The role of vector control in stopping the transmission of malaria: threats and opportunities

Malaria control, and that of other insect borne diseases such as dengue, is heavily dependent on our ability to control the mosquito populations that transmit these diseases. The major push over the last decade to reduce the global burden of malaria has been driven by the distribution of pyrethroid insecticide-treated bednets and an increase in coverage of indoor residual spraying (IRS). This has reduced malaria deaths by a third. Progress towards the goal of reducing this further is threatened by lack of funding and the selection of drug and insecticide resistance. When malaria control was initially scaled up, there was little pyrethroid resistance in the major vectors, today there is no country in Africa where the vectors remain fully susceptible to pyrethroids. The first pyrethroid resistance mechanisms to be selected produced low-level resistance which had little or no operational significance. More recently, metabolically based resistance has been selected, primarily in West Africa, which in some mosquito populations produces more than 1000-fold resistance. As this spreads the effectiveness of pyrethroid-based bednets and IRS will be compromised. New public health insecticides are not readily available. The pipeline of agrochemical insecticides that can be re-purposed for public health dried up 30 years ago when the target product profile for agricultural insecticides shifted from broad spectrum, stable, contact-acting insecticides to narrow spectrum stomach poisons that could be delivered through the plant. A public–private partnership, the Innovative Vector Control Consortium, was established in 2005 to stimulate the development of new public health pesticides. Nine potential new classes of chemistry are in the pipeline, with the intention of developing three into new insecticides. While this has been successfully achieved, it will still take 6–9 years for new insecticides to reach the market. Careful management of the resistance situation in the interim will be needed if current gains in malaria control are not to be reversed.     

中国北方棉蚜对杀虫剂的抗药性(英文)

棉蚜(Aphis gossypu Glover)是我国北方棉区的主要害虫。自1953年开始使用有机磷杀虫剂对硫磷和1059等防治棉蚜以来,田间喷雾浓度和使用次数逐年增大,棉蚜产生的抗性。80年代使用高效拟除虫菊酯类杀虫剂溴氰菊酯和氰戊菊酯等,三年后棉蚜抗性增长了171倍,有些地区达3230倍。此文报道棉蚜的抗性机制的研究结果,证实了棉蚜抗性与杀虫剂穿透能力降低、多功能氧化酶、α-乙酸萘酯酶和α-乙酸萘酯羧酸酶的活力增加、乙酰胆碱酯酶对杀虫剂敏感性的降低有关。在这基础上进行增效剂SV_1对多种有机磷和拟除虫菊酯杀虫剂的增效试验,得出SV_1对防治抗性棉蚜有明显的增效作用,能延缓抗性的发展。并研究了杀虫剂抗性的防治策略及综合治理措施,为防治棉蚜抗性和延缓抗性发展取得了较好的效果。     

中国丽叩甲属的新种新纪录（鞘翅目：叩甲科）

丽叩甲属Campsosternus是叩甲科中较大形而且十分美丽的一个类群,全身具有明亮的金属光泽,很易识别。该属由法国Latreille 1834年建立,属模种为C.auratus(Drury);在此之前,所发表的丽叩甲种类大多归属在当时的叩甲属Elater中。十九世纪下半叶法国学者Candeze在他的叩甲专著中将这个类群归属在绒鳞叩甲族Chalcolepidiides中,大多数学者沿用了这一系统,并进行了适当的调整,将绒鳞叩甲族上升为绒鳞叩甲亚科Chalcolepidiinae。Fleutiaux 1927年将丽叩甲属从绒鳞叩甲亚     

INSECTICIDE RESISTANCE OF COTTON APHID IN NORTH CHINA

Abstract  The cotton aphid ( Aphis gossypii Glover) is one of the most important pests infesting cotton in the cotton areas of North China. Since 1953 organophosphorus insecticides such as parathion and systox have been used to control the aphids for keeping up good yield of cotton. After several years. the concentration and the amount of spray were increasing in the field. In the early 1980's highly effective pyrethroid insecticides such as decis and sumicidin were largely imported into China. When first used 2. 5% decis emulsion was diluted in the ratio from 1:10000 to 1: 12000. However in 1985 the resistance of cotton aphid to pyrethroids increased by 171 times in general, 3230 times in some cotton fields. Thus it has prompted us to investigate the mechanism of resistance to insecticides and to search for the strategy to control the resistant aphids.
Experiments showed that the use of synergists including SV₁ (O, O-diethyl, O-phenyl phos-phorothionate) and PB has given evidence indicating mixed function oxidases (MFO). α-NA esterases and α-NA carboxylesterase are involved in the formation of resistance. The results also showed that the sensitivity of AChE to paraoxon in resistant aphids was lower than that in susceptible aphids.
Experiments showed that SV₁ was particularly synergistic to organophosphorus or pyrethroid insecticides and had played an excellent role in overcoming the resistance of cotton aphids to insecticides.     

