Enzymatic diagnosis of resistance to deltamethrin in diapausing larvae of the codling moth,Cydia pomonella (L.)

The resistance to deltamethrin was evaluated in diapausing larvae of 14 field populations of the codling moth (Cydia pomonella L.) From the main French orchard areas using biological assays. Resistance to deltamethrin was compared to mixed-function-oxidase (mfo) activity measured at the individual level through ethoxycoumarin-O-deethylase (ECOD) activity using a fluorescence microplate reader. The larvae were collected in corrugated paper band traps in the autumn of 1995. Analysis was previously performed on two laboratory strains, one susceptible and one resistant to deltamethrin, in order to characterize the changes in resistance during diapause development. Resistance to deltamethrin as well as the ECOD activity were stable during the diapause, and ECOD activity was always significantly lower in the susceptible strain than in the resistant one. The ECOD activity was significantly correlated to the frequency of resistant moths in the field populations. This strongly suggested the involvement of the mfo system in the resistance to deltamethrin in these populations. The intra-strain variabilities in ECOD activity of both laboratory and field resistant insects indicated that other resistance mechanisms might also be involved. Further investigations on these mechanisms are needed in order to develop complete diagnostic methods and to define suitable control strategies against each resistant population. Arch. Insect Biochem. Physiol. 39:55–64, 1998. © 1998 Wiley-Liss, Inc.     

Age-dependent response to insecticides and enzymatic variation in susceptible and resistant codling moth larvae

Insecticide resistance in the codling moth, Cydia pomonella, partly results from increased metabolic detoxification. The aim of this study was to follow the age variations in larval susceptibility to deltamethrin and teflubenzuron in one susceptible (S) strain, and two resistant (Rv and Rt) ones selected for resistance to deltamethrin and diflubenzuron, respectively. The age variation of the activities of cytochrome P450-dependent monooxygenase (MFO), glutathione S-transferases (GST), and esterases in S and both resistant strains were simultaneously investigated. The highest levels of insecticide resistance were recorded in late instars in both resistant strains, although Rv neonates exhibited enhanced resistance to deltamethrin. The involvement of an additional deltamethrin-specific mechanism of resistance, which could be mainly expressed in early instars, was supported by previous demonstration of a kdr point mutation in the Rv strain. The cross-resistance between deltamethrin and teflubenzuron indicated the involvement of non-specific metabolic pathways in resistance to teflubenzuron, rather than target site modification. A positive correlation between enhanced GST activities and deltamethrin resistance suggested that this mechanism might take place into the adaptive response of C. pomonella to pyrethroids treatments. Enhanced MFO activity was recorded in each instar of the two resistant strains compared to the susceptible one. But these activities were not correlated to the responses to deltamethrin nor to teflubenzuron. In the light of these findings, studying age-dependence of responses to selection is central to the implementation of monitoring tests of resistances, especially if the target instars are difficult to collect in the field.     

Infectivity of a Bulgarian and an American strain ofSteinernema carpocapsae against codling moth

A strain of Steinernemacarpocapsae obtained from overwintering codling mothscollected in Bulgaria was identified to species usingthe polymerase chain reaction. The infectivity ofthis strain towards codling moth prepupae was comparedto that of a U.S. strain at three temperatures (11, 15and 20 °C). Infectivity was low at 11 °C with 8%mortality recorded for both strains. Mortality was61% and 62% at 15 °C, and 82% and 81% at 20 °C forthe Bulgarian and U.S. strain, respectively. The meanpercent mortality at each individual temperature wassignificantly different from each other whenmortalities of the two strains were combined. Thus,the Bulgarian strain did not provide a low temperatureinfectivity advantage compared to the U.S. strain.     

Local and regional climate variables driving spring phenology of tortricid pests: a 36 year study

1. Insect phenology is driven by local climate variables, most notably temperature. Increased warming has been linked to advancements in critical phenophases such as the spring flight of reproductive adults in the mid‐Atlantic region of the U.S.A. 2. Local climate is governed by the fluctuations of large‐scale climate oscillations. In the northern hemisphere, both the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) control the local autumn and winter severity. Low NAO and AO indices are associated with colder autumns and winters, which can delay spring phenology. 3. In this study, 36 years of data from experimental fruit orchards in Biglerville, Pennsylvania, were used to run partial least‐squares regressions in order to determine the climate variables related to the spring phenology of five tortricid pest species. 4. The phenology of the tortricid pests did not advance, even though there was evidence of warming at the research site. 5. Spring temperatures were found to be the most significant climate variables in determining the timing of the spring flights. However, autumn–winter temperatures were also important. 6. For the NAO and the AO, it was found that these oscillations affected the tortricid moths by influencing autumn–winter conditions. The oscillations of the NAO and AO can obscure long‐term changes in phenology. 7. These findings suggest that the inclusion of large‐scale climate oscillations can provide important insights into how climate conditions can influence insect phenology, and presents an opportunity for improving the ability to forecast spring emergence.     

