竹提取物对玉米象Sitophilus zeamais Motsch.生物活性的初步研究

研究了 10种竹子提取物对玉米象种群形成的抑制作用和驱避作用。结果表明 ,灰水竹和短穗竹提取物对玉米象成虫的驱避效果较好 ,72 h驱避等级达到 级 ,平均驱避率分别为 77.4 4%和6 4.84 %。应用索氏抽提法所得到的灰水竹提取物对玉米象成虫的驱避作用明显强于间歇振荡法所得到的提取物 ,驱避中浓度分别为 0 .9994 g/L。 10 g/L的竹提取物对玉米象种群形成的抑制作用不明显 ,只有白纹短穗竹提取物对玉米象种群的抑制率达到 5 0

Comparative Morphometry of the <i>Sitophilus zeamais</i>Motschulsky Populations (Coleoptera: Curculionidae) Infesting Yellow Maize in Four West African Countries

Sitophilus zeamais is a primary pest of stored maize, which can cause quality and quantity losses. Maize is cultivated in several West African countries where different agro-climatic and agro-ecological conditions exist. These conditions could influence the Sitophilus zeamais morphology. Thus, the purpose of this study is to identify the Sitophilus zeamais morphological groups in the four countries. This was carried out through the morphometric study of 30 male Sitophilus zeamais individuals taken from the yellow maize in each country, by measuring with a binocular magnifying glass, 16 variables of the different tagmas belonging to the insect. Subsequently, statistical analyses were firstly carried out with the raw measurements, such as the principal component analysis, in order to extract the contribution of the variables on each factorial axis and to visualise the correlations between the variables. Taking the case of the transformed measurements, in addition to the principal component analysis, a discriminant factorial analysis was carried out to find out the best factor for gathering individuals according to their morphology, a confusion matrix to summarise the individual’s reclassification in order to deduce the good and bad classification rates, and an ascending hierarchical classification which consists of gathering the individuals according to their similarity and separating them according to their dissimilarity using the truncation method. Therefore, five morphological groups were identified. However, the existence of these morphological groups would not be linked to agro-ecological, climatic conditions and to the geographical remoteness between countries.

Bioactivities of Extracts from Toona sinensis against Sitophilus zeamais

[ Objective ] The repellent activities and contact toxicity of extracts from Toona sinensis against Sitophilus zeamais were studied. [ Meth- od] 95% alcohol, petroleum ether and dichloromethane were selected to extract the active components from the leaves and barks of T. sinensis, respectively. And then the extracts were prepared at 0.6, 0.3, 0.15 g/ml to study the biological activity against S. zeamais in lab. [ Result J The petroleum ether extracts from the leaves of T. sinensis had significantly repellent effects on S. zeamais, but the extracts from T. sinensis with three solvents had no obvious contact toxicity against S. zeamais. [ Conclusion ] The petroleum ether extracts from S. zeamais had certain repellent activity.

Evaluation of the dust and methanol extracts of Garcinia kolae for the control of Callosobruchus maculatus (F.) and Sitophilus zeamais (Mots)

Insecticidal effects of different doses of the dust and methanol extracts of Garcinia kolae on Callosobruchus maculatus and Sitophilus zeamais were tested. The dust had no significant effect on the two insects, none of them died even at 3 d after treatment. The methanol extracts, however, had rapid lethal effects on both C. maculatus and S. zeamais. The mortality of C. maculatus by the lowest concentration of methanol extracts ranged from 95%-100% whereas in S. zeamais, the mortality ranged from 87.5%-100% and 70%-100% in concentrations of 1 g extract＋3 ml methanol and 1 g extract＋5 ml methanol, respectively, from 24 to 48 h. The least concentration of 1 g extract＋l 5 ml methanol had no significant lethal effect on Sitophilus zeamais.

Optimum Insecticide Doses Determination of Seed Oil of Three Botanicals Jatropha Curcas L., Helianthus Annus L. and Cocos Nucifera L. against Maize Weevil Sitophilus Zeamais Mots.

