Argyresthia Conjugella Research Articles

Novel insight into lepidopteran phylogenetics from the mitochondrial genome of the apple fruit moth of the family Argyresthiidae

BackgroundThe order Lepidoptera has an abundance of species, including both agriculturally beneficial and detrimental insects. Molecular data has been used to investigate the phylogenetic relationships of major subdivisions in Lepidoptera, which has enhanced our understanding of the evolutionary relationships at the family and superfamily levels. However, the phylogenetic placement of many superfamilies and/or families in this order is still unknown. In this study, we determine the systematic status of the family Argyresthiidae within Lepidoptera and explore its phylogenetic affinities and implications for the evolution of the order. We describe the first mitochondrial (mt) genome from a member of Argyresthiidae, the apple fruit moth Argyresthia conjugella. The insect is an important pest on apples in Fennoscandia, as it switches hosts when the main host fails to produce crops.ResultsThe mt genome of A. conjugella contains 16,044 bp and encodes all 37 genes commonly found in insect mt genomes, including 13 protein-coding genes (PCGs), two ribosomal RNAs, 22 transfer RNAs, and a large control region (1101 bp). The nucleotide composition was extremely AT-rich (82%). All detected PCGs (13) began with an ATN codon and terminated with a TAA stop codon, except the start codon in cox1 is ATT. All 22 tRNAs had cloverleaf secondary structures, except trnS1, where one of the dihydrouridine (DHU) arms is missing, reflecting potential differences in gene expression. When compared to the mt genomes of 507 other Lepidoptera representing 18 superfamilies and 42 families, phylogenomic analyses found that A. conjugella had the closest relationship with the Plutellidae family (Yponomeutoidea-super family). We also detected a sister relationship between Yponomeutoidea and the superfamily Tineidae.ConclusionsOur results underline the potential importance of mt genomes in comparative genomic analyses of Lepidoptera species and provide valuable evolutionary insight across the tree of Lepidoptera species.

Pesticide use, arthropod fauna and fruit damage in apple orchards in a Nordic climate Pesticides and arthropods in Nordic apple orchards.

Integrated pest management (IPM) has a long history in fruit production and has become even more important with the implementation of the EU directive 2009/128/EC making IPM mandatory. In this study, we surveyed 30 apple orchards in Norway for three years (2016-2018) monitoring pest- and beneficial arthropods as well as evaluating fruit damage. We obtained growers' diaries of pest management and used these data to study positive and negative correlations of pesticides with the different arthropod groups and damage due to pests. IPM level had no significant effects on damage of harvested apples by arthropod pests. Furthermore, damage by arthropods was mainly caused by lepidopteran larvae, tortricids being especially important. The number of insecticide applications varied between 0 and 3 per year (mean 0.8), while acaricide applications varied between 0 and 1 per year (mean 0.06). Applications were often based on forecasts of important pest species such as the apple fruit moth (Argyresthia conjugella). Narrow-spectrum insecticides were commonly used against aphids and lepidopteran larvae, although broad-spectrum neonicotinoid (thiacloprid) insecticides were also applied. Anthocorid bugs and phytoseiid mites were the most abundant natural enemies in the studied orchards. However, we found large differences in abundance of various "beneficials" (e.g. lacewings, anthocorids, parasitic wasps) between eastern and western Norway. A low level of IPM negatively affected the abundance of spiders. Lepidoptera was found to be the most important pest group in apple orchards. Insecticide use was overall low, but number of spray applications and use of broad-spectrum insecticides varied between growers and regions. IPM level did not predict the level of fruit damage by insects nor the abundance of important pests or most beneficial groups in an apple orchard. This article is protected by copyright. All rights reserved.

