Effects of cycloxaprid,a novel cis‐nitromethylene neonicotinoid insecticide,on the feeding behaviour of Sitobion avenae

BACKGROUND: Cycloxaprid with cis‐configuration is a novel neonicotinoid insecticide, developed in China, that has good industrialisation prospects for its high activity against imidacloprid‐resistant pests. Studies were carried out to investigate the biological activity of cycloxaprid and its effect on the feeding behaviour of Sitobion avenae. RESULTS: The results demonstrated that cycloxaprid had good contact and root‐systemic activity. The electrical penetration graph (EPG) revealed that cycloxaprid significantly increased the total time of non‐probing periods and greatly inhibited phloem ingestion of treated aphids because it significantly reduced the total time and the frequency of phloem ingestion. Furthermore, cycloxaprid can increase the phloem salivation of treated aphids by comparison with aphids treated with imdacloprid and distilled water. Consequently, a sublethal dose of cycloxaprid impaired aphid ingestion of phloem sap and thereby reduced the weight of aphids. On the other hand, EPG data showed that a sublethal dose of cycloxaprid had no significant effect on xylem sap ingestion, in contrast to imidacloprid. CONCLUSION: All these tests indicated that cycloxaprid had both contact and root‐systemic activity, with sublethal effects resulting in reduction in Sitobion avenae phloem‐feeding behaviour and growth rate. Copyright © 2012 Society of Chemical Industry     

吡蚜酮对禾谷缢管蚜的亚致死效应

本文研究了吡蚜酮对禾谷缢管蚜的亚致死效应。试验利用刺探电位图谱(EPG)技术测定了亚致死剂量的吡蚜酮对禾谷缢管蚜成虫取食行为的影响,结果表明:经吡蚜酮处理的蚜虫口针从开始刺探到持续吸食韧皮部和木质部汁液的时间明显延长,分别延长至(199.9±34.0)min和(236.4±29.5)min,对照分别为(155.5±18.1)min和(145.5±27.1)min。并且,经药剂处理的蚜虫口针在韧皮部和木质部中持续取食的时间明显缩短,分别为(44.7±9.4)min和(11.8±2.5)min,对照分别为(93.0±24.9)min和(19.0±3.6)min。通过生长和繁殖试验可知:亚致死剂量的吡蚜酮使禾谷缢管蚜的重量显著减轻,繁殖率明显降低。经药剂处理的蚜虫最大重量和最高繁殖率分别为(1.28±0.025)mg/10头和(2.9±0.2)头/成蚜,而对照分别为(1.56±0.099)mg/10头,(5.2±0.2)头/成蚜。     

Electrical penetration graph evidence that pymetrozine toxicity to the rice brown planthopper is by inhibition of phloem feeding

BACKGROUND: Pymetrozine is a valuable novel insecticide for control of sucking insects, including the brown planthopper Nilaparvata lugens (Stål), one of the most serious pests on rice. This study was conducted to elucidate the action mechanisms of pymetrozine on the feeding behaviour of the planthopper. RESULTS: The activity test showed that pymetrozine primarily functioned as an antifeedant that caused starvation and death in N. lugens, rather than having neurotoxicity. Pymetrozine‐treated insects died at a significantly slower speed than insects treated with starvation. Electrical penetration graph (EPG) data indicated that pymetrozine significantly increased the duration of non‐probing periods and had a strong inhibition to phloem ingestion. The inhibition was strongly dose dependent, resulting in a complete suppression of the activity in the phloem region when the pymetrozine concentration was increased to 400 mg L^?1. Starvation caused by inhibition of phloem ingestion might be a major toxicity mechanism of pymetrozine. EPG data also showed that pymetrozine had no significant effect on stylet movement and duration of xylem sap ingestion. CONCLUSION: The study revealed that pymetrozine disturbed the feeding behaviour of N. lugens mainly by increasing the non‐probe period and inhibiting phloem ingestion. The inhibition resulted in a slow death similar to starvation. Copyright © 2011 Society of Chemical Industry     

Translocation of Pymetrozine in Plants

Pymetrozine, a pyridine-azomethine, is a selective biocide against aphids, whiteflies and plant hoppers with a high plant systemic activity. By means of bioassays and autoradiographic techniques it has been shown that this systemic behaviour originates not only from xylem but also from phloem mobility. After foliar application the growing points of plants are protected by pymetrozine imports mainly from leaves. This indicates a high importance of phloem mobility for the systemic activity of pymetrozine against plant-sucking insects. © 1997 SCI.     