五种槽缝叩甲超微形态结构的比较研究 (鞘翅目:叩甲科)

通过扫描电镜观察了槽缝叩甲属Agrypnus 5种的触角、前胸背板、中胸小盾片、鞘翅、前胸腹板、前胸侧板、中胸腹窝、跗节等部位的超微形态结构,提出了5种槽缝叩甲超微形态的区别特征,发现了槽缝叩甲体表鳞片毛上的纵脊数目和走向、中胸腹窝的结构与形状、体表刻点的形态等具有明显的种间差异,具有重要的分类学意义。讨论了硬结构昆虫扫描样品制备的程序,叩甲的叩头关节、触角槽、跗节槽的形成与功能,以及超微形态结构在叩甲分类上的价值等。     

几种拟除虫菊酯类杀虫剂对美洲斑潜蝇的防治效果

测定了拟除虫菊酯类农药功夫、灭扫利、速灭杀丁和兴棉宝对美洲斑潜蝇各龄幼虫、雌成虫的毒力以及对成虫取食、产卵的影响,并进行了田间小区试验。结果表明：美洲斑潜蝇一、二、三龄幼虫和雌成虫对功夫最敏感,一、二、三龄幼虫对功夫的 ＬＣ５０分别是 ０．００７５、０．００９３、０．０１１２ ｇ（ａ．ｉ．）／Ｌ,雌成虫对功夫的 ２４小时、４８小时的 ＬＣ５０分别是０．００２７、０．００２５ ｇ（ａ．ｉ．）／Ｌ。功夫对美洲斑潜蝇的取食、产卵拒避持效期分别是 ４天和 ６天,用浓度 ０．０２５ ｇ（ａ．ｉ．）／Ｌ的功夫药液处理 ０、２、４、６天后接虫,幼虫存活率分别是０、６．３％、６．８％和 ６１．６％,田间用浓度 ０．０２５、０．０１６７ ｇ（ａ．ｉ．）／Ｌ功夫分别处理,６天的校正虫口减退率分别是９１．９６％和８３．６０％。     

Mortality and knockdown effects of imidacloprid and methomyl in house fly (Musca domestica L., Diptera: Muscidae) populations

In this study, the knockdown and mortality effects of imidacloprid and methomyl were investigated. The residual surface applications were carried out to determine the knockdown effects (KDt₅₀ and KDt₉₅) and mortality (LD₅₀ and LD₉₅) induced by each insecticide. For mortality comparisons, the susceptible house fly (Musca domestica L., Diptera: Muscidae) of a WHO population and three natural field‐collected M. domestica populations from Turkey were used. In conclusion, it was found that the resistance to imidacloprid and methomyl was significantly higher in the field populations when compared to the susceptible population from WHO. The results showed that applicators and pest management decision‐makers should control and conduct an integrated pest management strategy by including biological agents to prevent the development of high levels of resistance in the field populations.     

Pyrethroid resistance in Culex quinquefasciatus from West Africa

Laboratoire de Lutte contre les Insectes Nuisibles, ORSTOM, Montpellier, France, *OCCGE, Institut Pierre Richet, BP 1500, Bouaké 01, Côte d'Ivoire, †INRA, Laboratoire de Biologie des Invertébrés, 123 Bd Meilland, 06606 Antibes, France, and ‡CNRS UMR 5554, Laboratoire de Génétique et Environnement, Institut des Sciences de l'Environnement, Université de Montpellier II (CC 065), 34095 Montpellier, France
Abstract .Pyrethroid resistance was investigated in thirty-three samples of Culex quinquefasciatus Say from twenty-five cities in Côte d'Ivoire and Burkina Faso. Permethrin resistance ratios at LC₅₀ ranged from 9.5- to 82-fold in Côte d'Ivoire and from 17- to 49-fold in Burkina Faso. For deltamethrin, resistance ratios were lower and ranged from nine to thirty-eight in both countries. A strain was selected with permethrin to investigate resistance mechanisms. After forty-two generations of selection, permethrin resistance level reached 3750-fold, but deltamethrin resistance remained unexpectedly unchanged. This indicated that a specific mechanism was involved in permethrin resistance. Synergist assays and biochemical tests indicated that resistance was partly due to P450-dependent oxidases. A target site insensitivity ( kdr ) was also involved, associated with DDT cross resistance and a dramatic loss of permethrin knockdown effect on adults. This resistance should be taken into consideration when planning the use of pyrethroid-impregnated materials in urban areas, as Culex is by far the main source of nuisance. Any failure in nuisance control due to resistance is likely to demotivate people in using impregnated materials.