Risk Assessment of the Pesticide Coragen 20 SC with the Active Substance Chlorantraniliprole

Coragen 20 SC is a new product in Norway containing the active substance chlorantraniliprole. It is applied for use in apples against codling moth (Cydia pomonella), apple fruit moth (Argyresthia conjugella) and free leaf living larvae. The Norwegian Scientific Committee for Food Safety (VKM) was asked by the Norwegian Food Safety Authority to perform a risk assessment on human health, environmental fate and ecotoxicological of the active substance and the product. The risk assessment of the product was approved at a meeting 11th of May 2010 by VKMs Scientific Panel on Pesticides (Panel 2). VKMs Panel 2 concludes as following: The product and the active substance have low acute oral, dermal and inhalation toxicities. Both are non-irritating to the skin, and no allergenic potential by skin contact were shown. Coragen was non-irritating to the eyes, while chlorantraniliprole showed a weak irritating potential. Chlorantraniliprole is not shown to have any genotoxic or carcinogenic potential, or to be teratogenic or toxic to the reproduction of female animals. The potential for testicular toxicity of chlorantraniliprole is unclear because the study design and the limited number of young dogs (2/sex/group) do not provide basis for a firm conclusion. No particular target organ for toxicity in any species in the sub-chronic and chronic toxicity studies was seen. The observed dose- and time dependent increased degree of microvesiculation in the zona fasiculata of the adrenal cortex in male rats, is however of uncertain biological significance. All test species (rat, mice, dog) showed physiological adaption to chlorantraniliprole administration (increased liver metabolism with induction of cytochrome P450 enzymes) which was manifested as increased liver weight and hepatocellular hypertrophy. In the chronic toxicity study in mice, the increased liver weight and hepatocellular hypertophy was accompanied with eosinofilic foci, which was assessed as an adverse effect. The no observed effect level (NOAEL) derived from this study serves as basis for calculations of values for acceptable daily intake (ADI) and acceptable operator exposure level (AOEL). 
 In Panel 2‘s opinion a sub-chronic study (90 days) with the technical material (E2Y45-282) including relevant concentration of the impurity IN-G2S78 should be performed. This would bring information on possible influence of the impurity on the toxicological profile of the technical material, and consequently on the assessment of the NOAELs in the various toxic studies. 
 The estimated risk for operator and for bystanders or for workers re-entering treated crops is assessed as minimal. 
 Chlorantraniliprole is persistent in soil with half live of about 1 year. The long half life indicates high potential for accumulation in soil after repeated use, which is confirmed by both model simulations and field studies. The Panel considers field data from the south of Europe not to be relevant for the Nordic conditions based on different climate conditions and soil properties contributing in different directions.
 The Panel considers that the existing documentation is not sufficient for a firm conclusion on the use of normalised field data for modelling purposes. However, the substance is persistent and expected to accumulate in soil. The Panel concludes that there is minimal risk for toxic effects on mammals, birds, bees, and microorganisms in soil due to chlorantraniliprole exposure with the proposed exposure regime. Panel concludes that there is “very high risk” for effects on in-field non target arthropods from chlorantraniliprole exposure. 
 For soil living invertebrates, earthworms seem rather insensitive to chlorantraniliprole and the Panel considers the toxic effects to be minimal. Panel considers the risk for toxic effects on soil living arthropods to be high. Crustaceans and insects larvae are the aquatic organisms most sensitive to chlorantraniliprole. The Panel concludes that there is a minimal risk of toxic effects on aquatic organisms due to exposure to chlorantraniliprole with the proposed application regime provided that a buffer zone of 30 m to surface water is applied.

Large-scale genetic admixture suggests high dispersal in an insect pest, the apple fruit moth.