甘肃苹果蠹蛾的发生现状与研究进展

苹果蠹蛾是果园最重要的害虫之一,1987年入侵甘肃敦煌,2005年苹果蠹蛾在河西地区严重发生。各地先后开展了一系列的防控与监测工作,并对苹果蠹蛾的发生规律及防治技术进行了大量的研究。本文就甘肃苹果蠹蛾的发生历史、为害与防控现状及其生物学、生态学及防治技术方面的研究进展进行概述,以期为全国苹果蠹蛾的防控提供参考。     

Five new species of Thripidae (Thysanoptera) endemic to New Zealand

Abstract

Three new species of genus Thrips are described—austellus, coprosmae, and phormiicola—which are closely related to the common New Zealand species T. obscuratus (Crawford). The systematic and zoogeographic significance of this endemic species-group is discussed. Physemothrips hadrus n.sp. is described from the South Island; the only other member of this genus is from Macquarie Island. Anaphothrips zelandicus n.sp. is described from the South Island and the Chatham and Antipodes islands, A. woodi Pitkin is recorded from New Zealand, and the relationships of these two species to the Australian fauna are discussed.     

A comparison of various mating disruption technologies for control of two internally feeding Lepidoptera in apples

Sex pheromone mating disruption (MD) is an approach used to control several moth pest species of pome fruit by disrupting the ability of the males to find females and consequently prevent mating. The following experiments were performed to determine the effectiveness of several new and experimental sex pheromone MD technologies, and dispenser densities for simultaneous control of the codling moth (CM), Cydia pomonella (L.), and the oriental fruit moth (OFM), Grapholita molesta (Busck) (both Lepidoptera: Tortricidae), in Pennsylvania apple orchards. In one study, three MD approaches to control CM and oriental fruit moth – CM and OFM Disrupt Micro‐Flakes, Isomate CM/OFM TT, and both a CideTrak OFM and a CideTrak CM dispenser containing both codlemone and pear ester – and an insecticides‐only treatment were compared over the course of 2 years. In the other studies, the efficacy of several CheckMate Duel dispenser densities (i.e., 250, 375, 425, and 500 dispensers ha^?1) were compared against Isomate CM/OFM TT, and an insecticides‐only treatment. The CideTrak CM/pear ester combination and Isomate CM/OFM TT treatments both substantially reduced CM captures in traps in 2007 and 2008. Meanwhile, OFM trap shutdown was highest in the CheckMate Duel densities of 375 (99.9 ± 0.08%) and 500 dispensers ha^?1 (98.9 ± 0.07%) and the Isomate CM/OFM TT treatment (98.0 ± 1.13%), and lowest in the 250 dispensers ha^?1 density treatment (94.3 ± 3.23%). In orchards where OFM is the dominant pest species, a CheckMate Duel dispenser density of 375 ha^?1 is necessary for effective control, whereas higher densities are needed to control CM.     

Potential for mating disruption to reduce cone damage by the spruce seed moth, Cydia strobilella, in spruce seed orchards

Abstract:  The spruce seed moth, Cydia strobilella (L.), is a serious and widely distributed pest of spruce seed orchards in North America and Europe. Current pest management activities in seed orchards rely mainly on chemical pesticides for insect control. Mating disruption with sex pheromone is a potential alternative pest management tool for C. strobilella . In 2002, field tests confirmed that sticky traps baited with 3  μ g of (E) -8-dodencenyl acetate ( E 8-12:Ac), the sex pheromone of C. strobilella , could capture males in Quebec, a region of Canada not previously monitored for this insect. In the following years (2003–2005), grey rubber septa loaded with 0.75, 1.5, or 2.0 mg of E 8-12:Ac were deployed separately in two white spruce seed orchards at a density of 40 and 60 dispensers/ha to test the potential for mating disruption. The results showed that the captures of male C. strobilella in the pheromone-treated plots were reduced by up to 98%. Furthermore, at the end of the experiment in 2005, 17.3% of cones were damaged by C. strobilella in the treated plot, compared with a significantly (P < 0.0001) higher 56.4% in the control plot. The results suggest that mating disruption has potential for controlling C. strobilella to protect seed cones in white spruce seed orchards.     

Genetic architecture in codling moth populations: comparison between microsatellite and insecticide resistance markers

The codling moth, Cydia pomonella, is renowned for developing resistance to insecticides and causing significant economic damage to pome fruits worldwide. In spite of its economic importance, little is known about the patterns of movement of this pest and the effects of insecticide treatment on the population genetic structure. Here, we investigated the genetic structure of the pest in 27 orchards from France, Italy, Armenia and Chile at seven microsatellite loci and two resistance markers [biochemical activity of cytochrome P450 oxidases and proportion of knockdown resistance (kdr) alleles in the sodium channel gene]. According to the microsatellite loci, we detected isolation by distance at the supranational scale but found no evidence of geographical structure among the 24 French orchards, which were mainly structured by the intensity of the insecticide treatments. Similarly, the highest levels of metabolic resistance associated with activity of the cytochrome P450 oxidases were detected in the most treated orchards. The kdr alleles were observed in southern France and Armenia where the pyrethroid insecticides were or have been intensively sprayed. The intensity of the insecticide treatments marginally affected the allelic richness in each orchard, but not the level of inbreeding. These results suggest important and high-distance gene flow among the codling moth populations, which were mainly structured according to the history of insecticide applications. Differences in mutation-migration-drift equilibrium among treated and untreated orchards also suggest that insecticide applications are the main force regulating the local dynamics of codling moth populations.