The insecticidal effect of four dosage rates of three botanicals namely Jatropha curcas, Heliathus annus and Cocos nucifera was tested on the maize weevil Sitophilus zeamais Mots.. This is done for the purpose of finding a replacement for conventional insecticides which has been found to be harmful to man. The seed oil was applied topically at the rate of 0.1, 0.2, 0.3 and 0.4 mL per insect. There were a total of 20 insects per Petri-dish. There were four replicates per treatment. Insect mortality was recorded on 12 hourly basis for 48 hours. The results of insects treated with all dosage rates of C. nucifera showed a significantly higher mortality when compared with the control. In the case ofH. annus, insect mortality ranged from 40-100, 70-100, 60-100 and 80-100% and for J. curcas the result ranged from 0.0-100, 40-100, 80-100 and 80-100% for rates of 0.1, 0.2, 0.3 and 0.4 mL, respectively, from 12 hrs to 48 hrs post application. The control experiment remained at 0% level throughout the period of the experiments.

Insecticidal Activity of the Powders Obtained from the Bauxite Red Mud, Zyzygium aromaticum and Citrus sinensis Peel Extracts on the Conservation of Corn against Sitophilus zeamais: Physicochemical Properties

The remarkable push of technologies increasingly recommends materials for their constructions.Hence the extraction of alumina is for different uses.The exploitation of bauxite pollutes the surrounding areas in this case the discharge of mud wheel.Furthermore,the excessive use of dangerous conventional synthetic insecticides continues to be in circulation in Cameroon despite the known adverse effects.These problems lead us to formulate bio insecticides from rejection of the extraction of alumina and extracts of S.aromaticum and Citrus sinensis which respectively offer us essential oils eugenol and limonene having insecticidal properties against the main insects,pests of corn stocks,Sitophilus zeamais.From the kinetic point of view of the adsorption of the extracts of eugenol,limonene and their association by the red mud,the adsorption curve shows that the Eu/Li mixture(30/70)is better by 0.36 mg/g during the 24 h.The results showed a high toxicity of the Eu-Li binary mixture of ratio 30/70 with respective mortality rates of 95.88%after 8 days of exposure to the concentration of 5 mL/L on the adults of Sitophilus zeamais.The other composites induce an average rate of 80%.The results from the physicochemical analysis of corn before and after treatment with formulated insecticides showed a slight loss in nutritional quality of 14.90%in ash,12.5%in protein,16.14%in lipids and 13.63%in total sugars for 180 days.The powdery formulation from red mud and Eu-Li(30/70)mixture can therefore ensure the protection of corn stocks against Sitophilus zeamais in a farming environment.

Interspecific Competition and Grain-Hosts Selection of Maize Weevil, <i>Sitophilus zeamais</i>(Motsch.) (Coleoptera;Dryophtoridae) and Larger Grain Borer, <i>Prostephanus truncatus</i>(Horn) (Coleoptera;Bostrichidae)

Laboratory interspecific competition and grain-hosts selection experiments involving maize weevil (MW), Sitophilus zeamais (Motsch.) and larger grain borer (LGB), Prostephanus truncatus (Horn) were performed under ambient temperature and relative humidity (25°C - 35°C and 70% - 80% relative humidity) in their major host cereal, maize grains. The species reproductive rate and grain-hosts preference were evaluated by a number of emerged adults. In combined infestation, both species competed intensively by simultaneously increasing their individuals’ emergence, 9-fold or greater than when reared alone. Even though both species simultaneously increased their progeny, S. zeamais was the dominant competitor and had a significant suppressant effect on P. truncatus. The selection result of grain-hosts showed that P. truncatus placed in the environment containing both uninfested maize grains and grains previously infested by S. zeamais, the insect prefers uninfested grains. Indeed, P. truncatus individuals’ emergences were significantly more important to uninfested grains than to infested grains. The weevil-infested grains seemed to have deterrent and detrimental effects on P. truncatus. Conversely, S. zeamais selection of grain-hosts was significantly (P = 0.0001) more attracted by P. truncatus infested grains than to uninfested grains. Sitophilus zeamais individuals’ emergences were significantly (P = 0.0008) more important to infested grains than to uninfested grains. The S. zeamais preference on grains previously infested would be stimulated by P. truncatus larval vibrations in grain.