Knowledge about population genetic structure and dispersal capabilities is important for the development of targeted management strategies for agricultural pest species. The apple fruit moth, Argyresthia conjugella (Lepidoptera, Yponomeutidae), is a pre-dispersal seed predator. Larvae feed on rowanberries (Sorbus aucuparia), and when rowanberry seed production is low (i.e., inter-masting), the moth switches from laying eggs in rowanberries to apples (Malus domestica), resulting in devastating losses in apple crops. Using genetic methods, we investigated if this small moth expresses any local genetic structure, or alternatively if gene flow may be high within the Scandinavian Peninsula (~850.000 km2, 55o - 69o N). Genetic diversity was found to be high (n = 669, mean He = 0.71). For three out of ten tetranucleotide STRs, we detected heterozygote deficiency caused by null alleles, but tests showed little impact on the overall results. Genetic differentiation between the 28 sampling locations was very low (average FST = 0.016, P < 0.000). Surprisingly, we found that all individuals could be assigned to one of two non-geographic genetic clusters, and that a third, geographic cluster was found to be associated with 30% of the sampling locations, with weak but significant signals of isolation-by-distance. Conclusively, our findings suggest wind-aided dispersal and spatial synchrony of both sexes of the apple fruit moth over large areas and across very different climatic zones. We speculate that the species may recently have had two separate genetic origins caused by a genetic bottleneck after inter-masting, followed by rapid dispersal and homogenization of the gene pool across the landscape. We suggest further investigations of spatial genetic similarities and differences of the apple fruit moth at larger geographical scales, through life-stages, across inter-masting, and during attacks by the parasitoid wasp (Microgaster politus).

THE COMPLEX OF ARTHROPOD-PESTS OF THE GENUS SORBUS L. PLANTS

The article represents research findings as for the species composition identification of the arthropod-pests of the genus Sorbus. The study was conducted in the period from April to October during several years in greenery on the territory of Kyiv and the Kyiv region. Four groups of pests were distinguished: pests of root system (6 species), pests of leaves (18 species), pests of fruits (2 species), pests of sprouts (4 species). Twenty-nine species of arthropods of the hexapods (Insecta) which belong to the 6 numbers of plant groups and 1 species of acariform mites (Acariformes, Arachnida) were found and identified. The most numerous species were arthropod pests, the representatives of the order Coleoptera – 10 species – and Lepidoptera – 8 species. The greatest damage caused by pests at different stages of their biological development was inflicted on the leaf cover of rowan – 60%, and its root system – 20%. Significant damage to rowan plants was caused by pests – polyphagous: Gryllotalpa gryllotalpa L., Psylla mali Schm., Aphis pomi De Green, Rhopalosiphum insertum Wal., Edwardsiana rosae L., Lepidosaphes ulmi L., Operophtera brumata L., Мelolontha melolontha L., Selatosomus aeneus L., Scolytus mali Bech., Phyllobius argentatus L., Agrotis segetum Den.et Schiff., Yponomeuta melinellus L., Simaethis pariana L., Argyresthia conjugella Zell., Pentatrichopus sp. The thorough analysis of damage to various parts of plants was carried out. In most instances, the greatest damage by pests to plants was observed on densely clustered plantations of rowan compared to single and small groups of trees and the presence of plants of the family Rosaceae as an additional forage base. The physiological condition of plants was significantly worsened by the adverse impacts of critical environmental factors. The damage to rowan by pests had a clear mosaic character and depended on various biotic and abiotic environmental factors.

Monitoring of the Apple Fruit Moth: Detection of Genetic Variation and Structure Applying a Novel Multiplex Set of 19 STR Markers.

The apple fruit moth Argyresthia conjugella (Lepidoptera, Yponomeutidae) is a seed predator of rowan (Sorbus aucuparia) and is distributed in Europe and Asia. In Fennoscandia (Finland, Norway and Sweden), rowan fruit production is low every 2–4 years, and apple (Malus domestica) functions as an alternative host, resulting in economic loss in apple crops in inter-mast years. We have used Illumina MiSeq sequencing to identify a set of 19 novel tetra-nucleotide short tandem repeats (STRs) in Argyresthia conjugella. Such motifs are recommended for genetic monitoring, which may help to determine the eco-evolutionary processes acting on this pest insect. The 19 STRs were optimized and amplified into five multiplex PCR reactions. We tested individuals collected from Norway and Sweden (n = 64), and detected very high genetic variation (average 13.6 alleles, He = 0.75) compared to most other Lepidoptera species studied so far. Spatial genetic differentiation was low and gene flow was high in the test populations, although two non-spatial clusters could be detected. We conclude that this set of genetic markers may be a useful resource for population genetic monitoring of this economical important insect species.

