Systemic action of novel neonicotinoid insecticide IPP‐10 and its effect on the feeding behaviour of Rhopalosiphum padi on wheat

BACKGROUND: IPP‐10 is a novel neonicotinoid insecticide recently developed in China and has good activity against sucking insects. Studies were carried out to investigate the activity of IPP‐10 against Rhopalosiphum padi L. RESULTS: The results demonstrated that IPP‐10 had both contact and systemic activity, including acropetal and basipetal translocation in wheat vascular bundles. Starved R. padi were allowed to stay on wheat treated with a sublethal dose of IPP‐10. The results of studying their feeding behaviour from an electrical penetration graph (EPG) revealed a decrease in total time and bout duration of xylem and phloem ingestion, but the total time and bout duration of phloem salivation were significantly prolonged. The frequency (7.03 ± 0.49 Hz) of the xylem ingestion waveform produced by aphids on wheat treated with IPP‐10 was significantly lower than that of blank control aphids (8.20 ± 0.30 Hz). Consequently, aphids born on wheat treated with IPP‐10 were obviously lighter and less fecund than the control aphids. CONCLUSION: These tests indicated that IPP‐10 had both contact and systemic activity, with sublethal effects resulting in reduction in R. padi feeding behaviour, growth rate and fecundity. Copyright © 2010 Society of Chemical Industry     

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     

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.     

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.     

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。     

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。     

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     

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.     

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。     

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。     

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.     

Reduced BYDV–PAV transmission by the grain aphid in a <Emphasis Type="Italic">Triticum monococcum</Emphasis> line

The luteovirus Barley yellow dwarf virus–PAV (BYDV–PAV) and its vector, the aphid Sitobion avenae are two major sources of yield losses in cereal crops. We report in this paper the effects of a Triticum monococcum line (TM44), resistant by antibiosis to S. avenae, on the different steps of transmission of one BYDV–PAV isolate by the aphids. First, it was shown that TM44 is strongly resistant to BYDV–PAV transmission, but exclusively when S. avenae is the vector. Second, that TM44 is resistant (1) to BYDV–PAV acquisition by S. avenae and (2) to its inoculation, whatever the respective duration of these two periods. Third, that both resistances have partially additive effects. In the discussion, several lines of evidence are given to support the hypothesis that resistance of TM44 to PAV transmission is due to the same disturbances to S. avenae feeding behaviour that are involved in its antibiosis against this aphid species. Reasons for caution in releasing resistant material in the field are presented.     

CTV强弱毒株促进褐色橘蚜的取食

正由柑橘衰退病病毒(Citrus tristeza virus,CTV)引起的柑橘衰退病,对全世界柑橘产业造成了严重威胁。褐色橘蚜Toxoptera citricida(Kirkaldy)属半翅目蚜科,以非循回型半持久方式传播CTV,是CTV的最有效传播媒介~([1])。我国广泛分布着CTV的各种株系和传媒褐色橘蚜,对我     

小麦禾谷缢管蚜发生为害与生态环境研究

八十年代以来,我区麦蚜频繁成灾,减产2—3成的麦田较为普遍,研究证明:成灾的主要原因是优势种群已由麦长管蚜Sitobion avenae(Fabr.)转变为禾谷缢管蚜Rhopalosiphumpadi(L.)。田间调查弄清了禾谷缢管蚜在不同海拔高度的早、中、晚播麦田的不同生育阶段,以及在植株各部位的分布。穗期禾谷缢管蚜发生轻重与3月中旬平均温度呈正相关,与3月下旬雨量呈负相关。由此建立了预测禾谷缢管蚜发生程度的多元回归方程式: Y=0.792 0.205X_1-0.015X_2用这个预测式回测8年田间实测值与预测值极近。     

不同浓度吡虫啉对禾谷缢管蚜酯酶的影响

采用生物化学方法研究不同剂量吡虫啉对禾谷缢管蚜酯酶活性和酶动力学参数的影响.结果表明,不同浓度吡虫啉处理禾谷缢管蚜后,可极显著诱导禾谷缢管蚜蛋白含量增加和酯酶活力增强,且不同处理组间蛋白含量差异显著,但不同剂量吡虫啉处理并未对禾谷缢管蚜酯酶动力学参数产生明显影响.不同浓度吡虫啉处理禾谷缢管蚜后,并未改变其酯酶的性质,但酯酶的表达量显著增加.     

