Cypermethrin inhibits egg development in the ixodid tick, Amblyomma hebraeum

The pyrethroid insecticide, cypermethrin (CyM), stimulates vitellogenesis in Ornithodoros moubata (an argasid tick) by stimulating the release of the normal vitellogenesis-inducing factor (a neuropeptide) and subsequent release of the vitellogenic hormone [19]. Here we examine the effects of CyM on egg development in the ixodid tick, Amblyomma hebraeum. Ovary weight, oocyte size, and vitellin content of the ovary were measured after CyM treatment; in partially fed ticks, none of these parameters were affected significantly. However, CyM treatment caused an inhibition of ovary development, as well as reduction of both hemolymph 20-hydroxyecdysone (20E; the vitellogenic hormone in this species) and vitellogenin (Vg)-concentrations in engorged ticks. In addition, the degree of salivary gland degeneration (which is triggered by 20E) was slightly reduced in CyM-treated engorged ticks. These results indicate that CyM acts differently in Amblyomma compared to Ornithodoros. Instead of stimulating vitellogenesis, CyM inhibits egg development perhaps in part as a result of inhibiting release of 20E.     

Tsetse control in cattle from pyrethroid footbaths

In Burkina Faso, we assessed the efficacy of treating cattle with a footbath containing aqueous formulations of pyrethroids to control two tsetse-fly species, Glossina tachinoides Westwood, 1850 (Diptera, Glossinidae) and Glossina palpalis gambiensis Vanderplank 1949. Legs were the most targeted parts of the body for tsetse-fly blood meals: 81% (95% CI: 73, 89) for G. tachinoides and 88% (81, 95) for G. palpalis.

The in-stable efficacy of footbath treatments was compared with manual full spraying with a 0.005% alphacypermethrin (Dominex, FMC, Philadelphia, USA) formulation (250 mL versus 2 L). The proportions of knocked-down flies were the same with footbath and full spray but the latter was more protective against fly bites. In field use, the efficacy of both methods should be similar given the recommended treatment frequency: 3 days for footbath versus 7 days for full spray.

Among 96 cattle drinking at the same water point in Dafinso (Burkina Faso), 68 (71%) were treated with a footbath containing a 0.005% deltamethrin formulation (Vectocid, CEVA SA, Libourne, France). We observed the effect of this live-bait technique on the one hand on released cohorts of reared, irradiated flies, and on the other hand on wild tsetse flies. In both cases, the footbath treatment was associated with a reduction of the apparent fly density probably related to an increased mortality.     

Mutated sodium channel genes and elevated monooxygenases are found in pyrethroid resistant populations of Sri Lankan malaria vectors

The present status of pyrethroid resistance in vectors of malaria; Anopheles culicifacies and Anopheles subpictus, was tested in two malarious Districts, Anuradhapura and Trincomalee, of Sri Lanka. Both species were resistant to permethrin and susceptible to cypermethrin and cyfluthrin. An. subpictus were resistant to deltamethrin. λ-Cyhalothrin and etofenprox resistance was shown only by Anuradhapura An. subpictus. Although there were no differences among the populations for esterase and glutathione S-transferase activities, increased monooxygenase levels were found among Trincomalee populations. The voltage-gated sodium channel gene, the target site gene of pyrethroids, was partially sequenced to screen for mutations previously associated with insecticide resistance. The classic leucine to phenylalanine substitution, TTA to TTT, was detected in An. subpictus. It appears that both kdr type and monooxygenase resistance underlie pyrethroid resistance in these two malaria vectors of Sri Lanka.     

