植物源农药在烟草病虫害防治上的研究与应用

简要介绍了植物源农药的特点、作用方式和开发与应用概况。对植物源杀虫剂、杀菌剂、杀线虫剂和抗病毒剂在烟草病虫害防治上的研究与应用进行了综述,并探讨了植物源农药开发与利用中存在的问题及发展前景。      

Occurrence of fungicide and insecticide residues in trade samples of leafy vegetables

The aim of this work was to report on a total of 23 fungicides and insecticides residues in 75 green and leafy vegetables (Swiss chards, Spinaches and Lettuces) collected from Ourense (NW Spain) by Spring 2007. The pesticides in the study samples were extracted with acetonitrile; the extracts were then cleaned-up by solid-phase extraction and concentrated before determination by PTV (Programmable Temperature Vaporization Injector) – GC-ITMS. Use of analyte protectants mixtures provided the best results in terms of effective compensation for matrix-induced enhancement effect. Pesticide residues were determined above the maxima residue limits (MRL) in 15 of the 75 analyzed samples, with a total of 18 violations of the MRL (three of the samples did not fulfil with two different pesticide MRL). The highest concentrations of fungicides were found in lettuce (procymidone, 12 mg/kg) and the highest concentrations of insecticides were found in Swiss chard (cypermethrin, 6 mg/kg). More positives for fungicides were detected and at larger concentrations than insecticides, especially for lettuces. Accumulation of pesticides in lettuces is higher than for the other leafy vegetables. The findings of this study pointed to the following recommendation: the need for a monitoring program for residues of iprodione and procymidone, together with cypermethrin, in food crops at the national level.     

Residual efficacy of deltamethrin and β-cyfluthrin against Trogoderma variabile and Trogoderma inclusum (Coleoptera: Dermestidae)

Trogroderma variabile Ballion, warehouse beetle, and Trogoderma inclusum LeConte, larger cabinet beetle, are dermestid pests of stored products. A series of laboratory bioassays were conducted to evaluate residual toxicity of the pyrethroids deltamethrin and β-cyfluthrin, applied on a concrete surface substrate for control of adults and larvae of both species, to provide initial baseline susceptibility data for dermestids. Commercial formulations were applied at calculated deposition rates of 8, 16, and 24 mg active ingredient [AI] per m² for deltamethrin and 10 and 20 mg active ingredient [AI] per m² for β-cyfluthrin. Ten adults or larvae of either species were introduced to individual untreated and treated arenas at 0, 0.5, 1, 2, and 3 mo post-treatment. Adult mortality was evaluated after 4 d of exposure with no food provided, and larval mortality was assessed 30 d after exposure with provision of food. Adult mortality of both species exposed to both insecticides ranged from 72.4 ± 6.9 to 100% depending on exposure interval. Larval mortality ranged from 18.3 ± 5.4 to 96.7 ± 2.1% on arenas treated with deltamethrin, and was significantly lower than adult mortality (P < 0.001) at bioassays conducted at 2 and 3 mo post-treatment for both species at all three rates. Larval mortality on arenas treated with β-cyfluthrin ranged from 20.0 ± 4.5 to 71.7 ± 4.8%, and was always lower (P < 0.001) at all exposure times at both rates for both species. There were only 4 out of a possible 20 comparisons with a significant difference (P < 0.05) between the three rates of deltamethrin and no occasions where there is a significant difference in mortality between the two rates of β-cyfluthrin. There were three occasions where mortality of T. inclusum adults or larvae was greater than T. variabile, and one occasion with the reverse, for exposures with deltamethrin. Results show larvae of both species were more tolerant than adults of both species, and larvae could be used as an indicator stage for future studies insecticidal susceptibility of Dermestids.     

