Quantitative structure-activity studies of benzoylphenylurea larvicides: I. Effect of substituents at aniline moiety against Chilo suppressalis walker

The larvicidal activity of a series of N-2,6-difluoro- and N-2,6-dichlorobenzoyl-N′-(4-substituted phenyl)ureas against nondiapause larvae of the rice stem borer, Chilo suppressalis Walker, was measured by topical application and oral administration methods under conditions with and without piperonyl butoxide as an inhibitor of oxidative metabolism. The effects of substituents at the anilide moiety on the larvicidal activity were analyzed quantitatively using physicochemical substituent parameters and regression analysis. The results indicate that the oxidative metabolism in the larval body which is favored by electron-donating substituents is significant in determining the activity. The activity, when the metabolic factor is eliminated, is enhanced by electron-with-drawing and hydrophobic substituents and lowered by bulky groups. The inhibitory activity against new cuticle formation of the same series of compounds was also measured using cultured integument of the rice stem borer diapause larva. The comparison of the quantitative analyses between larvicidal and integument-level activities shows that inhibition of cuticular development is the most important factor governing larvicidal activity.     

几种杀虫剂防治水稻二化螟田间药效试验

二化螟 Chilo suppressalis( Walker) ,俗称钻心虫 ,是南方稻区水稻上的重要害虫之一。受种植业结构调整和气候变化等因素影响 ,近年来 ,二化螟发生加重 ,在 1 999～ 2 0 0 1年上高县早稻枯心率未防治田一般 2 .7%～ 7.6,高的1 5% ,严重的损失达 50 %以上。为探讨几种不同成份的杀虫剂防治二化螟的效果及有效防治剂量 ,我们于 2 0 0 1年在上高县锦南村早稻田进行了多种杀虫剂防治二化螟的田间药效试验 ,现将结果报道如下 :1　试验条件1 .1　作物品种 :早稻 ,品种为优 I 40 2。1 .2　环境条件 :试验在上高县锦江镇锦南村的双季稻田进行 ,禾…     

Quantitative structure-activity analysis of larvicidal 1-(substituted benzoyl)-2-benzoyl-1-tert-butylhydrazines against Chilo suppressalis

The larvicidal activity of a number of 1-(substituted benzoyl)-2-benzoyl–1 -ten-butylhydrazines against the rice stem borer (Chilo suppressalis Walk.) was measured. Variations in the activity were examined quantitatively using physico-chemical substituent and molecular parameters and regression analysis. The results indicated that the molecular hydrophobicity and the electron-withdrawing inductive/ field effect of ontho substituents are favourable to larvicidal activity. The bulkiness of substituents at the meta and para positions was unfavourable to activity, substitution at the para position being more unfavourable than that at the meta position in terms of van der Waals' volume. The 2,3–, 2,5- and 2,6-disubstitution patterns were also unfavourable to activity. Reductions in larvicidal activity caused by the 2,6-,- 2,3,5- and 2,3,4,5-substitutions were greater than those induced by the 2,3- and 2,5-disubstitutions. When the sum of contributions from favourable effects is greater than that from unfavourable effects, the larvicidal activity is expected to be superior to that of the unsubstituted compound.     

40%氯虫苯甲酰胺·噻虫嗪水分散粒剂防治二化螟田间药效试验

通过田间试验研究不同药剂对二化螟防治效果、产量及用药成本的影响。结果表明,40%氯虫苯甲酰胺·噻虫嗪水分散粒剂10 g/667m2防治晚稻二化螟的效果明显高于常规用药15%阿维·三唑磷乳油100 mL/667m2,且40%氯虫苯甲酰胺·噻虫嗪水分散粒剂10 g/667m2能起到保护生态环境,减少农药用量、降低农药残留的作用。施药方法：于第3代二化螟卵孵盛期至2龄高峰前施药,可提高防效4.98%,每667 m2减少施药工本6元,增加产量31 kg,减少用药成本11元,667 m2增加总效益79.4元。     

Quantitative structure-activity studies of insect growth regulators: XIX. Effects of substituents on the aromatic moiety of dibenzoylhydrazines on larvicidal activity against the beet armyworm Spodoptera exigua

