Haematological effects of apholate in the red cotton bug,Dysdercus koenigii

Topical application of sterilizing doses of apholate causes haematological changes in the adults ofDysdercus koenigii. The normal males have less haemolymph (13–16 l) than females (18–37 l) for the first 120 hr of adult life. Apholate treatment significantly reduces the haemolymph volume of both the sexes. There are significantly more haemocytes in circulation in adult females than in males. The total haemocyte count shows an initial increase up to 48 hr, but later indicates a drastic reduction in the treated males and females. The plasmatocytes of the treated insects are found to reduce in numbers and the prohaemocytes become the predominant type, while in controls the plasmatocytes are the major type of haemocytes.

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Zusammenfassung Topicale Anwendung von sterilisierenden Dosen von Apholat verursacht hämatologische Änderungen bei den Adulten vonDysdercus koenigii. Die normalen Männchen haben weniger Hämolymphe (13–16 l) als Weibchen (18–37 l) in den ersten 120 h des adulten Lebens. Apholatbehandlung reduziert signifikant das Hämolymphvolumen beider Geschlechter. Es sind signifikant mehr Hämocyten im Umlauf bei adulten Weibchen als bei Männchen. Zählung der Gesamthämocyten zeigt bei behandelten Männchen und Weibchen ein anfängliches Anwachsen bis zu 48 h, später aber eine drastische Reduktion. Die Zahl der Plasmatocyten der behandelten Insekten erwies sich als abnehmend und die Prohämocyten werden der überwiegende Typ, während in der Kontrolle die Plasmatocyten der Haupttyp der Hämocyten sind.

     

Azadirachtin: I-interaction with the development of red cotton bugs

Azadirachtin, a material isolated from Azadirachta indica A. Juss, was applied to various stages of red cotton bugs (Dysdercus koenigii F.). The phytochemical evoked various specific and nonspecific effects during the course of development. Prolonged development, wing deformities unplasticisation of wing lobes, development of wingless adults and larval mortality were the characteristic features.

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Azadirachtine d'Azadirachta indica I: Interaction avec de développement de Dysdercus koenigii

Résumé L'azadirachtine, isolat de Azadirachta indica A. Juss a été utilisée (par traitement du substrat ou par dépôt sur l'insecte) sur un hétérométabole, Dysdercus koenigii F. Cette substance phytochimique provoque divers effets, spécifiques ou non, pendant le développement.Les modifications caractéristiques sont: un développement prolongé, de déformations alaires, une absence de plastification des bourgeons alaires, une production d'adultes sans ailes et une mortalité nymphale.De tels résultats suggèrent des études complémentaires pour mettre en évidence une hormone d'éclosion chez D. koenigii avec laquelle interférerait l'azadirachtine.

     

Amino acid requirements of the cotton stainer, Dysdercus fasciatus (Pyrrhocoridae, Hemiptera)

L-glutamic acid-¹⁴C (U.L.) injection provided a convenient means for the study in vivo of the amino acid requirements of Dysdercus fasciatus. The production of ¹⁴CO₂ by the injected insects indicated that glutamic acid was metabolized by the Dysdercus system.Out of the 16 amino acids extracted from the treated insects, arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophane and valine carried a negligible amount of radioactivity, while alanine, aspartic acid, glycine, proline, serine and tyrosine had a very high level of radioactivity.On the basis of these studies, it would appear that the amino acids which had low radioactivity levels are essential, while those carrying high amounts of radioactivity are not essential for the normal growth of Dysdercus.

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Résumé L'injection de l'acide glutamique 14 C (U. L.) a constitué un moyen satisfaisant pour l'étude in vivo des besoins en acides aminés de Dysdercus fasciatus. La production de ¹⁴CO² par les insectes injectés a montré que l'acide glutamique était métabolisé par Dysdercus.Parmi les 16 acides aminés extraits des insectes traités, l'arginine, l'histidine, l'isoleucine, la leucine, la lysine, la méthionine, la phénylalanine, la thréonine, le tryptophane et la valine ont présenté un taux négligeable de radioactivité; tandis que l'alanine, l'acide aspartique, la glycine, la proline, la sérine et la tyrosine ont un très haut degré de radioactivité.Sur la base de ces études il apparaîtrait que les acides aminés qui ont des taux de radioactivité faibles sont essentiels à la croissance normale de Dysdercus, tandis que ceux qui présentent des taux élevés de radioactivité ne sont pas essentiels.

