Emamectin benzoate 9.7%SL as a new formulation for a trunkinjections against pine wood nematode,Bursaphelenchus xylophilus

In this study,we investigated the preventive effects of emamectin benzoate 9.7%SL,which was newly developed to reduce the injection volume and number of injection holes required to protect against pine wood nematode.None of the Pinus thunbergii trees injected with emamectin benzoate 9.7%SL at 0.3 mL/cm diameter at breast height(DBH)died within 2 years of inoculation with pine wood nematodes.Emamectin benzoate 9.7%SL injected at 0.6 mL/cm DBH resulted in no tree mortality for 3 years.Mean residue of emamectin benzoate 9.7%SL in pine twigs injected with 0.3 mL/cm DBH was 0.490μg/g at 1 year after injection and 0.303μg/g after 2 years.These residues values are greater than 0.031μg/g,previously determined IC95 value for emamectin benzoate against the pine wood nematode.Our field experiment and residue analysis showed that emamectin benzoate 9.7%SL could be a substitute agent for emamectin benzoate 2.15%EC,which is widely used to prevent pine wood nematode in the field and that injection volume and number of injection holes can be greatly educed using this new formulation,which will reduce injury to the cambium,interruption of water movement,and infection of inoculation wounds by wood-decay or blue stain fungi.

Release performance and sustained-release efficacy of emamectin benzoate-loaded polylactic acid microspheres

High-performance liquid chromatography （HPLC） was employed to determine drug release rates based on emamectin benzoate concentrations in the medium. Release kinetics equations were used to fit the drug release behavior. The effects of particle size and release medium pH on the release rate were also investigated. The indoor toxicity of emamectin benzoate-loaded polylactic acid microspheres on the diamondback moth larva （Plutella xylostella） was studied to explore drug sustained-release performance. In acidic and neutral media, the drug release behavior of the microspheres was in accord with the first-order kinetics equation. Increasing the spray dosage of emamectin benzoate-loaded polylactic acid microspheres initially resulted in an equivalent insecticidal efficacy with the conventional emamectin benzoate microemulsion. However, the drug persistence period was four-fold longer than that observed using the conventional formulation. The developed emamectin benzoate-loaded polylactic acid microspheres showed dramatic sustained-release performance. A treatment threshold of greater than 35 mg mL-1 was established for an efficient accumulated release concentration of emamectin benzoate-loaded microspheres.

Synergistic Activity of Organosilicone to Emamectin Benzoate against Beet Armyworm (Spodoptera exigua Hübner)

Based on determination for surface tension of organosilicone solution and its expansion on the solid surface, the biological activity of 5% emameetin ben- zoate WDG with organosilicone against beet armyworm was determined by spraying method to study their synergistic activity. The results showed that organosilicone significandy reduced surface tension of aqueous solution, and the surface tension was reduced to 26raN/m as the concentration of organosilicone was 0.01%. The organosilicone significantly raised expansion of liquid drops on solid surface, and the expansion diameter of 10 μL 0.01% organosilicone was 34 ram. The indoor toxicity results indicated that when addition dosage of organosilieone was 1% -5%, synergistic activity of 5% emamectin benzoate WDG with organosilicone against beet armyworm was significant, and increase extent of synergistic activity slowed down as organosilieone dosage was higher than 5%. Field experiment showed that the control efficacies of 5% emamectin benzoate WDG ＋5% organosilicone 33 mg/ L against beet armyworm were 81.57% and 82.66% after spraying for 3 and 7 d respectively, which were significandy better than treatments of 5% emamectin benzoate WDG 33 rag/L, 24% metaflumizone SC 96 mg/L, 5% chlorantranilip- role SC 33 mg/L, 20% tlubendiamide WDG 40 mg/L and 15% indoxacarb EC 43 mg/L.