Larvicidal activity against the beet armyworm, Spodoptera exigua (Hübner), was measured after topical treatment for a series of N-tert-butyl-dibenzoylhydrazines having various substituents in the benzoyl (A-ring) moiety closer to the tert-butyl group, the other benzoyl (B-ring) moiety being unsubstituted. The effects of substituents on the larvicidal activity were analyzed using the classical quantitative structure-activity relationship (QSAR) procedure. Introduction of hydrophobic substituents with a small volume into any position was favourable to activity. The existence of electron-withdrawing substituents at ortho positions was also favourable to activity. For multi-substituted compounds, physico-chemically unknown unfavourable factors were suggested to remain after separating common substituent effects derived from QSAR for mono-substituted analogues. With the exception of the unsubstituted compound RH-5849, the effect of substituents in the A-ring moiety on the larvicidal activity was similar to those found with the lepidopteran rice stem borer, Chilo suppressalis (Walker). The larvicidal activity of RH-5849 against S exigua was significantly lower than the value predicted from the correlation between activities against S exigua and C suppressalis. Topical treatment with piperonyl butoxide, a synergist inhibiting oxidative metabolism, slightly enhanced the larvicidal activity of RH-5849 against S exigua.     

Quantitative structure-activity studies of insect growth regulators: XVIII. Effects of substituents on the aromatic moiety of dibenzoylhydrazines on larvicidal activity against the Colorado potato beetle Leptinotarsa decemlineata

Larvicidal activity against the Colorado potato beetle Leptinotarsa decemlineata (Say) was measured for a series of N-tert-butyl-dibenzoylhydrazines having various substituents on the benzoyl (A-ring) moiety nearer to the tert-butyl group, with the other benzoyl (B-ring) moiety being unsubstituted. The effects of these substituent on the larvicidal activity were analyzed using classical quantitative structure-activity relationship (QSAR) procedures. The effects of substituents on the A-ring moiety on larvicidal activity were entirely different from those against the lepidopteran rice stem borer Chilo suppressalis (Walker) previously reported. Position-specific steric and hydrophobic effects, as well as certain substitution patterns, were likely to participate in modifying the larvicidal activity. The activity of para-substituted compounds was generally lower than that of un-, ortho- and meta-substituted compounds. Most multi-substituted compounds showed an activity equivalent to or lower than that of the unsubstituted compound. Among 46 compounds tested, the 2-sec-butoxy analogue was most potent against L decemlineata, although this compound had previously been shown to be only weakly active against C suppressalis.     

丙溴磷、辛硫磷及其混剂对二化螟的毒力测定和田间药效试验

采有点滴法测定丙溴磷、辛硫磷及其混剂对二化螟的毒力,结果表明,丙溴磷与辛硫磷混配,各个配比均有增效作用,其中以6:19(有效成分)的配比增效作用最大,毒性比率和共毒系数分别为1.71和177.16。田间试验表明,丙溴磷与辛硫磷以6:19的混剂对二化螟有较好的防治效果,室内结果在田间试验中得到验证。     

水稻螟虫发生动态与循证控制方案中的若干问题

对近年来长江中下游地区水稻二化螟和三化螟种群回升、危害加重的原因进行了讨论;并就目前螟虫综合治理中在管理与技术上出现的问题,提出了针对螟害治理的循证控制概念和措施。     

二化螟性诱芯不同存贮期对诱蛾效果的影响

二化螟性诱芯的存贮期对田间雄蛾诱捕量有明显影响。试验在长春市进行 ,根据诱芯存贮期长短设置 2个处理 ,分别为 - 18℃条件下存贮 2～ 6个月和同样条件下存贮 33～ 37个月。结果表明 ,从 5月 19日到 9月 2 0日两种贮存期的诱芯平均每盆每日诱蛾量分别为 35 8头和 5 5头 ,后者下降 84 6 %。两种贮存期处理的单盆 1日最大诱蛾量分别为 2 2 3头和 2 0头 ,但不同处理所反映的田间蛾期却基本一致     