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     

Aphid feeding rates on healthy and beet curly top virus-infected plants

Based on the frequency of honeydew droplet excretion, the feeding rate of green peach aphids,Myzus persicae (Sulz.), on the swollen leaf veins of beet curly top virus-infectedAmsinckia douglasiana DC. plants was found to be almost twice as high as on the veins of uninfectedAmsinckia plants. Radiochemical analysis of the honeydew indicated that the phloem sap in the swollen veins has a higher sucrose concentration than that in uninfected plants. Although disease-associated changes in the anatomy and in the level of gustatory nutrients in the phloem sap may contribute to the enhanced feeding rate, a higher turgor pressure of the phloem sap in the swollen veins may be responsible for the higher feeding rate as well as for the occasional exudation of sap from such veins.     

Insecticidal action of phytohemagglutinin (PHA) against the grain aphid, Sitobion avenae

The effects of phytohemagglutinin (PHA) on development, fecundity, and mortality of the grain aphid, Sitobion avenae (Fabricius), were determined. Also determined were the effects of PHA on the activity of gut enzymes involved in sugar and phosphorus metabolism (α- and β-glucosidase and alkaline and acid phosphatase) and on the feeding behavior of adult apterae.When added to a liquid diet, PHA increased the pre-reproductive period, decreased fecundity, and increased mortality of S. avenae. PHA also increased the developmental time and reduced the intrinsic rate of natural increase. The aphids fed on sucrose-agarose gels with higher concentrations of PHA lectin exhibited no phloem-feeding behavior. The number of the gel penetrations was reduced and duration of the pathways was increased by higher concentrations of PHA. In addition, activities of α-glucosidase and alkaline phosphatase in homogenates of adult aphids were reduced. The results indicate that PHA has potential in a biotechnological approach to insect management.     

Biological characterization of sulfoxaflor, a novel insecticide

BACKGROUND: The commercialization of new insecticides is important for ensuring that multiple effective product choices are available. In particular, new insecticides that exhibit high potency and lack insecticidal cross‐resistance are particularly useful in insecticide resistance management (IRM) programs. Sulfoxaflor possesses these characteristics and is the first compound under development from the novel sulfoxamine class of insecticides. RESULTS: In the laboratory, sulfoxaflor demonstrated high levels of insecticidal potency against a broad range of sap‐feeding insect species. The potency of sulfoxaflor was comparable with that of commercial products, including neonicotinoids, for the control of a wide range of aphids, whiteflies (Homoptera) and true bugs (Heteroptera). Sulfoxaflor performed equally well in the laboratory against both insecticide‐susceptible and insecticide‐resistant populations of sweetpotato whitefly, Bemisia tabaci Gennadius, and brown planthopper, Nilaparvata lugens (Stål), including populations resistant to the neonicotinoid insecticide imidacloprid. These laboratory efficacy trends were confirmed in field trials from multiple geographies and crops, and in populations of insects with histories of repeated exposure to insecticides. In particular, a sulfoxaflor use rate of 25 g ha^?1 against cotton aphid (Aphis gossypii Glover) outperformed acetamiprid (25 g ha^?1) and dicrotophos (560 g ha^?1). Sulfoxaflor (50 g ha^?1) provided a control of sweetpotato whitefly equivalent to that of acetamiprid (75 g ha^?1) and imidacloprid (50 g ha^?1) and better than that of thiamethoxam (50 g ha^?1). CONCLUSION: The novel chemistry of sulfoxaflor, its unique biological spectrum of activity and its lack of cross‐resistance highlight the potential of sulfoxaflor as an important new tool for the control of sap‐feeding insect pests. Copyright © 2010 Society of Chemical Industry