米糠油对小麦中玉米象(Sitophihus Zeamais)的防治效果研究

通过米糠油对玉米象生物效应的实验室测定表明米糠油在不拌粮条件下，对玉米象有明显的引诱作用，引诱虫量与米糠油用量成正相关，在拌小麦条件下，对玉米象有明显的驱避作用，驱避率随米糠油用量的增加而上升，用量达１１．８ｍｌ／ｋｇ时，驱避率为９４．４％；当用量≥４ｍｌ／ｋｇ的米糠油拌粮时，对玉米象成虫有致死作用，用１６ｍｌ／ｋｇ拌粮时３－１０天后成虫死亡率达到７１．８－８５％；米糠油能抑制玉米象的繁殖，降低Ｆ１数量，当米糠油用量为４－８ｍｇ／ｋｇ时，玉米象繁殖抑制率为８８．１－９８．６％；米糠油对玉米象成虫无熏杀作用。

玉米象Sitophilus zeamais DNA条形码研究

【目的】玉米象Sitophilus zeamais(Motschulsky)为世界性分布仓储物害虫,食性极广,在我国多数省(区)均有分布。由于该虫与米象Sitophilus oryzae(Linnaeus)形态极似,很难区别;目前唯一可靠的鉴别特征是雌、雄外生殖器,且要实现准确鉴定必须要有成虫标本,还要经过一系列的繁琐操作,鉴定难度较大,因此需要探索更加便捷高效的鉴定技术。【方法】利用分子生物学手段,通过提取玉米象的基因组DNA,使用通用引物PCR扩增ITS1、ITS2、Cytb、COⅠ、COⅡ基因并测序,通过基因序列相似性来实现快速鉴定,进而获得用于快速鉴定的DNA条形码。【结果】通过形态特征,初步确定玉米象所属大致类群;通过分子生物学手段,获得了多个基因的碱基序列作为玉米象的DNA条形码。【结论】获得多条序列用来鉴定玉米象的DNA条形码,实现玉米象快速准确鉴定,为玉米象的识别鉴定提供基础数据。

Contact and fumigant toxicities of calamusenone isolated from Acorus gramineus rhizome against adults of Sitophilus zeamais and Rhizopertha dominica

Calamusenone [3,8-dimethyl-5-（1-methylethylidene）- 1,2,3,4,5,6,7,8-octa- hydroazulene-6-one, C15H22O] from Acorus gramineus Soland rhizome was tested in the laboratory for its insecticidal activities against adults of Sitophilus zeamais Motsch. and Rhizopertha dominica （Fab.）, using dry film contact and fumigation methods. Responses varied with insect species, dosage and exposure time. In the dry film contact experiment, the highest insecticidal effects of calamusenone against S. zeamais and R. dominica adults were produced at 170.32μg/cm2 after treatment for 72 h, with 96.2% and 98.7% mortalities, respectively. The median lethal concentration （LC50） （72 h） values of calamusenone against S. zeamais and R. dominica adults were 67.00 μg/cm2 and 77.30 μg/cm2, respectively. As a potential fumigant, calamusenone showed moderate insecticidal effect on the adults of S. zeamais and R. dominica in fumigation experiment, with their LC50 （120 h） values of 125.71μL/L and 93.64μL/L respectively. Calamusenone isolated from A. gramineus rhizome showed promise as a novel pesticide candidate for stored-product pest control.