二化螟性诱芯不同存贮期对诱蛾效果的影响

二化螟性诱芯的存贮期对田间雄蛾诱捕量有明显影响。试验在长春市进行 ,根据诱芯存贮期长短设置 2个处理 ,分别为-18℃条件下存贮 2～6个月和同样条件下存贮 33～37个月。结果表明 ,从5月 19日到 9月20日两种贮存期的诱芯平均每盆每日诱蛾量分别为35.8头和5.5头 ,后者下降84.6%。两种贮存期处理的单盆1日最大诱蛾量分别为223头和 20头 ,但不同处理所反映的田间蛾期却基本一致     

Computer-simulated evaluation of insect phenology models developed in the tropics: Chilo suppressalis (Walker) as an example

For beneficial insects--predators and parasitoids--to be used effectively within pest control scenarios, it is often necessary to have fundamental as well as more applied information about them, including data on population dynamics, host switching and breeding systems. In recent years, such information has been gained by the use of molecular DNA markers. In this article, we briefly discuss the range of molecular markers available and their potential uses, concentrating on how particular markers have been employed to unravel different patterns of behaviour. Whilst alternative methods of tracking insects have proved highly informative when applied over small geographical scales (e.g., fluorescent dyes and radar transponders as attached to bees, etc), these approaches tend to be confined to studies of movement rather than other potentially important behaviours.     

二化螟性诱剂和诱盆设置技术的研究

通过对二化螟性诱剂水盆诱捕器及其设置高度比较研究,结果表明：诱捕器的口径大小以２４ｃｍ为佳,绿色水盆的诱蛾量比其他颜色的要大;在越冬代诱捕中,诱盆的高度在２０ｃｍ左右效果较好;性诱剂离水面的高度对二化螟雄蛾的诱捕有一定影响,其高度在０.５～１.０ｃｍ的诱蛾量最高。     

Quantitative structure—activity relationships of light-dependent herbicidal 4-pyridone-3-carboxanilides I. Effect of benzene ring substituents at the anilide moiety

A number of substituted 4-pyridone-3-carboxanilide derivatives show various degrees of light-dependent herbicidal activity. The effects of substituents at the anilide moiety on the activity against Echinochloa oryzicola were analysed quantitatively with physicochemical substituent parameters. The activity was shown to vary parabolically with total hydrophobicity (Σπ) of the anilide ring substituents as well as with the steric parameter (E_s) of the ortho-substituents. The E_s parameter for only the bulkier ortho-substituent, with the more negative value, but not for the two, was significant. The effect of substituents at the 1-position was expressible by indicator variables assigned to each 1-substituted series, the physicochemical rationalization being left for future analyses.     

Quantitative structure-activity studies of substituted benzyl chrysanthemates: 1. Correlations between symptomatic and neurophysiological activities against American cockroaches

A number of substituted benzyl (1R)-trans-chrysanthemates and related compounds were synthesized. Their symptomatic activities in terms of levels which induce convulsions as well as cause death in American cockroaches were determined by injection with and without application of synergists as inhibitors of metabolism. The neuroexcitatory and neuroblocking activities were also determined in terms of minimum effective concentrations to induce repetitive train of impulses and conduction blockage, respectively, to central nerve cords excised from the cockroaches and immersed in Ringer's solution. Correlations between symptomatic and neurophysiological activities were analyzed quantitatively with the aid of molecular hydrophobicity parameter and regression analysis. Each symptomatic activity from which the effect of metabolism is eliminated was found to be analyzable by means of a linear combination of indices for two types of neurophysiological activity when the transport factor is separated by using the hydrophobicity parameter. A closer correlation was found between neuroblocking activity and the “convulsive” effect than between neuroexcitatory activity and the “convulsive” effect, whereas both neurophysiological effects operate together on the cockroaches resulting in paralysis and death.     