Pymetrozine,a Fast-Acting and Selective Inhibitor of Aphid Feeding. In-situ Studies with Electronic Monitoring of Feeding Behaviour

Pymetrozine, a pyridine azomethine compound, represents a novel insecticide with a selective activity against homopteran insects. It acts in a unique way: aphids are not knocked down on contact but seem to die of starvation. This implies an effect of pymetrozine on feeding behaviour. The aim of the present work was to elucidate how and at which step pymetrozine interferes with the complex mechanisms underlying phloem feeding. The effect of pymetrozine, applied in various ways, on different phases of stylet penetration and feeding activity of individual aphids was studied using the Electrical Penetration Graph technique (EPG). Initial choice experiments indicated that pymetrozine does not have a deterrent or antifeedant action. Topical application (150 ng pymetrozine mg^-1 fresh weight) inhibited stylet insertion into the plant. When injected, less than 30 ng mg^-1 was sufficient to produce the same effect. When pymetrozine was systemically applied via plant spraying or root uptake, aphids started feeding normally. After some time, however, they withdrew their stylets from the phloem and walked around with unaffected locomotion. At low doses aphids eventually recovered and resumed feeding. High doses, however, irreversibly disrupted feeding and prevented stylet reinsertion. Aphid motility was not affected up to an estimated haemolymph concentration of 1 mM pymetrozine. Aphids which eventually stopped feeding on pymetrozine-treated plants showed EPGs with distorted salivation/ingestion patterns. It is concluded that pymetrozine does not have a general toxic effect on aphids but selectively interferes with the nervous regulation of feeding behaviour which consequently results in death due to starvation after a few days. © 1997 SCI.     

Divergent effects of PVY-infected potato plant on aphids

Host plant selection by aphids can be positively or negatively affected when plants are infected by phytoviruses. Potato plants infected by Potato virus Y (PVY), a non-persistent virus, are reported to affect settling behaviour and growth parameters of Myzus persicae Sulzer and Macrosiphum euphorbiae Thomas. Using the Electrical penetration graph system (EPG), we demonstrated that PVY-infection of potato plants influences the feeding behaviour of these two aphid species. Myzus persicae exhibited increased phloem sap ingestion and reduced non-probing duration. Macrosiphum euphorbiae showed delayed stylet insertion, reduced activity in the phloem vessels and an enhanced non-probing duration. In addition, we showed that these two species exhibited different transmission rates. The opposite effects of PVY-infected potato plant on these two aphids are discussed in terms of PVY spreading in the field.     

柑橘三种蚜虫取食行为的EPG分析

为探究柑橘3种蚜虫取食行为差异,利用刺吸电位图谱(electrical penetration graph,EPG)技术对褐色橘蚜Toxoptera citricida(Kirkaldy)、棉蚜Aphis gossypii Glover和绣线橘蚜Aphis citricola van der Goot在椪柑上的取食行为进行了测定。结果表明:3种蚜虫均产生8种取食波形,依次为非刺探波(np波)、路径波(A、B、C波)、电位下降波(pd波)、韧皮部分泌唾液波(El波)、韧皮部被动吸食波(E2波)以及木质部主动吸食波(G波)。棉蚜开始取食的第1次刺探时间最早,绣线橘蚜刺探的次数最多,且C波时间最长。褐色橘蚜pd波出现的次数最少,棉蚜次之,绣线橘蚜最多,显著高于褐色橘蚜。与其它2种蚜虫相比,绣线橘蚜于木质部主动吸食汁液(G波)时间最长,有G波的个体比例最高。3种蚜虫E1波次数和总持续时间差异均不显著,但褐色橘蚜E2波的持续时间217.01±27.56 min显著长于棉蚜142.49±27.85 min和绣线橘蚜116.64±20.05 min。初步推断3种蚜虫对柑橘衰退病毒的传毒效率与E2波有关。     