Toxicity of Insecticides and Skin Care Products of Botanical Origin

Abstract— Toxicoses associated with products which are derived from plants and then used as insecticides and skin care/grooming aids on animals, are reviewed. These include pyrethrins, pyrethroids, rotenone, pennyroyal oil, d -limonene, linalool and melaleuca oil. Poisoning is uncommon and generally results from exposure to concentrations stronger than that recommended by the manufacturer. Pyrethrins and pyrethroids may cause excessive salivation, tremors, ataxia, depression, hyperexcitability/hyperactivity, seizures, dyspnea and rarely death of the animal. Ingestion of rotenone by licking may induce vomiting in dogs and cats. d -Limonene may cause excess salivation, marked hypothermia, shivering and ataxia in cats, and dermal exposure of cats to a spray containing linalool, d -limonene and piperonyl butoxide at 5 and 10 times normal concentration has caused depression and recumbency lasting for several DAys. This was followed by recovery without treatment. Melaleuca oil has been associated with ataxia, incoordination, weakness, tremors and depression. Bathing with a mild detergent, treatment of associated signs, and providing supportive care are usually adequate therapy for these toxicoses. An exception is pennyroyal oil which is hepatotoxic. Résumé— Les toxicités des produits d'origine végétale utilisés comme insecticides et comme topiques dermatologiques chez l'animal sont présentées. Ces produits comprennent les pyréthrines, les pyrethinoïdes, la roténone, l'huile de poulior, la citronnelle, le linalcool, et l'huile de melaleuca. Les intoxications sont rares et résultent généralement de l'exposition à des concentrations supérieures à celles recommandées par le fabricant. Les pyréthrines et les pyrethrinoïdes peuvent entraïner une siallhorée, des tremblements, une ataxie, un abattement, une hyperexcitabilité/hyperréactivité, des convulsions, une dyspnée, et rarement la siallhorée, une hypothermie marquée, des tremblements, et une ataxie chez le chat, et la pulvérisation de chats avec un aérosol contenant du linalool, de la citronnelle et du butoxyde de piperonyl à des concentrations 5 à 10 fois supérieures à la normale à provoqué un abattement et une prostration qui a duré plusieurs jours. Ceci a été suivi par une guérison sans traitement. L'huile de melalcuca a provoqué parfois ataxie, incoordination, faiblesse, tremelements et abattement. Les traitements indiqués lors d'intoxication associent un lavage avec un détergent doux, un traitement symptomatique et une réanimation. L'huile de poulior est une exception car elle est hépatotoxique. [Nicholson, S. S. Toxicity of insecticides and skin care products of botanical origin (Toxicité des insecticides et des produits dermatologiques d'origine végétale). Resumen— Se revisan las toxicosis asociadas a compuestos derivados de plantas y utilizados como insecticidas y productos dermatológicos o de cuidado de la piel en animales. En éstos se incluyen piretrinas, piretroides, rotenona, aceite de Mentha pulegium, D-limoneno, linanol y aceite de maleleuca. Las intoxicaciones son infrecuentes y son a menudo debidas uso de concentraciones mayores a las recomendadas por el productor. Las piretrinas y los piretroides pueden causar hipersialia, temblores, ataxia, depresión, hiperexcitabilidad, hiperactividad, ataques, dispnea y ocasionalmente muerte del animal. La ingestión de rotenona por lamido puede inducir el vómito en perros y gatos. El D-limoneno puede causar exceso de salivación, fuerte hipotermia, temblores y ataxia en gatos; la exposición de la piel del gato a un pulverizador con linalol, D-limoneno y butóxido de piperonilo a concentraciones 5 o 10 veces superior a la normal provocó depresión y postración de varios dias de duración. La recuperación a este cuadro fue completa sin tratamiento. El aceite de malaleuca se ha asociado con ataxia, incoordinación, debilidad, temblores y depresión. El traitamiento de estas toxicosis consiste en bañar al animal con un detergente suave, un tratamiento sintomático y teriapia de soporte. Una excepción a ésto es el aceite de Mentha pulegium, que es hepatotóxico. [Nicholson, S. S. Toxicity of insecticides and skin care products of botanical origin (Toxicidad de los insecticidas y productos dermatológicos de origen botánico).     

Frequencies of the M918I mutation in the sodium channel of the diamondback moth in China, Thailand and Japan and its association with pyrethroid resistance

In addition to the allele frequencies of the L1014F and T929I mutations which are involved in nerve-insensitive resistance to a pyrethroid, those of the M918I mutation were examined using field strains obtained in China, Thailand, and Japan during 2009-2011. Results show that the resistance allele frequencies at the L1014F site were 89-100%, 97-100% and 65-85%, respectively, for strains in China, Thailand, and Japan. The respective allele frequencies at the T929I site were 86-100%, 70-97% and 58-84% for Chinese, Thai, and Japanese strains. With low frequencies up to 27%, M918I was found in Japan and China, but not in Thailand. The strain homozygous for the M918I and L1014F mutations was established and its resistance level to a pyrethroid was examined. The strain lacks a portion of the sodium channel gene corresponding to the 3′ portion of exon 18a, intron 18, and the 5′ portion of exon 18b. Nevertheless, the strain showed a similar level of resistance to that which was homozygous for the T929I and L1014F mutations.     

3种拟除虫菊酯类杀虫剂对小白菜幼苗叶绿素和类胡萝卜素含量的影响

[目的]探究拟除虫菊酯类杀虫剂对小白菜叶绿素含量的影响。[方法]在人工气候培养箱中培育小白菜幼苗,至三叶一心时,用微量注射器分别用10μl不同浓度的氟氯氰菊酯、氯氟氰菊酯、溴氰菊酯处理第3片叶片,24 h后测定小白菜幼苗叶绿素和类胡萝卜素的含量。[结果]氯氟氰菊酯和稀释500、1 000倍的溴氰菊酯导致小白菜幼苗叶绿素a、叶绿素b、叶绿素总量、类胡萝卜素含量、叶绿素a/b值上升;氟氯氰菊酯和稀释1 500倍的溴氰菊酯则导致小白菜幼苗叶绿素a、叶绿素b、叶绿素总量、类胡萝卜素含量下降,叶绿素a/b值上升。[结论]氯氟氰菊酯和高浓度的溴氰菊酯处理对小白菜生长有促进作用,氟氯氰菊酯和低浓度的溴氰菊酯处理对小白菜生长有胁迫作用。     