3%丰保磷颗粒剂防治甘蔗主要害虫研究

本文报道了混配剂丰保磷（SIP－9001）对甘蔗黑色蔗龟的室内毒力测定和在大田对甘蔗主要害虫的药效试验结果。室内毒力测定，混配剂丰保磷的共毒系数（CTC）为297．5。将混配剂制成3%颗粒剂进行大田药效试验，对黑色蔗龟成虫引起的枯心苗、二点褐鳃金龟幼虫引起的死苗、齿缘鳃金龟幼虫、甘蔗螟虫枯心以及蓟马的防治效果平均分别达到83．6、98.6、80.6、59．6和92．7%。在大田表证示范中，水田蔗区和旱地蔗区分别用3%丰保磷颗粒剂5和6kg／亩，结果：示范区甘蔗枯心苗平均比同剂量对照药呋喃丹分别减少51．0和6．9%；示范区甘蔗产量比同剂量呋喃丹相对增产10．1-42．3%。     

Aerosol insecticide distribution inside a flour mill: Assessment using droplet measurements and bioassays

The distribution of aerosol applications of pyrethrin + methoprene, generated from a mechanical fogger, and pyrethrin + pyriproxyfen, dispensed from a pressurized cylinder, were characterized inside a pilot-scale flour mill using measurements of particle size and concentration and effects on adult confused flour beetles, Tribolium confusum Jacqueline duVal, in bioassay arenas. Particle measurements were made using TSI Aerodynamic Particle Sizer (APS) units placed in an open straight line at distances of 4.3, 8.9, and 13.5 m from the aerosol release point (open configuration). Measurements were also made using a second configuration (termed obstructed), which was done by moving the APS unit at 8.9 m underneath a piece of equipment, and moving the APS unit at 13.5 m behind a support beam. Actual concentration and calculated deposition were about 4× greater for the pyrethrin + methoprene aerosol compared to the pyrethrin + pyriproxyfen aerosol. However, efficacy was similar since bioassays using adult T. confusum showed no difference in recovery after exposure to either insecticide. Concentration and calculated deposition of both aerosols decreased with increasing distance from the spray release point and when the APS units were in the obstructed configuration, and recovery of bioassay insects after exposure increased with increasing distance from the spray release point. Results from this field trial show how efficacy of aerosol applications is impacted by distance and obstacles, and how use of equipment that measures droplet size and concentration can help quantify the dispersion and spread of insecticidal aerosols. Results also provide guidance to develop relationships between aerosol deposition and efficacy and thus improve pest management programs for structural management of stored product insects.     

Degradation and residual efficacy of beta-cyfluthrin as a surface treatment for control of Tribolium castaneum Herbst: Effects of temperature and environment

Concrete arenas were treated with the low and high label rates of beta-cyfluthrin Tempo SC Ultra® (10 and 20 mg Active Ingredient [AI]/m², respectively) and stored during the summer and autumn in two separate years inside an empty grain bin, inside a rice mill, and inside a laboratory at an approximate ambient temperature of 27 °C. Bioassays were conducted by removing the arenas at 0 (1 day) to 10 weeks post-treatment from the three locations where they were stored, and exposing adults of Tribolium castaneum (Herbst), the red flour beetle, for 0.5–3 h on the arenas. Rapidity of knockdown was used to assess residual efficacy. Application rate was significant (P < 0.05) for rapidity of knockdown for the summer storage period but not for autumn (P ≥ 0.05). As the weeks progressed during summer, knockdown was progressively slower during the 0.5 to 3-h exposure period on arenas held inside the grain bin compared to the arenas inside the rice mill and the laboratory. During autumn the order was reversed for the grain bin and laboratory as the weeks progressed but at 10 weeks knockdown after 3 h was still much less on arenas held inside the bin and mill compared to the laboratory. Extreme high temperatures in the grain bin during the summer, and the fluctuating temperatures during autumn, may have promoted residual degradation on arenas held in the bin and mill compared to the constant temperatures in the laboratory. Results show that residual persistence of contact insecticides for control of stored product insects may be less on treated surfaces outside of a laboratory setting, and caution is warranted when predicting time periods for residual efficacy in sites that are outside of research laboratories with stable environmental conditions.     

