【作者】 张海艳；

【导师】 韩召军；

【作者基本信息】 南京农业大学 ， 农业昆虫与害虫防治， 2011， 硕士

【摘要】 大螟(Sesamia inferens (Walker))是水稻的重要害虫之一。其寄主范围广,通常在稻田周边零星发生,对水稻的危害总体不及二化螟和三化螟。近年来随着耕作制度的变化,以及作物布局的多样化,致使大螟发生危害逐年加重,在有些地区甚至成为水稻螟虫的优势种。但水稻螟虫的防治习惯于以防治二化螟和三化螟为主,兼治大螟,很少专门考虑或测定药剂对大螟的有效性。本研究根据水稻螟虫防治需求,首先以饲料涂药法建立了杀虫剂对大螟的毒力测定技术,同时利用江苏南京和浙江温岭两地田间大螟为试虫,测定了常用杀虫剂对大螟的毒力差异,并研究了几种抗性水平较高的药剂的抗性机理,以及药剂增效复配最佳配比的筛选,旨在为生产上防治大螟提供合理用药的理论依据。1.大螟田间种群对不同杀虫剂的敏感性测定连续2年用新建的饲料涂药法测定了十多种常用杀虫剂对江苏南京和浙江温岭地区大螟的毒力状况,通过对比分析发现,除杀虫单和三唑磷等少数药剂外,大螟对多数杀虫剂没有产生明显的抗药性,地区和年度之间敏感性变化不大。不同药剂对大螟的毒力顺序为：甲维盐>>阿维菌素>>稻丰散≈氯虫苯甲酰胺>>氟铃脲≈虫酰肼>茚虫威>醚菊酯>杀螟硫磷≈丙溴磷>三唑磷≈丁烯氟虫腈≈毒死蜱>>杀虫单。与二化螟对比分析发现,大螟对不同药剂的敏感性与二化螟有明显的差异,大螟对稻丰散和丙溴磷的敏感性显著高于二化螟,而对阿维菌素、氯虫苯甲酰胺和毒死蜱的敏感性则显著低于二化螟。讨论认为,近些年大量使用阿维菌素和毒死蜱防治水稻螟虫和飞虱,不利于对大螟的兼治。而针对性的防治大螟,可以利用其敏感性特性,充分发挥稻丰散和丙溴磷等低毒廉价有机磷杀虫剂的作用。2.大螟抗药性的生化机制分别测定了三种增效剂(PBO、DEM、TPP)在大螟温岭种群、南京种群和室内敏感性恢复种群中对不同杀虫剂的增效作用,同时比较测定了这3个种群大螟幼虫的酯酶、谷胱甘肽S-转移酶和多功能氧化酶的活性。结果显示：3种增效剂对杀虫单均没有明显的增效作用。TPP对甲维盐的增效效果最好,其次是DEM, PBO仅在高耐种群中表现出显著增效。PBO和DEM对醚菊酯都具有很好的增效作用,但TPP没有增效作用。TPP对三唑磷的增效效果最好,其次是DEM,但PBO没有增效作用。PBO对丙溴磷的增效效果最好,TPP略有增效,而DEM则没有明显的增效作用。酶活力测定发现,南京种群、温岭种群和室内敏感性恢复种群间多功能氧化酶活性均存在显著性差异,并与其耐药力水平呈正相关。温岭种群的酯酶活性显著高于南京种群和室内饲养品系,后两者没有显著差异。谷胱甘肽S-转移酶以DCNB为底物时,两田间种群不存在显著的活力差异,但显著高于室内饲养品系。讨论认为大螟的耐药性和抗药性大都与解毒代谢酶有关；不同药剂的耐药性增加或抗药性发生所涉及的代谢酶有明显差异；而对同一种药剂来说,随着害虫抗性的增强,参与的代谢酶也有明显的变化。3.稻丰散与甲维盐及氟铃脲复配最佳配比的筛选依据毒力测定资料选择甲维盐、稻丰散和氟铃脲为有效单剂,进行增效复配组合的筛选。结果发现甲维盐与稻丰散不同配比的共毒系数顺序为CTC1:2>CTC1:4 >CTC1:1>CTC2:1>CTC4:1,以LC5o按1：2复配时的CTC值最大(200.79),增效明显；1：4时的CTC值为135.27,有增效作用；其他三种配比CTC值均小于100,没有增效作用。氟铃脲和稻丰散不同配比的共毒系数表现为CTC1:1>CTC1:2> CTC2:1>CTC1:4>CTC4:1,其中LC50配比为1：1时,共毒系数为227.99,有明显增效作用,配比为1：2、1：4和2：1时,共毒系数分别为118.01、94.03和99.55,表现为相加作用。配比为4：1时,共毒系数为68.18,表现为拮抗作用。由此表明本研究筛选出了2个不同的杀虫剂增效复配组合,建议进一步研究开发,为大螟防治提供新型有效药剂品种。4.大螟不同室内饲养方法比较分别用新鲜茭白饲养法、人工饲料饲养法和稻苗饲养法饲养大螟幼虫,分别统计三龄幼虫成活率,化蛹率,蛹重等,以比较几种饲养方法的差异。研究发现：用新鲜茭白饲养法和人工饲料饲养法饲养的大螟,其三龄幼虫成活率没有明显差异,分别为79%和74%,但化蛹率(47%和34%)和平均蛹重(195.04mg和147.21mg)差别较大,新鲜茭白饲养的大螟的化蛹率和蛹重均明显高于人工饲料饲养的大螟。而稻苗饲养法饲养的大螟三龄幼虫成活率很低,不到10%,且无法生长到化蛹。由此认为室内饲养二化螟非常成功的稻苗饲养法不适宜用于大螟饲养,大螟室内繁殖以茭白饲养法为好,人工饲料饲养法还有待进一步改进。本研究筛选建立的大螟室内饲养技术和大螟饲料涂药法杀虫剂毒力生测技术,为大螟研究提供了实用技术,调查大螟的抗药性现状、筛选有效杀虫剂和增效复配组合,为大螟防治提供了用药选择依据和开发新型高效药剂的途径,而测定不同增效剂对不同药剂的增效作用,同时分析增效作用与不同种群的耐药性和解毒酶活力的关系,为探索大螟对不同杀虫剂的抗性机理和抗性早期发生机制提供了进一步研究的思路。更多还原

【Abstract】 Pink stem borer, Sesamia inferens (Walker), is one of the most important insect pests of rice. However, this pest has a broad range of host plants, and usually occurred at out part of paddy field and damaged less serious than Chilo suppressalis (Walker) and Tryporyza incertulas (Walker). In recent years, with the changes in cultivation and diversification of crops, the damage caused by this pest becomes serious year by year. In some areas, pink stem borer even becomes the dominant species of rice borers. But people is still used to controlling rice borers with the insecticides targeting at C. suppressalis and T. incertulas. Little attention has been put on the control methods against S. inferens. In order to select available insecticides against S. inferens and meet the demands for rice pest control in the new situation, this study surveyed on insecticide susceptibility with borers collected from both Nanjing, Jiangsu Province and Wenling, Zhejiang Province in two consecutive years (2009-2010) with a developed bioassay. Resistance mechanisms of S. inferens to several insecticides were also analysized, and the mixtures given best synergism were also selected with Phenthoate and Emamectin benzoate or Hexaflumuron. 