     

Genetic diversity within and among the wild populations of Murraya koenigii (L.) Spreng., as revealed by ISSR analysis

Murraya koenigii (L.) Spreng., commonly known as curry leaf plant, is found in the different hilly regions of India. In the present study, fifty-nine accessions representing eight wild populations of M. koenigii were analyzed using thirteen ISSR primers. A total of 152 bands were amplified, out of which, 136 were polymorphic corresponding to 89.47% polymorphism across the accessions. The pairwise population genetic distances were calculated for all the populations that varied from 0.05 to 0.13 between the populations of M. koenigii. AMOVA and Nei’s genetic diversity analysis revealed higher genetic variations within populations than among the populations. The clustering of populations in the dendrogram was not in congruence with geographical affiliations. The results indicate that the ISSR method is sufficiently informative and powerful to estimate the genetic diversity in M. koenigii populations. As M. koenigii is an important wild plant genetic resource, therefore, information on genetic variability might be a potential source as breeding material for development of commercially valuable traits in M. koenigii plants.     

Anti-trichomonal, biochemical and toxicological activities of methanolic extract and some carbazole alkaloids isolated from the leaves of Murraya koenigii growing in Nigeria

The methanolic extract of Murraya koenigii leaf was screened for toxicological and biochemical effects on rats because of the folkloric uses as an anti-dysentery and anti-diabetes. The extract was moderately toxic (LD(50)=316.23 mg/kg body weight) to rats and had appreciable effect on the liver and kidney at higher doses leading to liver inflammation. It had little or no effect on haematology and relative organ weight of lungs, heart and spleen. Acute doses (500 mg/kg) reduced significantly serum globulin, albumin, urea, glucose, total protein, aspartate transaminase (AST), and increased cholesterol and alanine transaminase (ALT) indicating hepatic injury. However, chronic administration for 14 days gave a significant (p<0.05) reduction in the serum cholesterol, glucose, urea, bilirubin, ALT and AST showing that the plant has hypoglycaemic and hepatoprotective effects after prolonged use. The activity demonstrated by some of the isolated carbazole alkaloids and their derivatives against Trichomonas gallinae confirmed that the anti-trichomonal activity of the leaf may be due to its carbazole alkaloids. The order of activity was C(18)>C(23)>C(13). Girinimbine and girinimbilol with IC(50) values of 1.08 and 1.20 microg/ml were the most active. Acetylation of girinimbilol and mahanimbilol improved their activities to 0.60 and 1.08 microg/ml.     

转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响

【目的】为探究转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育及其捕食功能的影响。【方法】以转Cry1Ac/1Ab基因棉与其亲本常规棉为实验材料,利用取食不同棉花品种叶片的棉铃虫饲喂异色瓢虫幼虫。【结果】与常规亲本棉相比,取食饲喂转基因棉花叶片的初孵棉铃虫幼虫的异色瓢虫幼虫从1龄发育至化蛹期时间延长0.77 d,但差异不显著;除1龄幼虫体重增加(0.0773 mg)外,其余各龄期幼虫体重均有所下降,但差异均不显著;异色瓢虫1、2、3、4龄幼虫对初孵棉铃虫捕食量均随棉铃虫密度的增加而增加,捕食功能反应均符合HollingⅡ圆盘方程。【结论】转Cry1Ac/1Ab基因棉花对异色瓢虫生长发育无显著影响,饲喂取食转Cry1Ac/1Ab基因棉花的棉铃虫对异色瓢虫捕食功能无显著差异。     