Indoor Toxicity of Emamectin Benzoate and Chlorantraniliprole Against Spodoptera litura and Their Residues on Lotus Plants

Spodoptera litura is the most threatening pest in lotus production,seriously affecting the lotus yield and quality.Emamectin benzoate and chlorantraniliprole,the main insecticides for controlling S.litura on vegetables,are widely used by farmers to control S.litura on lotus plants.To determine the application concentrations,control effects,and safety of the two insecticides in lotus fields,indoor experiments were conducted to determine the control effects of 200 g/L chlorantraniliprole(SC)and 5%emamectin benzoate(WDG),and the residues of the two insecticides in the water,lotus leaves,and lotus seeds after field application were determined by HPLC-MS/MS.The indoor experiment results showed that chlorantraniliprole and emamectin benzoate both had good control effects on S.litura,with the median lethal concentrations(LC50)of 17.700 and 1.694 mg/L,respectively.After unmanned aerial vehicle spraying of emamectin benzoate at 20 g/667m^(2),there was no residue of emamectin benzoate in the water or lotus leaves after 5 d.After spraying of chlorantraniliprole at 20 mL/667m^(2),the residual amounts in the water and lotus leaves after 9 d were 0.005 and 0.007 mg/L,respectively.No residue of the two insecticides was detected in lotus seeds(dry and fresh)2 h after spraying.Therefore,it was recommended that chlorantraniliprole and emamectin benzoate can be used to control S.litura in lotus fields during the growth period,while attention should be paid to the application interval for safety.Considering the safe harvesting of lotus seeds and leaves,it was recommended that the preharvest intervals of chlorantraniliprole and 5%emamectin benzoate should be 9 d.

Genotoxicity of Three Avermectins on Polypedates megacephalus Tadpoles Using the Comet Assay

Avermectins are a new class of macrocyclic lactones derived from mycelia of the soil actinomycete, and are used as effective agricultural pesticides and antiparasitic agents. However, run-off from crops treated with avermectins may contaminate various bodies of water, and accumulated to certain concentrations to impact the development of aquatic animals. Here, we tested the genotoxicity of three avermectins （abamectin, ABM; ivermectin, IVM; and emamectin benzoate, EMB） on Polypedates megacephalus tadpoles by the alkaline single-cell gel electrophoresis assay. Tadpoles were treated for 48 h in the laboratory with different concentrations of these three agents, 0.006, 0.012, 0.018, 0.024, 0.030 mg/L for ABM, 0.003, 0.006, 0.009, 0.012, 0.015 mg/L for IVM and 0.04, 0.06, 0.08, 0.10, 0.12 mg/L for EMB, and then measured their DNA damage by the Comet assay tail factor %. The concentrations of resulted in highly significant increases in DNA damage of the tadpoles were found above the concentration threshold of 0.012 mg/ L ABM, 0.003 mg/L IVM and 0.06 mg/L EMB and linear correlations between the intensity of DNA damage and the concentrations of these three avermectins. Our results showed clearly that avermectins caused dose dependent DNA damage on amphibian tadpoles, and there might be a control on the misuse of avermectins.

Challenges and risks associated with impurity profiles in technical grade crop protection products produced semi-synthetically from natural products

The safety of crop protection products and their safe use is of paramount importance and requires that crop protection products are consistently marketed and used worldwide in the required registered quality.To meet these high-quality requirements,the highest demands must be placed on the production and purification of technical-grade crop protection products.In this context,impurity profiles are of utmost importance,as unknown impurities at higher than registered concentrations may pose new unknown toxicological risks to users,consumers,and the environment.Particularly high demands are placed on the production and purification of technical grade semisynthetic derivatives of fermentatively derived natural products to meet the required regulatory specifications,to ensure that relevant impurities do not exceed maximum allowable concentrations,to ensure the safe use of such products,and to eliminate any unknown product safety risks.The challenges associated with the manufacture and purification of Afidopyropen and the product safety risks associated with various qualities of technical grade Emamectin benzoate are discussed in detail.