描述:To develop low-foam pesticide adjuvants, an novel allyl polyoxyethylene methyl ether modified trisiloxane surfactant (2a) was prepared by adding heptamethyltrisiloxane to allyl polyoxyethylene (n = 7) methyl ether (1a). The structure of 2a was confirmed by FT-IR and ¹H NMR. The surface tension of the 2a aqueous solution with a mass fraction of 0.1% was lower than 20.50 mN/m. The 30 s spreading diameter was 52.5 mm. And the foam volume was 36 mL. Overall, its comprehensive performance is comparable to foreign low-foam pesticide additives. Compared with the widely used pesticide adjuvant FGM683, 2a could reduce the amount of foam by more than 50%. The results of indoor biological activity tests showed that after adding 0.1% of 2a to thiamethoxam 250 water-dispersible granules (WG), the LC50 value to N. lugens was 1.55 (1.27-1.82) mg/L, while the LC50 value without 2a was 2.01 (1.71-2.34) mg/L. Field test results showed that when 2a at the dose of 90 g/hm² was added to the thiamethoxam 250 WG at the dosage of 225 g/hm², the control effect on N. lugens was increased by 5.8% 3 days after drug application and increased by 9.0% 7 days after drug application. The results of this study show that low foam polyether modified trisiloxane 2a can significantly increase the control effect of thiamethoxam 250 WG on N. lugens. It can be used as a tank mixing aid for the control of N. lugens in rice fields.
描述:Using antifungal medication econazole as the lead compound, a series of 1-[2-benzyloxy-2- (2,4-difluorophenyl) ethyl]-1H-1,2,4-triazole derivatives were designed, synthesized, and characterized by 1H NMR, 13C NMR and HRMS. The in vitro fungicidal activities of those compounds against 7 plant pathogenic fungi were evaluated to discover effective compounds preliminarily. The efficiencies of the most effective compounds were further tested against rice sheath blight and wheat stripe rust in greenhouse and field. Furthermore, the inhibitory effect on the ergosterol biosynthesis of R. solani also were determined. Most of the target compounds exhibited good fungicidal activities against the tested plant pathogenic fungi in vitro, especially against Rhizoctonia solani and Alternaria solani. By measuring their EC50 values, it was found that the EC50 values of the tested compounds against R. solani were less than 3 μmol/L, which were significantly higher than those of difenoconazole and econazole. The EC50 values of 4a, 4b, 4c, 4g, 4i and 4l against A. solani were all lower than 10 μmol/L. Compounds 4b and 4i showed higher than 70% control efficiencies against wheat stripe rust at 250 μmol/L in greenhouse. And the control efficiency of compound 4b against wheat stripe rust was 81.93% at 240 g a.i./hm2 in field. In addition, compounds 4b and 4i were found to be effective in inhibiting ergosterol biosynthesis of R. solani with the inhibition rate of around 80% at the concentration of 100 μmol/L.
描述:Diflufenican is a carotenoid biosynthesis inhibiting herbicide, the synergistic effect, and field efficacy of diflufenican mixed with acetolactate synthase inhibiting herbicide penoxsulam against weeds in rice were evaluated in greenhouse and field. The results showed that penoxsulam combined with diflufenican exhibited an additive effect for the control of Echinochloa crusgalli, Digitaria sanguinalis, Cyperus difformis and Eclipta prostrata. When the dose ratio of penoxsulam and diflufenican was (1- 2)﹕(5-10), the weed control efficacy was higher than penoxsulam or diflufenican applied alone. The results of field experiments showed that the penoxsulam + diflufenican 300 g/L SC was safe for transplanted rice, and had good efficacy against E. crusgalli, C. difformis, Ammannia arenarid, and Ludwigia prostrata by spraying treatment on stem and leaf of rice 8 days after transplanting, especially to the notorious weeds such as A. arenarid and L. prostrata. The ratios of weed density and the fresh weight reduction were 93.8%-95.8% and 94.1%-96.1% 35 days after treatment with the doses of the active ingredients as 112.5-135.0 g/hm2 . The mixtures had significantly higher control efficacy than the conventional herbicides bensulfuron methyl + acetochlor 22% WP and penoxsulam or diflufenican alone. The combination of penoxsulam and diflufenican was safe for rice and could expand the weed control spectrum with high efficacy, which could be used in transplanted rice fields for annual weed control.
描述:Grapholita molesta (Busck) is an important pest in fruit tree production in northern China. In order to determine the resistance level of G. molesta population to commonly used insecticides in Gansu Province, the sensitivity of field populations of G. molesta from three different areas to eight insecticides was determined by the egg dipping method and the status of insecticide resistance was analyzed. The results showed that field populations of G. molesta showed moderate resistance to spinetoram (RR = 10.24-14.27), low to moderate resistance to deltamethyrin (RR = 8.85-11.44), moderate resistance to lambda-cyhalothrin, chlorantraniliprole and spirotetramat (RR = 18.89-86.62), and high resistance to abamectin, emamectin benzoate and indoxacarb (RR = 99.82-189.81). The results provide a scientific basis for the scientific and rational application of insecticides in the control of G. molesta in orchards.
描述:A new bioassay method of residual film in glass tube was developed for the study of Diaphorina citri (Kuwayama) adult. The sensitivity of 4 field populations of D. citri to 6 insecticides was evaluated. The results indicated that the D. citri was susceptible to thiacloprid, thiamethoxam and chlorpyrifos with the resistance ratios in the range of (0.57-3.07)-fold. However, Lingchuan population in Guangxi Province developed moderate level of resistance to imidacloprid, with the resistance ratio of 18.90-fold. Meanwhile, Lingchuan population developed 9.72-fold resistance to lambda-cyhalothrin. Moreover, Lingchuan and Yongfu populations in Guangxi Province had developed low resistance levels to the novel insecticide sulfoxaflor, and the resistance ratios were over 5-fold. These results were in accordance with the reported documents about the control efficacy in field. It is helpful to set up a standard method to monitor the sensitivity dynamic of D. citri.
描述:Pydiflumetofen is a novel succinate dehydrogenase inhibitor (SDHI), which shows excellent inhibitory activity to many plant pathogens, such as Fusarium graminearum and Sclerotinia sclerotiorum. In this study, the sensitivity to pydiflumetofen of Passalora fulva strains collected from 8 cities in Shandong Province were tested by using mycelial growth rate method. In addition, the control efficacy of pydiflumetofen to tomato leaf mold were also investigated in field. The results showed that pydiflumetofen had strong inhibitory activity on three developmental stages of P. fulva, and the inhibitory activities on spore gemination and germ tube elongation were higher than that on mycelial growth. Inhibition rate of pydiflumetofen to spore gemination and germ tube elongation of P. fulva was over 50% at 0.10 μg/mL. The EC50 values frequency distribution of 103 P. fulva isolates to pydiflumetofen on mycelial growth was a unimodal curve and could be regarded as the baseline sensitivity. The EC50 values ranged from 0.04 to 1.74 μg/mL, with a mean of (0.67 ± 0.41) μg/mL. In field trials of two years, after the last application at the dose of 200 g a.i./hm², the control efficacy of pydiflumetofen was above 80%, which was significantly higher than that of thiophanate-methyl (540 g a.i./hm² ) and fluopyram (150 g a.i./hm² ). This study provides data support for monitoring the resistance of tomato leaf mold to pydiflumetofen and for efficient controlling tomato leaf mold.