家蚕BmAKR基因家族的鉴定及在蚕卵中的表达分析

醛酮还原酶超家族(aldo-keto reductase super family,AKRs)具有广泛的底物特异性,目前尚未见对昆虫AKR基因家族成员的系统鉴定报道。本研究采用生物信息学手段,预测了家蚕(Bombyx mori) AKR基因的系统进化、理化性质、染色体定位、保守基序和基因结构,通过转录组数据和实时荧光定量聚合酶链式反应(quantitative real time polymerase chain reaction,q RT-PCR)分析了不同组织时期及不同发育状态蚕卵中Bm AKR基因的表达水平,并采用Western blotting检测了蚕卵中该蛋白的表达量。本研究共鉴定出11个Bm AKR基因,分布在4条不同的染色体上,都具有AKR家族特有的(α/β) 8桶保守结构,理化特征较为相似;系统进化分析显示,其可分为2个家族(AKR1和AKR2)。转录组数据分析显示,家族成员基因在不同组织时期中的表达差异较大。进一步分析发现,一部分Bm AKR基因在非滞育卵的表达量显著高于滞育卵;但Bm AKR1-1在滞育卵中的表达量却显著高于非滞育卵。蛋白水平的检测发现Bm AKR1...     

转RRM2基因棉和其亲本苗蚜种群数量及其优势天敌的动态规律

【目的】转基因作物的大规模种植,可能会对人类健康和生态环境造成影响。因此,商业化种植之前,评价环境安全性十分必要。【方法】以转基因(RRM2)高产棉为实验品种,受体材料中棉所12为对照品种,分别于2013年和2014年连续2年对2种棉田的苗期蚜虫及其几种主要捕食性天敌的田间种群数量进行系统的田间调查,并比较它们在这2种不同棉田间的差异。【结果】与中12相比,转RRM2基因棉苗期无翅蚜的发生数量显著增加,有翅蚜迁入棉田的数量也有所增加,但二者差异不显著;2个棉花品系间棉蚜的几种主要捕食性天敌发生数量也无明显差异。【结论】与亲本材料相比,转高产棉花苗蚜数量显著增加,但其捕食性天敌数量增加不明显。本研究为转RRM2高产基因棉花环境安全评价技术的完善提供了理论依据。     

Interspecific competition betweenEupelmus vuilleti andDinarmus basalis, two solitary ectoparasitoids ofBruchidae larvae and pupae

Coexistence of two solitary ectoparasitoids of bruchids may be the result of counter-balanced competition. Some strategies in interspecific competition at the extrinsic level of female behaviour are identified.Dinarmus basalis (Rondani) (Hymenoptera; Pteromalidae) has adapted an evasion strategy to avoid competition. Females ofD. basalis show interspecific discrimination against hosts parasitized byEupelmus vuilleti Crawford (Hymenoptera; Eupelmidae) and lay fewer eggs in the presence of females or hosts parasitized by the latter.Eupelmus vuilleti has adapted an aggressive strategy. In contrast toD. basalis, E. vuilleti concentrates her ovipositions on hosts already parasitized byD. basalis. Females ofE. vuilleti preferably use oviposition holes made by other parasitoids, and are able to kill eggs and larvae ofD. basalis selectively by thrusts of their ovipositor (ovicide and larvicide). Furthermore,E. vuilleti can act as a facultative hyperparasitoid on older larvae ofD. basalis. The number ofE. vuilleti offspring is not affected by the presence ofD. basalis on a host. Our study does not provide insight in the process of larval competition.