亚致死浓度毒死蜱对小麦禾谷缢管蚜生长和繁殖的影响

为探讨毒死蜱对小麦禾谷缢管蚜Rhopalosiphum padi(Linnaeus)的亚致死效应,采用玻璃管药膜法确定了其亚致死浓度(LC10、LC20和LC30),并研究了该浓度下毒死蜱对小麦禾谷缢管蚜生长和繁殖的影响。结果表明:以LC10、LC20和LC30浓度处理后,禾谷缢管蚜成蚜的寿命分别为(8.60±0.22)、(8.03±0.18)和(6.68±0.18)d,均显著短于对照的(10.36±0.31)d;单雌产仔量分别为(21.88±0.63)、(20.41±0.53)和(16.68±0.35)只,也均显著少于对照的(26.40±0.89)只;产仔历期分别为(7.55±0.22)、(6.69±0.17)和(5.64±0.15)d,均显著短于对照的(9.13±0.31)d;试验浓度药剂处理对下一代若蚜期的影响不显著;LC30浓度处理对下一代成蚜繁殖有显著的抑制作用,可减少单雌产仔量3.74只,缩短产仔历期1.39 d。生命表参数分析表明:LC30浓度毒死蜱处理使小麦禾谷缢管蚜的净增殖率(R0)比对照降低了34.71%,使种群加倍时间(t)比对照延长了17.37%;LC20浓度处理使小麦禾谷缢管蚜的平均世代历期(T)延长了12.59%;LC10浓度处理组各项指标与对照间无显著性差异。研究表明,亚致死浓度毒死蜱能够缩短小麦禾谷缢管蚜成蚜的寿命,降低其繁殖力,该结果对小麦禾谷缢管蚜综合防治策略的制定具有积极意义。     

麦蚜对吡虫啉的敏感性及吡虫啉有效用量的评价

室内测定结果表明 ,禾谷缢管蚜对吡虫啉的敏感性比麦长管蚜高 ,其LC₅₀之比为1∶3左右。田间试验结果明确 ,吡虫啉持效性好 ,其持效期与吡虫啉用量和麦蚜种类有关。小麦穗蚜发生始盛期是吡虫啉防治麦蚜的最佳时期 ,防治禾谷缢管蚜最佳有效用药量为1g/667m²,麦长管蚜为2g/667m²。     

基于EPG分析无翅型和有翅型柑橘蚜虫的取食行为

为明确无翅型、有翅型柑橘蚜虫取食行为的差异,采用EPG技术对褐色橘蚜Toxoptera citricida(Kirkaldy)和棉蚜Aphis gossypii Glover的有翅型、无翅型成蚜在柑橘苗上的取食行为进行测定。结果表明,褐色橘蚜无翅型和有翅型的EPG均记录到7种取食波形,依次为非刺探波np、路径波A、B和C、电位下降波pd、韧皮部取食波E1和E2;棉蚜无翅型和有翅型的EPG记录到9种取食波形,除上述7种外,还包括木质部主动吸食波G和口针阻碍波F。褐色橘蚜有翅型和无翅型的np波持续时间为25.73 min和8.39 min,二者间差异显著;棉蚜有翅型的np波持续时间、刺探次数、C波次数分别为27.34 min、19.16次、20.21次,显著高于无翅型,而刺探总持续时间为332.66 min,显著低于无翅型。棉蚜的C波次数及总持续时间、刺探次数、pd波次数及总持续时间均显著高于褐色橘蚜,而E2波总持续时间及平均持续时间均显著小于褐色橘蚜。表明棉蚜无翅型比有翅型在柑橘上更容易取食,影响有翅型蚜虫取食的抗性因子可能位于柑橘表面;褐色橘蚜比棉蚜对柑橘的适应性更强。     

Virulence of Verticillium lecanii (Z.) against cereal aphids; does timing of infection affect the performance of parasitoids and predators?

