VG) and vitellogenin receptor (VR) genes were up-regulated at 30 °C, as were numerous genes related to energy metabolism, including those involved in the insulin signaling pathway, the tricarboxylic acid (TCA) cycle, and glycolysis. Expression of the trehalose transporter gene TRET1 was also induced at high temperature, primarily in the ovaries, where trehalose content increased, accompanied by lipid degradation in the fat body. Treatment with the trehalase inhibitor validamycin A reduced female fecundity and longevity at 23 °C, but enhanced the expression of genes related to stress resistance and reproduction, mimicking the effect of high temperature.

Conclusion: Besides their practical utility for predicting the oviposition behavior and geographic distribution of L. sticticalis in the field, these results elucidate the various physiological roles of trehalose in L. sticticalis during exposure of moths to high temperature and may provide insights into the relationship between stress resistance and reproduction in insects more generally. © 2024 Society of Chemical Industry.