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Résumé La coexistence de deux ectoparasito?des solitaires de Bruchidés peut resulter de compétition contrebalancée (Zw?lfer, 1971). Quelques stratégies en situation de compétition interspécifique ont été indentifiées au niveau (extrinsèque) du comportement de femelles.Dinarmus basalis (Rondani) (Hymenoptera; Pteromalidae) a développé une stratégie d'évitement de la compétition. Les femelles deD. basalis montrent une capacité à reconna?tre les h?tes parasités parEupelmus vuilleti Crawford (Hymenoptera; Eupelmidae), et pondent moins d'œufs en présence des femelles d'E. vuilleti ou des h?tes parsités par cette espèce.Eupelmus vuilleti a adapté une stratégie aggressive. Au contraire deD. basalis, E. vuilleti concentre sa ponte sur les h?tes déjà parasités parD. basalis. Les femelles d'E. vuilleti utilisent préférentiellement les orifices de ponte pratiqués par les autres parasito?des. Elles sont alors capables de tuer grace à l'ovipositeur les œufs et les larves deD. basalis (ovicide et larvicide). De plus,E. vuilleti est capable d'hyperparasiter les larves de dernier stade deD. basalis. Le nombre de descendants d'E. vuilleti n'est pas affecté par la présence deD. basalis sur un h?te. Notre étude expérimentale n'a pas permis l'étude du mécanisme de la compétition larvaire.

     

转Cry1Ac+Cry2Ab基因棉花主要生化物质含量变化及其对棉田昆虫的影响

【目的】新型转基因棉花在进入大规模商业化应用前,需对其生态环境安全性进行评价;同时,经基因改造的新型转基因抗虫棉花可能影响抗虫棉的次生代谢,进而导致一些综合的生态学效应,致使棉花生理上发生改变,这也是转基因植物安全性评价研究的重要内容。【方法】比较了不同关键时期新型转Cry1Ac+Cry2Ab基因棉花与转Cry1Ac基因棉花和非转基因棉花叶片的鲜重、干重和干鲜比、主要酶[超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)]活性、营养物质(蛋白质、氨态氮、脯氨酸和可溶性糖)和次生代谢产物(棉酚和单宁)含量的差异及其对棉田不同昆虫营养层昆虫个体总数和物种数的影响。【结果】棉花生长的蕾期、花期和花铃期,转Cry1Ac+Cry2Ab基因棉花、转Cry1Ac基因棉花和非转基因棉花叶片的鲜重、干重和干鲜比呈先升高后降低的趋势;SOD和POD活性在花铃期明显升高,CAT、APX和GR活性无显著变化;蛋白质、氨态氮含量无明显变化,脯氨酸和可溶性糖含量均表现为先升高后下降的趋势;棉酚含量在3个时期无显著变化,而单宁含量呈逐渐升高的趋势。3种棉花叶片中干物质积累、主要酶活性、营养物质和次生代谢产物含量均无显著差异;单株大铃数表现为转Cry1Ac+Cry2Ab基因棉花转Cry1Ac基因棉花非转基因棉花,小铃数则表现为转Cry1Ac基因棉花Cry1Ac+Cry2Ab基因棉花非转基因棉花;昆虫群落和害虫亚群落的昆虫个体总数均表现为转Cry1Ac+Cry2Ab基因棉田转Cry1Ac基因棉田非转基因棉田,天敌亚群落昆虫个体总数无显著变化;3种棉田中昆虫群落、害虫亚群落和天敌亚群落的物种数均未发生显著变化。【结论】转Cry1Ac+Cry2Ab基因棉花叶片干物质积累、产量性状、生化物质含量、酶活性在不同生长期表现不同,但上述参数在3种棉花之间无显著差异;且转Cry1Ac+Cry2Ab基因棉花具有较好的抗虫性,能有效降低棉田害虫数量。     