BACKGROUND: Entomopathogenic fungi such as Verticillium lecanii (Z.) (Mycotal^®) are used for pest control as an alternative to chemical control. In this study, the effect of V. lecanii on cereal aphids is assessed. In addition, an investigation is carried out to determine whether the use of V. lecanii affects the performance of two natural enemies of aphids, the predator Harmonia axyridis (P.) and the parasitoid Aphidius colemani (V.), in no‐choice experiments under laboratory conditions. RESULTS: The number of Rhopalosiphum padi (L.) and Sitobion avenae (F.) killed was increased by increasing the concentration of V. lecanii. The timing of application of fungus to aphids affected the efficacy of other biocontrol agents, a parasitoid and a predator. Parasitation by A. colemani (V.) in both cereal aphids (S. avenae and R. padi) was not affected by V. lecanii when aphids were first treated with V. lecanii and then exposed to A. colemani. The emergence of adults from parasitised mummies was, however, lower in infected aphids than in uninfected aphids when the aphids were first exposed to the parasitoids and then treated with fungus. The female sex ratio in the emerging adults was lower in V. lecanii‐treated aphids in both species. When aphids were first treated with V. lecanii, 72 h before predation, fewer aphids of both species were consumed by H. axyridis (P.). CONCLUSION: Use of entomopathogenic fungus as a biological control agent could be a complementary strategy in an integrated pest management programme against cereal aphids, but it can reduce the efficiency of other biocontrol agents (parasitoids and predators) when applied simultaneously. © 2012 Society of Chemical Industry     

Flonicamid, a novel insecticide with a rapid inhibitory effect on aphid feeding

Flonicamid (IKI220; N-cyanomethyl-4-trifluoromethylnicotinamide), a pyridinecarboxamide compound, is a novel systemic insecticide with selective activity against hemipterous pests, such as aphids and whiteflies, and thysanopterous pests. The purpose of this study is to clarify the biological properties of flonicamid against aphids. Flonicamid is very active against aphids, regardless of differences in species, stages and morphs. This compound inhibited the feeding behaviour of aphids within 0.5 h of treatment without noticeable poisoning symptoms such as convulsion, and this antifeeding activity was not recoverable until death. The nymphs born from adults exposed to flonicamid for 3 h showed high mortality. The effect of flonicamid on the feeding activity of an individual aphid was studied using electronic monitoring of insect feeding behaviour (EMIF). Although the treated aphid attached the head of its proboscis to the leaf surface, salivation and sap feeding were strongly inhibited. These results suggest that the main insecticidal mechanism of flonicamid is starvation based on the inhibition of stylet penetration to plant tissues.     

Sublethal effect of Beauveria bassiana on feeding and fecundity of the sunn pest,Eurygaster integriceps Puton (Hemiptera: Scutelleridae)

The sunn pest, Eurygaster integriceps Puton, is a major pest of wheat in West and Central Asia. Studies were conducted to investigate the effect of Beauveria bassiana (teleomorph; Cordyceps bassiana) isolates on the sunn pest. Bioassays were done with adult insects collected from overwintering sites at three different times. The effect of sublethal doses of fungi on the insects’ feeding and fecundity was determined. When the sunn pest adults were treated with 2 × 10⁷ conidia mL^?1, all isolates caused significant sunn pest mortality varying between 24 and 100% 12 days after inoculation. There were significant differences between mortality, depending on the date of fungal application. Adult sunn pests treated with B. bassiana at sublethal concentrations caused significantly less damage to wheat leaves than sunn pests in the control. The number of eggs laid by the sunn pest was significantly fewer when wheat plots in plastic greenhouse and field cages were infested with adult sunn pests treated at sublethal concentrations, compared with sunn pests in control plots. Results show that sublethal dosages of B. bassiana reduced sunn pest feeding and fecundity. Applying B. bassiana in sunn pest overwintering sites minimizes the pest populations, which would move to wheat fields in spring.     