The Ratio between Field Attractive and Background Volatiles Encodes Host-Plant Recognition in a Specialist Moth.

Volatiles emitted by plants convey an array of information through different trophic levels. Animals such as host-seeking herbivores encounter plumes with filaments from both host and non-host plants. While studies showed a behavioral effect of non-host plants on herbivore host location, less information is available on how a searching insect herbivore perceives and flies upwind to a host-plant odor plume within a background of non-host volatiles. We hypothesized here that herbivorous insects in search of a host-plant can discriminate plumes of host and non-host plants and that the taxonomic relatedness of the non-host have an effect on finding the host. We also predicted that the ratio between certain plant volatiles is cognized as host-plant recognition cue by a receiver herbivorous insect. To verify these hypotheses we measured the wind tunnel response of the moth Argyresthia conjugella to the host plant rowan, to non-host plants taxonomically related (Rosaceae, apple and pear) or unrelated to the host (Pinaceae, spruce) and to binary combination of host and non-host plants. Volatiles were collected from all plant combinations and delivered to the test insect via an ultrasonic sprayer as an artificial plume. While the response to the rowan as a plant was not affected by the addition of any of the non-host plants, the attraction to the corresponding sprayed headspace decreased when pear or apple but not spruce were added to rowan. A similar result was measured toward the odor exiting a jar where freshly cut plant material of apple or pear or spruce was intermixed with rowan. Dose-response gas-chromatography coupled to electroantennography revealed the presence of seven field attractive and seven background non-attractive antennally active compounds. Although the abundance of field attractive and of some background volatiles decreased in all dual combinations in comparison with rowan alone, an increased amount of the background compounds (3E)-4,8-Dimethyl-1,3,7-nonatriene ((E)-DMNT) and (Z)-3-hexenyl acetate was found in the rowan-apple and rowan-pear but not in the rowan-spruce headspace. A higher ratio between the abundance of each field attractive component and that of (E)-DMNT and (Z)-3-hexenyl acetate was measured for rowan and rowan-spruce in contrast to rowan-pear and rowan-apple headspaces. Our result suggests that the ratio between field attractive and background antennaly active volatiles encodes host-plant recognition in our study system.

Genetic Diversity in Apple Fruit Moth Indicate Different Clusters in the Two Most Important Apple Growing Regions of Norway

The apple fruit moth (Argyresthia conjugella (A. conjugella)) in Norway was first identified as a pest in apple production in 1899. We here report the first genetic analysis of A. conjugella using molecular markers. Amplified fragment length polymorphism (AFLP) analysis was applied to 95 individuals from six different locations in the two most important apple-growing regions of Norway. Five AFLP primer combinations gave 410 clear polymorphic bands that distinguished all the individuals. Further genetic analysis using the Dice coefficient, Principal Coordinate analysis (PCO) and Bayesian analyses suggested clustering of the individuals into two main groups showing substantial genetic distance. Analysis of molecular variance (AMOVA) revealed greater variation among populations (77.94%) than within populations (22.06%) and significant and high FST values were determined between the two major regions (Distance = 230 km, FST = 0.780). AFLP analysis revealed low to moderate genetic diversity in our population sample from Norway (Average: 0.31 expected heterozygosity). The positive significant correlation between the geographic and the molecular data (r2 = 0.6700) indicate that genetic differences between the two major regions may be due to geographical barriers such as high mountain plateaus (Hardangervidda) in addition to isolation by distance (IBD).