Degradation and by-product formation of diazinon in water during UV and UV/H(2)O(2) treatment

Kinetics and degradation products resulting from the application of UV and UV/H(2)O(2) to the US EPA Contaminant Candidate List pesticide diazinon were studied. Batch experiments were conducted with both monochromatic (low pressure [LP] UV 253.7 nm) and polychromatic (medium pressure [MP] UV 200-300 nm) UV sources alone or in the presence of up to 50 mg l(-1) H(2)O(2), in a quasi-collimated beam apparatus. Degradation of diazinon by both UV and UV/H(2)O(2) exhibited pseudo first order reaction kinetics, and quantum yield of 8.6 x 10(-2) and 5.8 x 10(-2) mol E(-1) for LP and MP lamps respectively. Photolysis studies under MP UV lamp showed 2-isopropyl-6-methyl-pyrimidin-4-ol (IMP) to be the main degradation product of diazinon at aqueous solution pH values of 4, 7 and 10. Trace levels up to 1.8 x 10(-3) microM of diazinon oxygen analogue diethyl 2-isopropyl-6-methylpyrimidin-4-yl phosphate (diazoxon) were detected only during the UV/H(2)O(2) reaction. Decay of both products was observed, as the UV/H(2)O(2) reaction prolonged, yet no mineralization was achieved over the UV fluence levels examined. Photolysis kinetics, quantum yield and UV/H(2)O(2) degradation of the reaction product IMP was determined using MP UV lamp at pH values of 4, 7 and 10.     

六六六、滴滴涕分析质量控制结果分析

为了解我国检验机构在农药残留检验方面的质量水平，2002年5月使用六六六、滴滴涕质控双样开展了分析质量控制工作。检测结果表明虽然此项检验工作在全国已开展将近30年，但仍存在问题。数据不合格率为16．5％，13家单位中全部结果合格的有7家，3家单位存在较大问题。质量控制工作对于发现问题，促进问题的解决具有重要作用，应当在检测机构经常性开展以保证检测结果的准确。     

Incorporation of in situ and biomarker assays in higher-tier assessment of the aquatic toxicity of insecticides

This study was designed to test the feasibility of integrating in situ, single species exposures and biomarker analysis into microcosm studies. Experimental ponds were dosed with pirimiphos methyl (PM) and lindane. C. riparius fourth instar larvae were deployed for 48h on nine separate occasions during the study period before and after treatment. Surviving larvae were analysed for acetylcholinesterase activity (AChE). Survival and biomarker data were compared to chironomid assemblage analysis by monitoring insects emerging from the microcosms. Survival of chironomids within the in situ systems commenced on day +16 after treatment with 31.6% and 53.3% survival in the lindane and PM treated ponds, respectively. In contrast, the first emergence from the microcosms occurred on days +27, in respect to lindane, and +59 for the PM treated ponds. Thus the in situ bioassay was able to demonstrate gradual reduction in toxicity within the sediment before this was evident from macroinvertebrate monitoring. Significant AChE inhibition was only detected on exposure to PM. Levels decreased from 75% on day +16 to 26% by day +29. The biomarker analysis confirmed that, by the end of the study, the insecticide was no longer exerting an effect. We discuss how the use of in situ bioassays could also aid comparison of microcosm studies by adding a standardized dimension.     

不同杀虫剂对烟田节肢动物群落的影响

本文研究了大田条件下施用吡虫啉、氧乐果对烟田节肢动物群落的影响,施药后害虫和天敌的种群消长动态,并以多样性、相似性指数等生态学参数来衡量2种杀虫剂产生的生态效应及对烟田节肢动物群落时空分布的影响.结果表明,施用氧乐果田块的节肢动物各类群数量都明显下降,天敌恢复较为缓慢,而害虫类恢复则较快,群体数量的急剧变化使得群落稳定性降低;施用吡虫啉的田块,蚜虫、叶蝉等刺吸式口器害虫数量明显下降且不易恢复,天敌类则相对下降不大.初步认为,使用选择性杀虫剂吡虫啉对烟田生物群落物种数量的恢复与保持群落的自我调节能力与自然控制力有重要作用.