内共生菌Buchnera协助蚜虫抑制寄主植物的防御反应

为明确蚜虫内共生细菌Buchnera能否协助蚜虫抑制植物的防御反应,采用混合抗生素除去瓜蚜Aphis gossypii体内的Buchnera,采用刺吸电位技术和生命表方法比较除菌瓜蚜和正常瓜蚜在黄瓜上的适合度,并测定被除菌瓜蚜和正常瓜蚜预侵染黄瓜叶片中H₂O₂、茉莉酸和水杨酸的含量变化以及抗蚜特性变化。结果表明,除菌瓜蚜体重较正常瓜蚜极显著下降了71.15%,净增殖率极显著下降了95.60%,但寿命延长了2.34倍;刺吸电位图谱显示除菌瓜蚜几乎不产生代表唾液分泌的E1波和韧皮部被动吸食的E2波。在黄瓜叶片中,除菌瓜蚜比正常瓜蚜能激发产生更高水平的H₂O₂;在为期14 d的侵染中,除菌瓜蚜侵染诱发总茉莉酸含量持续升高、总水杨酸含量持续下降,而正常瓜蚜侵染诱发总茉莉酸含量先升高后降低、总水杨酸含量先降低后升高。在被除菌瓜蚜预侵染黄瓜上,瓜蚜进入稳定取食的时间显著滞后于正常瓜蚜预侵染处理,且前3 d的产蚜量显著低于正常瓜蚜预侵染处理。表明Buchnera除了可为蚜虫提供必需的营养外,还有调控和抑制寄主植物防御反应的功能。     

Activity of the botanical aphicides 1,5‐diphenyl‐1‐pentanone and 1,5‐diphenyl‐2‐penten‐1‐one on two species of Aphididnae

1,5‐Diphenyl‐1‐pentanone (A) and 1,5‐diphenyl‐2‐penten‐1‐one (B) are natural products extracted for the first time from Stellera chamaejasme. Laboratory bioassay showed that the two products have strong contact activity and very good anti‐feedant activity against Aphis gossypii and Schizaphis graminum. Both products showed dose‐dependent relationships for both forms of activity against the two aphids, the contact activity of B being about twice that of A. Both products were inferior to methomyl in contact activity but superior in anti‐feedant activity against the two aphids. This is the first report of aphicidal activity in these two compounds, which may represent a new class of aphicide. © 2001 Society of Chemical Industry     

Feeding behavior of<Emphasis Type="Italic">Aphis gossypii</Emphasis> on resistant accessions of different melon genotypes (<Emphasis Type="Italic">Cucumis melo</Emphasis>)

The feeding behavior of the melon aphidAphis gossypii Glover (Homoptera: Aphididae) was monitored using the electrical penetration graph (EPG) technique on different melon (Cucumis melo L.) genotypes showing resistance to the aphid. The aphid-resistant genotypes used were PI-161375 and PI-414723, sources of theVat andAgr genes, respectively. TGR-1551, a newC. melo accession from Zimbabwe, was also tested. Our goal was to localize the tissues where the resistance factors are expressed and to determine if the resistance mechanisms operating in the three aphid-resistant accessions were the same. Our results indicated that the three selected lines have resistant factors located at the epidermis, mesophyll and vascular tissues. However, the behavior ofA. gossypii on TGR-1551 was different from the two other resistant accessions, as indicated by a longer phloem salivation phase (E1 phase). Many of the E1 phases observed for aphids feeding on TGR-1551 were not followed by phloem ingestion (E2 phase). These results suggest that TGR-1551 has a resistance mechanism that preventsA. gossypii from initiating ingestion from the phloem. Preference tests under free choice conditions also showed that aphids rejected accessions TGR-1551 or PI-414723 faster than PI-161375. Our results support the hypothesis thatAgr andVat are coding for different kinds of resistance strategies. Comparisons of aphid life history parameters also indicated that TGR-1551 is a very promising new source to breed for resistance againstA. gossypii. http://www.phytoparasitica.org posting Jan. 16, 2002.     

Antifeedant and sublethal effects of imidacloprid on Asian citrus psyllid,Diaphorina citri

BACKGROUND: Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, transmits the causal bacteria of the devastating citrus disease huanglongbing (HLB). Because of the variation in spatial and temporal uptake and systemic distribution of imidacloprid applied to citrus trees and its degradation over time in citrus trees, ACP adults and nymphs are exposed to concentrations that may not cause immediate mortality but rather sublethal effects. The objective of this laboratory study was to determine the effects of sublethal concentrations of imidacloprid on ACP life stages. RESULTS: Feeding by ACP adults and nymphs on plants treated daily with a sublethal concentration (0.1 µg mL^?1) of imidacloprid significantly decreased adult longevity (8 days), fecundity (33%) and fertility (6%), as well as nymph survival (12%) and developmental rate compared with untreated controls. The magnitude of these negative effects was directly related to exposure duration and concentration. Furthermore, ACP adults that fed on citrus leaves treated systemically with lethal and sublethal concentrations of imidacloprid excreted significantly less honeydew (7–94%) compared with controls in a concentration‐dependent manner suggesting antifeedant activity of imidacloprid. CONCLUSIONS: Sublethal concentrations of imidacloprid negatively affect development, reproduction, survival and longevity of ACP, which likely contributes to population reductions over time. Also, reduced feeding by ACP adults on plants treated with sublethal concentrations of imidacloprid may potentially decrease the capacity of ACP to successfully acquire and transmit the HLB causal pathogen. Copyright © 2009 Society of Chemical Industry     