Efficacy of insecticides against the Rice Stem-borer,Chilo suppressalis (Walker) (Lepidoptera: Crambidae), and use of sex pheromones to time accurately the yearly application

Larvae of the Rice Stem-borer, Chilo suppressalis (Walker), cause extensive crop losses worldwide. Since pesticide application is the major management tactic in China, judicious timing of a minimal dose of insecticides is important in developing an IPM program for that pest. Pheromone trap captures of male moths were used to time the single insecticide application in two seasons (2010 and 2011). In 2010, six pesticides – deltamethrin, cygon, chlorpyrifos, cartap, fipronil, and esfenvalerate – gave >90% control of stem-borers, and reduced damage to less than 5.0%. In 2011, control exceeding 90% and a damage level of <5.0% and was achieved with 0.35 kg/ha deltamethrin and chlorpyrifos. Cygon, at either 0.30 or 0.35 kg/ha, provided control exceeding 90% and a damage level of <4.0%. With the proviso that the impact of insecticides on biological control agents remains to be investigated, these three insecticides are recommended for use by Chinese rice farmers.     

Quantitative structure-activity studies of substituted benzyl chrysanthemates: 2. Physicochemical substituent effects and neurophysiological and symptomatic activities against American cockroaches

The substituent effects on the symptomatic and neurophysiological activities of a number of substituted benzyl (1R)-trans-chrysanthemates against American cockroaches were quantitatively analyzed using electronic, hydrophobic, and steric parameters. The effects were shown to be highly specific to substituent positions except for those on the neuroblocking activity. Steric effect of substituents represented by van der Waals volume was found to play the most significant role in determining the variation in each activity. Peculiar substituent effects depending upon the bulkiness and position of substituents, which had been observed in the toxicity of this class of compounds, can be rationalized by the present analysis indicating that the optimum van der Waals volume of substituents is largest at the ortho and smallest at the para position.     

二化螟性诱芯中不饱和十六醛的比例对诱捕效果的影响

作者于2006年夏季在河南信阳地区系统比较了二化螟性诱芯中Z11-/Z9-16∶Ald及Z13-18∶Ald剂量对2个世代的二化螟雄蛾诱捕量的影响。结果表明,二化螟越冬代成虫诱捕试验中,2个最佳配方中Z11-/Z9-16∶Ald分别为9∶1和8∶2,而比例在7∶3~1∶9之间的诱芯则无引诱作用。如果保持诱芯中Z11-16∶Ald和Z9-16∶Ald的剂量一致且质量比控制在2∶1,则二化螟诱捕量随诱芯中所含Z13-18∶Ald剂量的增加而下降。所有诱芯在二化螟第一代引诱效果显著下降,但该时期组分为Z11-16∶Ald(2)、Z9-16∶Ald(1)、16∶Ald(0.7)和Z13-18∶Ald(0.37)的诱芯诱捕量显著优于其他配比。     

四川省稻田越冬代二化螟寄生性天敌的研究

二化螟Chilo suppressalis是水稻生产上重要的常发性害虫, 以大龄滞育幼虫在稻桩中越冬, 研究其寄生性天敌, 对于害虫发生动态预警和防治具有重要意义。通过剥查四川地区稻桩内越冬代二化螟幼虫并室内饲养羽化收集天敌, 鉴定天敌种类和调查自然寄生率发现:2017年-2018年, 2018年-2019年及2019年-2020年, 寄生蜂自然寄生率分别为1.1%~8.6%, 1.5%~11.7% 和 1.9%~9.0%, 年度间自然寄生率无明显差异; 寄生蜂自然种群主要有螟甲腹茧蜂 Chelonus munakatae (Munakata)、大螟钝唇姬蜂 Eriborus terebrans (Gravenhorst)、中华茧蜂 Amyosoma chinensis (Szepligeti)、绒茧克氏金小蜂Trichomalopsis apanteloctena (Crawford)、螟蛉瘤姬蜂 Itoplectis naranyae (Ashmead)、螟黄足盘绒茧蜂 Cotesia flavipes (Cameron)、环腹瘿蜂 Figites sp.、稻螟小腹茧蜂 Microgaster russata (Haliday)、黏虫白星姬蜂 Vulgichneumon leucaniae (Uchida)和二化螟黑卵蜂Telenomus chilocolus(Wu et Chen)。四川省越冬代二化螟寄生性天敌的优势种为螟黄足盘绒茧蜂和螟蛉瘤姬蜂, 部分地区每年自然寄生率维持在较高的水平。