番茄潜叶蛾对不同类型杀虫剂的敏感性

【目的】番茄潜叶蛾是一种对番茄具有毁灭性危害的世界入侵害虫,本研究测定了不同类型药剂对入侵害虫番茄潜叶蛾的毒力活性及防治效果,为生产中科学防治番茄潜叶蛾提供理论依据。【方法】采用室内毒力测定方法,计算各药剂对不同龄期幼虫的毒力回归方程;采用田间防效评价方法,得出药后1~21 d各药剂对幼虫的防效,综合比较分析不同类型药剂对番茄潜叶蛾的控制作用。【结果】室内毒力测定结果表明,植物源杀虫剂印楝素和抗生素类杀虫剂甲氨基阿维菌素苯甲酸盐对番茄潜叶蛾的毒性相对最强,其中印楝素对1龄幼虫的毒力最强,其LC₅₀为3.22 mg·L^-1,甲氨基阿维菌素苯甲酸盐对2~4龄幼虫的毒力最强,其LC₅₀分别为7.1046、7.5663和4.375 mg·L^-1;其次是苯甲酰脲类杀虫剂氯虫苯甲酰胺和合成杀虫剂乙基多杀菌素;拟除虫菊酯类杀虫剂高效氯氰菊酯、昆虫生长调节剂类杀虫剂甲氧虫酰肼对番茄潜叶蛾也有较好的毒杀作用;新烟碱类杀虫剂吡虫啉、噻虫嗪、烯啶虫胺对番茄潜叶蛾的毒性相对较弱。田间防效结果表明,抗生素类杀虫剂甲氨基阿维菌素苯甲酸盐的防效相对最高、持效性最好,药后第7、14和21天防效分别为74.11%、71.42%和60.03%;其次是苯甲酰脲类杀虫剂氯虫苯甲酰胺、合成杀虫剂乙基多杀菌素和拟除虫菊酯类杀虫剂高效氯氰菊酯;植物源杀虫剂印楝素的持效性较好,药后第7~21天的防效均高于50%;昆虫生长调节剂类杀虫剂甲氧虫酰肼以及新烟碱类杀虫剂吡虫啉、噻虫嗪、烯啶虫胺对番茄潜叶蛾的田间防效相对较弱。【结论】抗生素类杀虫剂甲氨基阿维菌素苯甲酸盐、苯甲酰脲类杀虫剂氯虫苯甲酰胺和合成杀虫剂乙基多杀菌素可作为生产中防治番茄潜叶蛾的首选药剂,具有较好的应用前景,植物源杀虫剂印楝素和拟除虫菊酯类杀虫剂高效氯氰菊酯可作为交替使用药剂。     

Cloning, sequence analysis and crystal structure determination of a miraculin-like protein from Murraya koenigii

Earlier, the purification of a 21.4 kDa protein with trypsin inhibitory activity from seeds of Murraya koenigii has been reported. The present study, based on the amino acid sequence deduced from both cDNA and genomic DNA, establishes it to be a miraculin-like protein and provides crystal structure at 2.9 Å resolution. The mature protein consists of 190 amino acid residues with seven cysteines arranged in three disulfide bridges. The amino acid sequence showed maximum homology and formed a distinct cluster with miraculin-like proteins, a soybean Kunitz super family member, in phylogenetic analyses. The major differences in sequence were observed at primary and secondary specificity sites in the reactive loop when compared to classical Kunitz family members. The crystal structure analysis showed that the protein is made of twelve antiparallel β-strands, loops connecting β-strands and two short helices. Despite similar overall fold, it showed significant differences from classical Kunitz trypsin inhibitors.     

不同生物药剂对稻水象甲的毒力、拒食活性及防效分析

【目的】防治稻水象甲的现有常规化学药剂的大量施用所引发的环境问题越发突出,而其生物药剂单一,加之天敌匮乏,故开展符合绿色生产标准的低毒、低残留、无污染生物药剂的筛选已成为稻水象甲防治工作所面临的首要任务。【方法】以越冬代稻水象甲成虫为试虫,采用室内点滴、田间喷雾等方法,对5种符合绿色生产标准药剂的毒力、拒食活性、防效及药后取食量等指标进行了测定和综合评价。【结果】室内生测方面:72 h后对处理稻水象甲成虫的室内毒力显著;此外,对试验前后的取食斑面积进行比较,发现药后各药剂拒食活性差异显著,均表现出较好的拒食作用。田间药效方面:除0.6%苦参碱AS外,其他药剂对稻水象甲均表现出较好的防效,100亿个孢子·m L~(-1)白僵菌OD、1.5%除虫菊素AS、7.5%鱼藤酮EC和6%乙基多杀菌素SC这4种药剂15 d的田间防效为51.24%~82.55%;3 d后各处理组田间新增取食斑数、取食长度均显著低于对照组。【结论】在绿色水稻生产中,100亿个孢子·m L~(-1)白僵菌OD、1.5%除虫菊素AS、7.5%鱼藤酮EC和6%乙基多杀菌素SC均具有较好的推广价值,可用于稻水象甲的防治。     