感染隐蔽性害虫玉米象的稻谷、糙米和大米微环境中二氧化碳浓度变化

粮食中隐蔽性害虫早检早治可更好地避免粮食损失,明确粮堆中因害虫代谢产生的二氧化碳与稻米中隐蔽性害虫感染度的关系有助于隐蔽害虫快速检测。本研究分别以内含玉米象卵、1龄幼虫、2龄幼虫、3龄幼虫、蛹和粒内成虫的稻谷、糙米和大米按0、5、10头/kg和20头/kg密度混于无虫稻谷、糙米和大米中检测其中二氧化碳浓度。24 h时,无虫粮二氧化碳浓度仅为0.04%,含5、10头/kg和20头/kg卵和1龄幼虫的稻谷、糙米和大米中二氧化碳浓度为0.042%~0.055%;含2龄幼虫相应密度稻谷中二氧化碳浓度为0.127%、0.246%和0.425%,糙米中为0.145%、0.234%和0.483%,大米中为0.134%、0.246%和0.438%;含3龄幼虫相应密度稻谷中二氧化碳浓度为0.292%、0.425%和0.677%,糙米中为0.303%、0.482%和0.670%,大米中为0.292%、0.463%和0.668%;含蛹相应密度稻谷中二氧化碳浓度为0.095%、0.237%和0.381%,糙米中为0.082%、0.223%、0.430%,大米中为0.096%、0.235%和0.385%;含羽化成虫相应密度下稻谷中二氧化碳浓度为0.125%、0.215%、0.494%,糙米中为0.151%、0.235%、0.557%,大米中为0.131%、0.221%、0.503%。结果表明,稻谷、糙米和大米感染隐蔽虫态的玉米象24 h,环境二氧化碳浓度在0.15%以下为轻度感染(除蛹期外,此时玉米象多处于卵、1龄幼虫以及密度5头/kg及以下的2龄幼虫,为害虫发生初期或低密度感染状态),浓度为0.2%~0.4%时为中度感染(此时玉米象多处于2龄幼虫期,虫口密度10头/kg左右),浓度达0.55%以上时为严重感染(此时玉米象多处于3龄幼虫期,虫口密度20头/kg左右)。中度和严重感染时可在12 h检测到其显著变化。比较结果显示,糙米最容易被隐蔽的玉米象取食并产生较多气体,其次为大米和稻谷。

电子束处理对玉米象繁殖力的影响

本研究用电子加速器辐照处理玉米象成虫以及隐藏于小麦籽粒中的玉米象卵、幼虫和蛹 ,研究不同发育阶段玉米象辐照后的繁殖力。结果表明 ,高于 1 80Gy的辐照处理的成虫不能产生后代 ,辐照处理具有明显的当代延迟发育效果 ;高于 1 80Gy剂量辐照处理玉米象的蛹 ,羽化出的成虫不能产生下一代成虫 ;高于 90Gy以上的辐照处理玉米象的幼虫和卵 ,其羽化出的成虫不能产生下一代的成虫。 1 80Gy辐照可以作为阻止不同虫态玉米象的继续繁殖下一代的有效剂量。

水稻品种在贮藏期间对玉米象抗性的研究

对53份水稻品种进行了抗玉米象的筛选.根据敏感系数的差异,鉴定出抗级品种39份,中抗品种3份和敏感品种11份.并证实了应用自由选择和非自由选择的筛选方法,其趋势基本一致.敏感系数与谷粒的裂颖率呈极显著正相关,与米粒的粗蛋白、总淀粉、支链淀粉和直链淀粉含量及糊化温度无明显的相关性.

石菖蒲根茎甲醇提取物对玉米象和赤拟谷盗的生物活性

采用甲醇冷浸法和溶剂萃取法,研究了石菖蒲根茎提取物对玉米象和赤拟谷盗的触杀、熏蒸、忌避、种群抑制活性和防治效果。结果表明:石菖蒲甲醇提取物以石油醚萃取物的生物活性最强;石油醚萃取物对玉米象具有较好的触杀、忌避、种群抑制活性和防治效果,药膜法处理72h后对玉米象的LC50和LC95分别为38.54μg/cm2和160.70μg/cm2,滤纸药膜法39.30μg/cm2处理24h后的忌避率为83.83%,饲料拌药法1 000mg/kg处理后对玉米象的种群抑制率、防效与10mg/kg马拉硫磷处理效果差异均不显著;石油醚萃取物对赤拟谷盗具有很高的忌避活性,滤纸药膜法39.30μg/cm2处理72h后对其忌避率为91.17%。