Investigation of a permethrin-induced antifeedant effect in Drosophila melanogaster: An ethological approach

A permethrin-induced antifeedant effect was demonstrated in Drosophila melanogaster topically treated with a dose of 1.25 ng per fly (LD₅₀ and LD₁₀ were 18.5 and 7.4 ng of permethrin per fly, respectively). The reduction in food consumption in treated flies was due to a decrease in the frequency of feeding and not to the duration of individual meals. These results suggested that the sublethal effect occurred before the process of ingestion. Furthermore, a time-sampling study of individual flies, 30 min after treatment, revealed that the relative frequency of the components of general behaviour were altered. Specifically, locomotory behaviour and inactivity were significantly decreased in contrast to preening, which increased. Continuous observation for 30 min revealed that whilst the length of preening bouts was unaltered, their frequency of occurrence was significantly increased in permethrin-treated flies. The length of bouts of locomotory activity was significantly reduced in treated individuals, but the frequency was increased. The length of rest periods was reduced in treated flies, but no influence of the insecticide could be detected on their bout frequency. Sequential analysis of the transition frequencies of the behavioural components suggested that an underlying disorganisation of general behaviour resulted from the insecticide treatment. Further analysis, of the behaviour of those flies that had fed, indicated that the probability of tasting leading to feeding was decreased by permethrin. The increase in preening behaviour was thought to cause the reduction in locomotor activity, that ultimately resulted in the reduction in feeding. This is discussed in relation to the physiological basis of pyrethroid action and a subsequent irritation response to low doses.     

O3浓度升高对棉蚜取食行为的影响

在加倍O3浓度的开顶式气室(OTC)中培养抗虫棉GK12幼苗30 d,正常O3浓度处理为对照。应用刺探电位图谱(EPG)技术,对棉蚜(Aphis gossypii Glover)在苗期棉花上的取食行为进行了比较研究。结果表明：蚜虫在加倍O3浓度下生长的棉苗上取食的过程中,C波数量显著减少,pd波首次出现时间明显提前,被动取食持续时间(E2波的总时间)明显拉长。棉蚜的取食适合度明显提高的原因可能是加倍O3浓度对棉花叶片组织结构和体内营养物质的变化有影响。     

Designer repellents: combining olfactory, visual or taste cues with a secondary repellent to deter free-ranging house sparrows from feeding

BACKGROUND: Repellents may prevent bird pests from eating crops or protect non‐target birds from eating harmful substances. The feeding behaviour of free‐ranging house sparrows (Passer domesticus) presented with wheat treated with the secondary repellent anthraquinone (AQ), paired with visual and/or olfactory and taste cues, was recorded in a series of trials. The aim was to determine the suitability of repellent combinations for preventing birds from consuming pest baits. RESULTS: Anthraquinone significantly reduced wheat consumption. The addition of cinnamon oil did not reduce consumption further, but the addition of either a blue colour or d‐pulegone enhanced repellency. Green wheat was consumed more than blue wheat. In a multichoice test, the sparrows did not differentiate between low and high concentrations of AQ on blue‐dyed wheat. With treatments on separate tables, the higher concentration was more repellent. Additional olfactory/gustatory cues palatable to pest mammals did not make the AQ‐treated wheat more or less acceptable to sparrows. AQ‐treated blue wheat with/without cinnamon oil was more repellent than green wheat with cinnamon oil, a colour/odour combination typically used for pest baits in New Zealand. CONCLUSIONS: These data demonstrate the potential of combining the secondary repellent AQ with additional salient cues for modifying the feeding behaviour of sparrows. Copyright © 2011 Society of Chemical Industry