Impact of Climate Change on Voltinism and Prospective Diapause Induction of a Global Pest Insect – Cydia pomonella (L.)

Global warming will lead to earlier beginnings and prolongation of growing seasons in temperate regions and will have pronounced effects on phenology and life-history adaptation in many species. These changes were not easy to simulate for actual phenologies because of the rudimentary temporal (season) and spatial (regional) resolution of climate model projections. We investigate the effect of climate change on the regional incidence of a pest insect with nearly worldwide distribution and very high potential for adaptation to season length and temperature – the Codling Moth, Cydia pomonella. Seasonal and regional climate change signals were downscaled to the hourly temporal scale of a pest phenology model and the spatial scale of pest habitats using a stochastic weather generator operating at daily scale in combination with a re-sampling approach for simulation of hourly weather data. Under future conditions of increased temperatures (2045–2074), the present risk of below 20% for a pronounced second generation (peak larval emergence) in Switzerland will increase to 70–100%. The risk of an additional third generation will increase from presently 0–2% to 100%. We identified a significant two-week shift to earlier dates in phenological stages, such as overwintering adult flight. The relative extent (magnitude) of first generation pupae and all later stages will significantly increase. The presence of first generation pupae and later stages will be prolonged. A significant decrease in the length of overlap of first and second generation larval emergence was identified. Such shifts in phenology may induce changes in life-history traits regulating the life cycle. An accordingly life-history adaptation in photoperiodic diapause induction to shorter day-length is expected and would thereby even more increase the risk of an additional generation. With respect to Codling Moth management, the shifts in phenology and voltinism projected here will require adaptations of plant protection strategies to maintain their sustainability

Resource quality determines the evolution of resistance and its genetic basis

This is the final version. Available on open access from Wiley via the DOI in this recordData Availability: All the experimental data to support the findings of this study including all virus assay and development data is available at DataDryad. https://doi.org/10.5061/dryad.k98sf7m4g. The complete sequencing data in CRAM format is available from the European Bioinformatics Institute (EBI), under accession number PRJEB27964.Parasites impose strong selection on their hosts, but the level of any evolved resistance may be constrained by the availability of resources. However, studies identifying the genomic basis of such resource‐mediated selection are rare, particularly in non‐model organisms. Here, we investigated the role of nutrition in the evolution of resistance to a DNA virus (PiGV), and any associated trade‐offs in a lepidopteran pest species (Plodia interpunctella). Through selection experiments and whole genome re‐sequencing we identify genetic markers of resistance that vary between the nutritional environments during selection. We do not find consistent evolution of resistance in the presence of virus but rather see substantial variation among replicate populations. Resistance in a low nutrition environment is negatively correlated with growth rate, consistent with an established trade‐off between immunity and development, but this relationship is highly context dependent. Whole genome resequencing of the host shows that resistance mechanisms are likely to be highly polygenic and although the underlying genetic architecture may differ between high and low nutrition environments, similar mechanisms are commonly used. As a whole, our results emphasise the importance of the resource environment on influencing the evolution of resistance.Natural Environment Research Council (NERC)National Institutes of Health (NIH

A chromosome-level genome assembly of Cydia pomonella provides insights into chemical ecology and insecticide resistance

The codling moth Cydia pomonella, a major invasive pest of pome fruit, has spread around the globe in the last half century. We generated a chromosome-level scaffold assembly including the Z chromosome and a portion of the W chromosome. This assembly reveals the duplication of an olfactory receptor gene (OR3), which we demonstrate enhances the ability of C. pomonella to exploit kairomones and pheromones in locating both host plants and mates. Genome-wide association studies contrasting insecticide-resistant and susceptible strains identify hundreds of single nucleotide polymorphisms (SNPs) potentially associated with insecticide resistance, including three SNPs found in the promoter of CYP6B2. RNAi knockdown of CYP6B2 increases C. pomonella sensitivity to two insecticides, deltamethrin and azinphos methyl. The high-quality genome assembly of C. pomonella informs the genetic basis of its invasiveness, suggesting the codling moth has distinctive capabilities and adaptive potential that may explain its worldwide expansion