Encarsia formosa parasitizing the Poinsettia-strain of the cotton whitefly,Bemisia tabaci, on Poinsettia: bionomics in relation to temperature

Adult longevity, developmental time and juvenile mortality ofEncarsia formosa Gahan (Hymenoptera:Aphelinidae) parasitizing the Poinsettia-strain ofBemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on Poinsettia (Euphorbia pulcherrima Willd.) were investigated in laboratory experiments at three temperatures: 16 °C, 22 °C and 28 °C. Furthermore, the parasitoid's preference for different larval stages of the whitefly was determined at 24.5 °C. The lifespan ofE. formosa decreased with temperature from one month at 16 °C to nine days at 28 °C. A lower temperature threshold of 11 °C for adult development was found. The development of juvenile parasitoids inB. tabaci lasted more than two months at the lowest temperature, but was only 14 days when temperature was 28 °C. The lower temperature threshold for immature development was 13.3 °C, yielding an average of 207 day-degrees for the completion of development into adults. Juvenile mortality was high, varying from about 50% at 16 °C to about 30% at 22 °C and 28 °C.E. formosa preferred to oviposit in the 4th instar and prepupal stages ofB. tabaci followed by the 2nd and 3rd instars. The preference for the pupal stage was low. The parasitoid used all instars of the whitefly for hostfeeding, with no apparent differences between the stages. The average duration of the oviposition posture was four minutes. Demographic parameters were calculated from life tables constructed from the data. The intrinsic rate of increase (r _m) and the net reproductive rate (R ₀) increased with temperature from 0.0279 day⁻¹ at 16 °C to 0.2388 day⁻¹ at 28 °C and from about 12 at 16 °C to about 66 at 28 °C, respectively.     

Temperature dependent functional response ofEncarsia formosa parasitizing the Poinsettia-strain of the cotton whitefly,bemisia tabaci, on Poinsettia

The control efficiency and performance ofEncarsia formosa Gahan (Hymenoptera: Aphelinidae) as influenced by the density of its host, the Poinsettia-strain ofBemisia tabaci Gennadius (Homoptera: Aleyrodidae), were investigated by laboratory experiments on Poinsettia (Euphorbia pulcherrrima Willd.).E. formosa showed a Type II functional response to fourth instar larvae ofB. tabaci, the response plateau increasing with temperature. A response model for randomly searching parasitoids incorporating temperature-dependent handling time and temperature-independent search rate was in accordance with the results, and gave an estimated search rate of 0.033 leaf·hour⁻¹ and handling times of 1.54, 2.86 and 20.1 h at 28°C, 22°C and 16°C, respectively. From the latter, the maximum number of hosts that can be parasitized at the three temperatures are 10.4, 5.6 and 0.8 larvae per day (provided the light period is 16 h). The number of hosts with ovipositor punctures was higher than the number of parasitized hosts, especially at 22°C and 28°C, implying thatE. formosa refrains from laying eggs in some of the hosts examined with the ovipositor. About 31% of the punctured larvae did not contain any eggs. Superparasitism occured during the experiment presumably originating from young, inexperienced parasitoids. Individual larvae were occasionally punctured several times, also by non-superparasitizingE. formosa. The resulting distribution of ovipositior holes was random, indicating thatE. formosa on the basis of antennal testing is unable to determine if a larva has previously been examined with the ovipositor. Almost fifty percent of the punctures were not followed by egg-depositions. Besides parasitizationE. formosa used hosts as food source. The number of hostfed larvae was independent of density, but varied with temperature being highest at 28°C (0.12 hostfed larvae per parasitoid per day).     