1. Susceptibility of S. inferens of field populations to various insecticidesIn this study, S. inferens in Nanjing, Jiangsu Province and Wenling, Zhejiang Province had been collected and tested for their susceptibility to various insecticides in two consecutive years (2009-2010), by using newly developed artificial diet residue bioassay method. Results showed that S. inferens had not developed obvious resistance to most insecticides except for Monosultap, Triazophos and few others which had been used extensively for long time. Little change in sensitivity to various insecticides was found between different geographical population and different years. The toxicity of 14 insecticides to S. inferens was tested and ordered as:Emamectin benzoate>> Abamectin>> Phenthoate≈Chlorantraniliprole>> Hexaflumuron≈Tebufenozide> Indoxacarb> Phenothrin> Fenitrothion≈Profenofos≈Triazophos≈Butene-fipronil≈Chlorpyrifos>> Monosultap. Comparison analysis revealed that S. inferens and C. suppressalis had different sensitivity to various insecticides. S. inferens was found much more sensitive to Phenthoate and Profenofos than C. suppressalis. But to Abamectin, Chlorantraniliprole and Chlorpyrifos, S. inferens was much more tolerant. Finally, it was thought that extensive use of Abamectin and Chlorpyrifos for control of rice borers and planthoppers in recent years was not conducive to the control of S. inferens. For the control targeting at S. inferens, cheap organophosphorus pesticides with low toxic side effect, such as Phenthoate and Profenofos, could play full roles.2. Mechanisms for insecticide resistance in S. inferensThe synergisms of piperony butoxide (PBO), diethylmeleate (DEM) and triphenyl phosphate (TPP) on Monosultap, Emamectin benzoate, Phenothrin, Triazophos and Profenofos in S. inferens of Jiangsu and Zhejiang populations and a strain reared for one year in laboratory were tested together with the activity of three detoxification enzymes in their body. The results showed that all three synergists had little effects on Monosultap. TPP exited some synergistic effects on Emamectin benzoate and Triazophos, PBO showed some synergistic effects on Profenofos; Both PBO and DEM exhibited some synergistic effects on Phenothrin. Enzyme activity tests showed that the activity of MFO changed significantly among the three populations and was positively related with their insecticide tolerance. Esterase activity is similar between Nanjing population and its recovering laboratory strain, but significantly higher in more tolerant Zhejiang population. The CDNB activity of Glutathione S-transferase was significantly higher in the field populations than in the laboratory recovering strain. Thus, it was though that the enhancement of three detoxification enzymes activity in borers might result in the increase in their resistance level. Resistance mechanisms always varied with insecticides and resistance level. 