Spotting the invaders: A monitoring system based on plant volatiles to forecast apple fruit moth attacks in apple orchards

The exploitation of cues mediating insect–plant interactions with a view to enhance sustainable management of agro-ecosystems is an exciting and emergent area. Practical applications are, however, limited due to discrepancies between attraction of insects to lures in the laboratory and in the field. We hypothesised that the background odour of the crop along with the modality of release of volatiles in the field could play a role in filling the gap. Our study system comprised the apple fruit moth Argyresthia conjugella, its native host, rowan, Sorbus aucuparia, and the recurrently colonised secondary host apple, Malus communis. The attractiveness of several sources, including host plants, their collected headspaces and synthetic mimics, was measured both in the laboratory and in the field. In orchards, apple fruit moth females and males were caught in traps baited with rowan clusters. In the wind tunnel, attraction was observed when rowan (either as plant or headspace) was used as stimulus. The background from apple did not affect the attraction to the rowan odour. Whilst the response to a two-component rowan mimic decreased in the presence of an apple background, a seven-component mimic remained effective in such a background. In rowan intermast years, traps baited with this blend caught consistent numbers of moths during their migration to apple. Long lasting dispensing devices with a controlled release over the entire period of pest migration allowed a much more consistent catch of moths compared to a standard device. Results indicate that knowledge of the volatile background of the crop and of the optimisation of the dispensing device is essential when moving attractants from the laboratory or semi-laboratory environment out into the field. By considering these factors, we developed a plant volatile-based attractant to monitor the apple fruit moth and use insecticides only where and when needed. Our concept can be extended to other insect–plant interactions.

Discrepancy in laboratory and field attraction of apple fruit moth Argyresthia conjugella to host plant volatiles

Abstract Apple fruit moth Argyresthia conjugella is a specialist seed predator of rowan Sorbus aucuparia. Large‐scale synchronous fluctuation of seed production in rowan (i.e. named masting) drives the apple fruit moth to seek alternative host plants such as apple, during years when rowan berries are not available for oviposition. The role of plant volatile compounds in the attraction of gravid apple fruit moth females is studied in a laboratory wind tunnel. Volatiles from rowan branches with green berries stimulate female moths to fly upwind and to land at the odour source. By contrast, females are not attracted to rowan branches without green berries, and they are not attracted to apple, demonstrating that the chemical stimulus from rowan berries is required for attraction. Attraction to synthetic compounds identified from rowan, anethole and 2‐phenyl ethanol confirms the role of plant volatiles in host finding. These two compounds, however, show a discrepant behavioural effect in wind tunnel and field tests. Field traps baited with 2‐phenyl ethanol capture female moths but anethole does not produce significant captures. Wind tunnel tests produce the opposite results: moths fly upwind towards the anethole lure, whereas 2‐phenyl ethanol is not attractive at all. Wind tunnel attraction to 2‐phenyl ethanol is achieved by adding odour from a rowan branch without berries, which is not attractive on its own. This finding demonstrates that interaction with the background odour contributes to the behavioural effect of plant volatile stimuli in the field.

Plant volatiles mediate attraction to host and non‐host plant in apple fruit moth, Argyresthia conjugella

AbstractPlant volatiles mediate host finding in insect herbivores and lead to host fidelity and habitat‐specific mating, generating premating reproductive isolation and facilitating sympatric divergence. The apple fruit moth, Argyresthia conjugella Zeller (Lepidoptera: Argyresthiidae), is a particularly suitable species to study the cues and behavioural mechanisms leading to colonization of a new host: it recurrently oviposits on the non‐host plant, apple Malus domestica Borkh. (Rosaceae), where the larvae cannot complete their development. The larval host of the apple fruit moth (Lepidoptera, Argyresthiidae), is rowan Sorbus aucuparia L. (Rosaceae). Fruit setting in rowan, however, fluctuates strongly over large areas in Scandinavia. Every 2–4 years, when too few rowanberries are available for egg laying in forests, apple fruit moth females oviposit instead on apple in nearby orchards, but not on other fruits, such as pear or plum. This poses the question of which cues mediate attraction to rowan and apple, and how apple fruit moth discriminates rowan from apple. Chemical analysis and antennal recordings showed that 11 out of 15 rowan volatiles eliciting an antennal response in A. conjugella females co‐occur in rowan and apple headspace, in a different proportion. In the field, A. conjugella was attracted to several of these plant volatiles, especially to 2‐phenyl ethanol, methyl salicylate, and decanal. Addition of anethole to 2‐phenyl ethanol had a strong synergistic effect, the 1 : 1 blend is a powerful attractant for A. conjugella males and females. These results confirm that volatiles common to both plants may account for a host switch in A. conjugella from rowan to apple. Some of the most attractive compounds, including 2‐phenyl ethanol, anethole, and decanal, which have been found in several apple cultivars, were not present in the headspace of the apple cultivar, Aroma, which is also susceptible to attack by A. conjugella. This supports the idea that the odour signal from apple is suboptimal for attraction of A. conjugella, but is nonetheless sufficient for attraction, during times when rowan is not available for egg laying.