连作对棉花抗枯萎病生理生化特性的影响

连作障碍引起棉花的产量和品质下降,严重制约着我国棉花产业的可持续发展。枯萎病作为典型的土传真菌病害,一直是困扰我国棉花生产的两大病害之一。研究采用室内盆栽试验,通过接种棉花枯萎病菌,研究不同连作年限(0、5、15a)土壤对棉花生长状况及体内超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、可溶性蛋白和丙二醛(MDA)含量的影响,进而探讨其对棉花抗枯萎病性能的影响。研究结果表明:与非连作土壤相比,连作土壤显著影响棉花的生长,导致棉花幼苗鲜重、主根长、株高降低,SOD和CAT活性降低,可溶性蛋白和丙二醛(MDA)含量升高,抗病品种中棉38的POD活性无显著变化,但耐病品种南农10号的POD活性明显提高。说明连作降低了棉花对枯萎病菌的抗氧化酶反应,加重了棉花的膜质过氧化程度,进而降低了棉花对枯萎病的抗性。     

不同杀虫剂对锡兰玻壳蚧的室内毒力及田间防效

【目的】锡兰玻壳蚧是我国余甘子上新发现的重要害虫,对农业生产及生态安全构成严重威胁。本研究旨在筛选出高效理想的防治药剂,为生产中科学用药提供依据。【方法】采用浸渍法测定8种杀虫剂对锡兰玻壳蚧的室内毒力,采用喷雾法评价5种毒力较好药剂的田间防效。【结果】室内毒力测定结果表明:毒死蜱、啶虫脒、吡虫啉、阿维菌素、甲维盐对1、2龄若虫的毒力较强,48 h致死中浓度(LC₅₀)分别为11.1245、26.2376 mg·L^-1,17.5381、26.1910 mg·L^-1,27.5896、34.2868 mg·L^-1,26.5876、38.8034 mg·L^-1,29.0528、43.0443 mg·L^-1;毒死蜱和阿维菌素对3龄若虫、雌成虫的毒力较强,48 hLC₅₀分别为87.3427、495.8339 mg·L^-1,95.4751、1131.6430 mg·L^-1;螺虫乙酯、吡丙醚和高效氯氟氰菊酯对各虫期的毒力均较弱;吡虫啉、阿维菌素、啶虫脒、甲维盐对各龄若虫的毒力比差异较小,毒死蜱的毒力比差异较大,但后者对各龄若虫的毒力均较强。田间防效结果表明:毒死蜱和阿维菌素对田间种群增长抑制效果最好,药后7 d防效分别为96.90%、92.00%;吡虫啉、甲维盐和啶虫脒对低龄若虫种群速杀效果较好,药后7 d防效分别为78.06%、67.62%、62.78%。【结论】锡兰玻壳蚧的化学防治应于1~2龄若虫期进行,推荐阿维菌素、毒死蜱、吡虫啉、甲维盐和啶虫脒轮换使用;3龄雌若虫及雌成虫盛发期推荐使用毒死蜱和阿维菌素防治。     

棉花枯萎病菌突变体库的构建及分析

[背景]棉花枯萎病逐渐成为威胁新疆海岛棉产业发展的主要病害,但关于棉花枯萎病菌的致病力、产孢量、生长速度及颜色变化等相关功能基因目前还不是十分明确.[目的]通过构建绿色荧光蛋白(green fluorescent protein,GFP)标记棉花枯萎病菌突变体库,筛选出由于T-DNA的随机插入而导致性状发生变异的突变体...     

Studies on the isolation of plumbagin from in vitro and in vivo grown Drosera species

The rapid clonal multiplication of two species of South African Drosera is described. Levels of plumbagin, (5-hydroxy-2-methyl-1,4-naphthoquinone) from in vivo and in vitro grown plants are compared to those present in Plumbago roots. P. auriculata Lam. roots contained more than twice as much plumbagin as in vivo grown D. capensis L. plants which in turn contained more than twice as much as comparable plants of D. natalensis Diels. It is concluded that the extraction of plumbagin from Drosera plants is not commercially feasible.