无患子皂苷粗提物杀虫活性研究

[目的]为无患子皂苷应用于杀虫剂的开发提供理论依据,为开发利用云南省无患子属植物资源提供基础。[方法]通过浸渍法、饲料混药法、无限量取食法提取无患子中的皂苷,再进行对小菜蛾、玉米象、果蝇的室内毒力测定。[结果]无患子粗提取物皂苷对玉米象没有活性,对小菜蛾和果蝇有毒杀活性,但对果蝇的毒力较高,浓度为50.000mg/ml时,72h果蝇的死亡率为100%,72h对果蝇的LC为4.06mg/ml,浓度为25.000mg/ml时对果蝇的LT为30.19h。[结论]无患子皂苷可以作为植物源农药的材料而开发利用。

植物性杀虫剂防治玉米象的研究进展

本文系统介绍了各种植物性杀虫剂防治玉米象的研究方法,阐述了目前在玉米象防治中已利用的植物性杀虫剂的研究成果和应用价值。

电子束辐照谷物中玉米象不同虫态的生物效应

用ИЛУ 6М2 型电子加速器对玉米象成虫以及隐藏于小麦籽粒中的玉米象卵、幼虫和蛹进行辐照效应试验。结果表明 ,1 80Gy以上的剂量可以完全阻止谷物中幼虫和卵发育为成虫 ;在此剂量下有少量蛹可羽化为成虫 ,但存活力受严重影响 ,30 0Gy以上辐照的蛹即使羽化也在短时间内死亡 ;成虫被 30 0Gy的电子束辐照后寿命大缩短 ,在 1 4d内完全死亡。 30 0Gy电子束辐照剂量可以作为辐照有效防治玉米象的剂量。

苦皮藤素微粉剂对玉米中玉米象种群的控制

苦皮藤素微粉剂1和微粉剂2以不同的浓度混入玉米中,当使用剂量为1000mg/kg时,对玉米象成虫的种群繁殖抑制率分别为96.66%和96.02%,能有效控制玉米象成虫的危害,但对幼虫和卵的控制效果不明显。

巴豆提取物对玉米象的生物活性

研究了巴豆(Croton tigliumL.)4种溶剂提取物对玉米象Sitophilus zeamais(Motschulsky)成虫的驱避作用和触杀作用。结果表明:巴豆的4种溶剂提取物对玉米象Sitophilus zeamais(Mostchulsky)成虫均有很好的触杀作用,7.86 mg/cm2的浓度处理后,4 d后的校正死亡率均达到100%。巴豆的4种溶剂提取物对玉米象成虫没有明显的驱避作用。

辣根素对3种仓储害虫的熏蒸作用

在28℃环境温度下,利用三角瓶熏蒸法,测定了辣根素对3种仓储害虫的熏蒸毒力。结果表明,熏蒸48 h后,辣根素Ⅰ和辣根素Ⅱ对赤拟谷盗、谷蠹和玉米象成虫均具有明显的熏蒸效果。辣根素Ⅱ对3种仓储害虫的熏蒸效果均更好。辣根素Ⅰ熏蒸处理48 h后,对赤拟谷盗、谷蠹、玉米象成虫的毒力回归方程和LC50分别为:赤拟谷盗Y=-3.94+4.77X,6.68μL/L;谷蠹Y=-4.73+11.11X,2.67μL/L;玉米象Y=-4.22+7.47X,3.68μL/L。辣根素Ⅱ熏蒸处理48 h后,对赤拟谷盗、谷蠹、玉米象成虫的毒力回归方程和LC50分别为:赤拟谷盗Y=-4.17+5.65X,5.47μL/L;谷蠹Y=-1.82+5.39X,1.95μL/L;玉米象Y=-2.90+6.04X,3.02μL/L。