When does the apple fruit moth (Argyresthia conjugella) fly and oviposit?

When does the apple fruit moth (<i>Argyresthia conjugella</i>) fly and oviposit?

Masting and trophic cascades: interplay between rowan trees, apple fruit moth, and their parasitoid in southern Norway

We analyzed berry production in rowan, Sorbus aucuparia L., in southern Norway and examined the ramifying effects of rowan masting on the dynamics of the dominant seed predator and its parasitoid. The apple fruit moth, Argyresthia conjugella Zeller, is a pre‐dispersal seed predator of rowan. The larva of the apple fruit moth rely on rowan berries, which in turn is attacked by the parasitoid wasp, Microgaster politus Marsh. We found classic masting in rowan: berry production varied across years (the mean coefficient of variation=1.02) and was spatially synchronized at large scale (the averaged correlation coefficient=0.67). Berry production represented a two‐year cycle in western but a three‐year cycle in eastern Norway. The abundance of the moth and the parasitoid also varied across years and were spatially synchronized. The degree of spatial synchrony decreased and cyclicity became obscure with increasing trophic level. We attempted to assess two different components to the predator satiation, functional and numerical satiations, based on a simple population dynamics model. The observed pattern of seed predation testified that both of functional and numerical satiations were at work in this system. In a comparison at different locations, rowan trees with more variable berry production were more effective in reducing losses to the seed predator. The parasitoids also seemed to experience satiation through the fluctuation in their host abundance. These results show that rowan masting has an adaptive foundation, which impacts the dynamics of higher trophic levels.

Masting of rowan Sorbus aucuparia L. and consequences for the apple fruit moth Argyresthia conjugella Zeller

AbstractMasting of rowan Sorbus aucuparia L. has been studied in 45 sites in southern Norway for 22 years. We present data on the year‐to‐year variation in fruit setting of rowan, and show that masting is spatially synchronous in Norway and probably all over Fennoscandia. The apple fruit moth Argyresthia conjugella Zeller is an important seed predator on rowan. We present data on the abundance of apple fruit moth in rowanberries during these years and discuss the consequences of masting and intermasting of rowan for apple fruit moth as a pest of apple. We conclude that growth and climate have little impact on flowering intensity and suggest that masting of rowan is an adaptive defense against seed predation and a new example of predator satiation: intermast years inhibit predators and prepare the rowan for the subsequent mast.

Spatial and temporal distribution of bioclimatic potential for the Codling moth and the Colorado potato beetle in Norway: model predictions versus climate and field data from the 1990s