取代苯甲醛肟羧酸酯的合成及生物活性研究(IV)——拟除虫菊酸4-二甲(乙)氨基苯甲醛肟酯的合成及生物活性

设计合成了 1 2个新拟除虫菊酸肟酯类化合物 ,并对其进行了生物活性测试 ,其中化合物 3e、3f对玉米螟致死活性最好 ,LC5 0 分别达 6.6～ 6.9mg/ L和 7.7～ 8.4mg/ L;化合物 3j对苹果轮纹病菌抑制率突出 ,50 mg/ L抑制率达 1 0 0 % ,1 mg/ L抑制率 50 %以上     

Assessment of the effects of crop injury by blackcurrant leaf midge,Dasineura tetensi (Rübsaamen) (Cecidomyiidae) on yield and growth in commercial blackcurrant plantations

Sex pheromone trap catches, galling damage, yield and growth were recorded over up to three successive seasons (2010–2012) in large replicated plots treated versus untreated with synthetic pyrethroid (SP) insecticides for blackcurrant leaf midge Dasineura tetensi control in eight established commercial blackcurrant plantations in southern England. The aim was to determine whether or not the current practice of spraying insecticides against the pest in commercial fruiting plantations is justified. In two separate small plot replicated experiments (in 2010 and 2011, respectively) in plantations which had been cut down in the previous winter, galling damage and shoot growth were recorded in the vigorous regrowth in plots treated versus untreated with SP insecticides against 1st, 2nd or both D. tetensi generations. Cutting down bushes to ground level in this way is a common way of regenerating plantations.In the experiments in the established fruiting plantations, applying sprays of insecticides led to substantial reductions in numbers of adult D. tetensi caught in sex pheromone traps (by 72% on average) and reductions in galling damage (by 75% on average) but did not result in increases in yield or statistically significant increases in shoot growth. Multiple possible mechanisms of yield compensation are discussed. In the experiments in the cut-down bushes where the galling was intense, the D. tetensi damage resulted in severe (59%) stunting and multiple branching of the regrowth which was weak and thin. Sprays against the 2nd generation only partially reduced stunting (to 24%).The results of this work call into question the current commercial practice of controlling this pest in established commercial plantations with sprays of insecticides: as significant increases in yield or growth did not result in these experiments, the effects of the sprays was largely cosmetic. Further, broad spectrum synthetic pyrethroid insecticides are likely to have persistent adverse effects on the natural enemies of D. tetensi. However, the work showed that control in re-growing cut-down plantations, and by analogy in young establishing plantations, is vital, as well as the value of the D. tetensi sex pheromone traps for timing sprays of insecticides.     

不同浓度菊酯类农药对黄河鲤鱼的急性毒性试验和MDA活性的影响

以黄河鲤鱼为试验动物,进行不同浓度水平的菊酯类农药对黄河鲤鱼的急性毒性试验和肝胰脏MDA活性的影响研究,结果表明:黄河鲤鱼对菊酯类农药比较敏感,其96 h的LC50为0.327μg/L,其安全质量浓度为0.0327μg/L。菊酯类农药对黄河鲤鱼肝胰脏影响较大,给药12和24 h后,给药组MDA含量高于对照组,给药12 h后0.02μg/L组与对照组差异显著(P<0.05),给药12和24 h后0.03μg/L组与对照组差异极显著(P<0.01);给药36 h后,给药组MDA含量显著低于对照组(P<0.05),说明:给药24 h之前黄河鲤鱼肝胰脏MDA活性最高。     

Insect spiracle as the main penetration route of pyrethroids

The penetration route of adhered pyrethroids following direct aerosol spraying was studied in the German cockroach (Blattella germanica) by investigating the relationship between the application site of insecticide and knockdown efficacy. In direct spray, KT₅₀ was 26.4 s and the adhered amount of pyrethroid was 0.745 μg. On the contrary, required amount of pyrethroid to obtain the same KT₅₀ was one-eighth in topical application to the mesothoracic spiracle, while 2.6 times to the ventral mesothorax. KT₅₀ of cockroaches with blocked mesothoracic spiracles was greater than those with unblocked spiracles by 1.8-fold. The amount of directly sprayed pyrethroid penetrating through the inner wall of the mesothoracic trachea was significantly higher than the amount penetrating through the body wall of the ventral mesothorax. Therefore, the knockdown effect of the direct spray was believed to be caused by the flow of pyrethroids into the mesothoracic spiracles and its subsequent penetration through the inner wall of the mesothoracic trachea.