3. Selection of synergistic insecticide mixturesThe mixtures of Emamectin benzoate and Phenthoate with different ratios were tested, and their co-toxicity coefficient (CTC) values were found as fellows:CTC1:2>CTC1:4> CTC1:1>CTC2:1>CTC4:1. Obviously, the mixture with the ratio of 1 to 2 showed highest synergism (CTC 200.79). The mixture with the ratio of 1 to 4 was also synergistic (CTC 135.27). But all the other mixtures tested with different ratio were not synergistic with their CTC less than 100. When Hexaflumuron mixed with Phenthoate, the mixtures with different ratios were found with their CTC values as fellows:CTC1:1>CTC1:2>CTC2:1 >CTC1:4>CTC4:1. Of which, the value of CTC1:1 was 227.99, which means the mixture with ratio 1 to 1 had the highest synergism. The values of CTC1:2, CTCl:4 and CTC2:1 were 118.01、94.03 and 99.55 respectively, which indicated additive effects. The value of CTC4:1 was only 68.18, which implied antagonistic effect. These results indicated that two different combinations of insecticides with high synergism had been selected. Further research might develop new and effective insecticides against S. inferens.4. Comparison of different indoor methods for rearing S. inferensFresh water-oat, artifical diet, and rice seedlings were, respectively, used for rearing larvae of S. inferens by inoculation of newly hatched neonates, and larval survival rate to 3rd instar, pupation rate and pupa body weight were checked and compared. The results showed that the larval survival rate to 3rd instar was high (79%and 74%) when fed on fresh water-oat or artifical diet, and no significant difference was found between these two rearing methods. However, pupation rate and pupa body weight varied significantly with rearing methods. Feeding on water-oat resulted in significantly higher pupation rate (47%) and heavier pupae (195.04 mg) than rearing with artificial diet (34%and 147.21 mg). When reared with rice seedlings, the larval survival rate to 3rd instar was very low (less than 10%), and no larvae could grow to pupation. These results indicated that rice seedling method, the very successful method for rearing C. suppressalis in laboratory was not appropriate for S. inferens. Fresh water-oat feeding method is the best one while artificial diet feeding method should be further improved.The suitable method for rearing S. inferens indoor and insecticide toxicity bioassay with chemical residues on artificial diet have been selected and established in this study, which provides new practical techniques for the study of S. inferens. Survey on insecticide resistance, and selection of efficient insecticides and their combinations with high synergism provide the basis for reasonable use of insecticides and development of new efficient insecticide formulations for control of S. inferens. The paralellel analysis of the synergism of different synergist on different insecticides, resistance and detoxification enzyme activity in different populations provide ideas for further research pursuing mechanisms and the onset mode for the resistance of S. inferens to different insecticides.更多还原