Abstract 1 Based on climate data from a network of agrometeorological stations in Norway, the effects of current and future climate regimes on the spatial and temporal distribution of the Codling moth (Cydia pomonella) and the establishment potential of the Colorado potato beetle (Leptinotarsa decemlineata) were investigated.2 The study was accomplished using climex, a dynamic climate matching‐ and climate response estimation model, which predicts potential distribution of an organism based on its known geographical distribution.3 Validation of the climex model predictions for C. pomonella against field data on spatial distribution of the species in Norway resulted in a refined set of climate response parameters for C. pomonella. Temporal occurrence of C. pomonella seems to be affected by climate (temperature) and insecticide treatment against the Apple fruit moth (Argyresthia conjugella) in the previous season.4 Climate change scenarios (0.1 °C increase per degree in latitude in daily maximum and minimum temperatures) indicated an extension of the potential geographical range for C. pomonella, and 23 new locations were found favourable for its long‐term survival. The abundance and pest status of C. pomonella could increase dramatically in those locations where the species is already established.5 Leptinotarsa decemlineata would only temporarily find suitable climate conditions in Norway and hence only be able to establish interim populations in a few regions under current climate conditions. Climate change scenarios for L. decemlineata indicated that the species would be able to establish as far north as 64°N, mainly in the inland of eastern Norway.6 In general, the methods applied support the process of decreasing the uncertainty both in our knowledge about the pests themselves and about the environment, which are crucial elements in predicting whether a species is able to establish in a new area.

Sex pheromone of apple fruit moth Argyresthia conjugella (Lepidoptera: Argyresthiidae)

Abstract The apple fruit moth Argyresthia conjugella Zell. (Lepidoptera: Argyresthiidae) is the most important pest of apple in Scandinavia. It invades apple orchards and can destroy an entire crop during years of poor flowering and fruitsetting of its principal host, mountain ash Sorbus aucuparia. We investigated the female sex pheromone of apple fruit moth in order to develop a reliable lure, which can be used to detect migration of apple fruit moth into orchards and thus to avoid preventive insecticide sprays. Pheromonal compounds obtained by solvent extraction of excised A. conjugella female pheromone glands were identified by coupled gas chromatography/electroantennography and gas chromatography/mass spectrometry. Two compounds (Z)‐11‐hexadecenyl acetate, and the analogous alcohol (Z)‐11‐hexadecen‐1‐ol, elicited a strong response from male antennae. (Z)‐11‐hexadecenyl acetate was highly attractive in field trapping tests, whereas as little as a 1%‐addition of (Z)‐11‐hexadecen‐1‐ol strongly reduced male attraction. (Z)‐13‐octadecenyl acetate, a previously reported sex attractant, had no effect on A. conjugella male attraction.

Occurrence of apple fruit moth(Argyresthia conjugellazeller) in Lahaul Valley of Himachal Pradesh, India

Occurrence of apple fruit moth<i>(Argyresthia conjugella</i>zeller) in Lahaul Valley of Himachal Pradesh, India

Studies on the apple fruit moth,Argyresthia conjugellaZeller (Yponomeutidae: Lepidoptera): Identification, distribution and extent of damage in India

Abstract A fruit‐damaging insect on apple in the Kinnaur district of Himachal Pradesh has been identified as the apple fruit moth/miner, Argyresthia conjugella Zeller, a common pest of apple in Asian, European and American countries. It seems to be native to India, where its primary host, the sorb tree, Sorbus aucuparis Linn. is present. Studies on the distribution and extent of damage during 1983 and 1984 revealed that the pest was distributed in the Kinnaur district at altitude between 2445 to 2900 m and in yearly isotherms of 0 to 10° C. The damage varied from zero to above 50%. Its spread to other apple growing areas of the state is unlikely due to unsuitable agroclimatic conditions.

A SERIOUS ATTACK ON THE APPLE FRUIT BY ARGYRESTHIA CONJUGELLA (Zell.) IN EUROPE

In the annual reports of the Canadian Experimental Farms for 1896 and 1897, Dr. James Fletcher describes a new apple-fruit pest in British Columbia, caused by the attacks of small caterpillars, viz., the larvæ of a little tineid moth, Argyresthia conjugella, Zell. The injuries done by this new enemy, called by Mr. Fletcher “the applefruit miner,” closely resemble those caused by the apple maggot, Trypeta pomonella, Walsh. The caterpillars tunnel the pulp of the fruit in every direction, leaving brown-coloured channels with rather large chambers here and there; this attack thus being easily distinguishable from that of the common codling worm.