Regulatory Framework for Plant Protection in Organic Farming

Plant protection in organic farming has to simultaneously comply with two sets of regulations: regulations on organic production and pesticide legislation. This chapter describes the organic approach to plant protection, including the role of systems management versus direct interventions, the range of authorised substances and the procedures for authorising new substances and the withdrawal of old substances. External factors not related to organic farming also influence the availability of plant protection products. Scientific, regulatory and economic aspects may limit the registration of substances in a given country. On the other hand, there is an alternative route for the registration of fertilisers and plant strengtheners in some countries. As a result, the range of plant protection products available to organic farmers varies from one country to another. The history of the authorisation of sodium bicarbonate, spinosad, copper fungicides, clay minerals and granulosis viruses illustrates how the two sets of regulations can interact in very different ways, creating different patterns of availability. The practice of plant protection is illustrated for the prevention and control of apple scab, fire blight and codling moth in organic apple orchards. At the end of the chapter, research perspectives for a ‘self-regulating’ apple orchard where plant protection fully relies on systems management are presented. The level of environmental friendliness already achieved by organic plant protection is discussed, and approaches with the potential for improvement are identified

Rapid Emergence of Baculovirus Resistance in Codling Moth to Dominant, Sex-linked Inheritance

Insect-specific baculoviruses are increasingly used as biocontrol agents of lepidopteran pests in agriculture and forestry, and thy have been previously regarded as robust to resistance development by the insects. However, in more than a dozen cases of field resistance of codling moth Cydia pomonella to commercially applied C. pomonella granulovirus (CpGV) in German orchards, resistance ratios exceed 1000. The rapid emergence of resistance is facilitated by sex-linkage and concentration dependant dominance of the major resistance gene and genetic uniformity of the virus. When the gene is fixed, resistance levels approach 100.000-fold. Our findings highlight the need for development of resistance management strategies for baculoviruses. (C)2007, American Association for the Advancement of Scienc

Pyrethroid resistance and its inheritance in a field population of Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae)

Citation: Rodrigues, A. R. S., Ruberson, J. R., Torres, J. B., Siqueira, H. A. A., & Scott, J. G. (2013). Pyrethroid resistance and its inheritance in a field population of Hippodamia convergens (Guérin-Méneville) (Coleoptera: Coccinellidae). Retrieved from http://krex.ksu.eduThe convergent lady beetle (CLB), Hippodamia convergens (Guérin-Méneville), a species widely distributed and used in biological control, has exhibited high survival under field and laboratory conditions when treated with field rates of the pyrethroid λ-cyhalothrin, a highly unusual phenomenon for a natural enemy. This work investigated and characterized the phenomenon of pyrethroid resistance in a population of this species collected in Georgia, USA. The mechanism and level of resistance were evaluated by treating parental populations with λ-cyhalothrin ± piperonyl butoxide (PBO). The inheritance bioassay utilized parental crosses and backcrosses between parental populations to obtain testable progenies. Adult beetles from populations and progenies were topically treated with different doses of λ-cyhalothrin (technical grade) to calculate knockdown (KD) and lethal (LD) doses, and to investigate the dominance based on a single dose and whether resistance is autosomal and monogenic (null hypothesis). Genetic variation in the parental populations was examined by applying a discriminating dose for resistant individuals (0.5 g/L). The data indicate that resistance is due to at least two factors: knockdown resistance and enzymatic detoxification of the insecticide. The knockdown effect is recessive and linked to the X-chromosome. Variability in proportions of individuals within families dying following knockdown indicated genetic variation in the resistant population. Further studies should be done to investigate the role of sex linked inheritance of resistance in the species and interactions of the various mechanisms involved in resistance

Deletion of a gene encoding an amino acid transporter in the midgut membrane causes resistance to a Bombyx parvo-like virus

Bombyx mori densovirus type 2 (BmDNV-2), a parvo-like virus, replicates only in midgut columnar cells and causes fatal disease. The resistance expressed in some silkworm strains against the virus is determined by a single gene, nsd-2, which is characterized as nonsusceptibility irrespective of the viral dose. However, the responsible gene has been unknown. We isolated the nsd-2 gene by positional cloning. The virus resistance is caused by a 6-kb deletion in the ORF of a gene encoding a 12-pass transmembrane protein, a member of an amino acid transporter family, and expressed only in midgut. Germ-line transformation with a wild-type transgene expressed in the midgut restores susceptibility, showing that the defective membrane protein is responsible for resistance. Cumulatively, our data show that the membrane protein is a functional receptor for BmDNV-2. This is a previously undescribed report of positional cloning of a mutant gene in Bombyx and isolation of an absolute virus resistance gene in insects