The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. The relatively recent species divergence history is evident in mating compatibility between H. Despite periodic interceptions of H. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Historically H. The relatively recent species divergence history is evident in mating compatibility between H. Despite periodic interceptions of H. The economic, biosecurity, resistance management, ecological and evolutionary implications of this incursion are discussed in relation to the current agricultural practices in the Americas.
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.
Biological incursions can be natural e. Invasive species are not necessarily readily recognised especially when introduced into an environment where closely related species exist, and may displace other congeners  , . Rapid confirmation of such incursions is imperative and can be greatly assisted by characterisation of known genomic regions. Global trade is rapidly diminishing the effective distance between countries and border biosecurity via quarantine inspections represents the last line of defence.
Once breached, the establishment of invasive species can lead to rapid and significant negative economic and environmental impacts. Although restricted to the old world, H. Given the global nature of many prime host crops, the establishment of H. In Brazil H. In Australia there is considerable experience in managing the threat to agriculture posed by H.
However, from the outset high baseline levels of resistance were detected in this pest to one of the Bt toxins in current varieties and resistance risk remains a critical concern . Early detection of field-evolved resistance to Bt cotton was recently reported for H. Since the expansion of agriculture in the late 's in Brazil, a complex of insects and mites have established as pests that can contribute to significant yield losses. Noctuids Lepidoptera: Noctuidae are amongst the most destructive pest family.
Specifically, intensive cultivation of soybeans, corn and cotton, which for the past 20 years has characterized the Cerrado region Brazilian Savannah , is affected by an inter-crop pest complex composed of Chrysodeixis includens, Spodoptera frugiperda, S. Control of this pest complex is difficult due the broad range of hosts in the landscape including vast areas of non-monitored uncultivated plants which serve as refuges from chemical control, and sources for recolonisation.
Initially the species was presumed to be H. However, large numbers of row crops were attacked consecutively in the same agricultural landscape at unusually high infestations, and growers reported a reduced efficacy of different methods of control for the pest.
Consequently, investigations took place to determine if the species was indeed H. Recent reports suggest that H. Species identification based on morphological characters between H. Identification via male genitalia morphology has been used extensively however Pogue  reported overlapping ranges in male vesica between H. Well-characterised molecular markers  ,  can be used to confirm if this Old World pest has successfully established in the New World. This study reports for the first time at a molecular level that H.
We discuss the potential implications of incursions of H. We analysed 14 lepidopteran samples collected in from Mato Grosso in Brazil using two standard mtDNA markers that have been shown to effectively differentiate the four major Helicoverpa pest species including H.
The partial Cyt b region of the six H. The Brazilian H. A map of countries and locations of samples reported in this study is presented in Fig. A Cyt b haplotype network linking H.
The Cyt b haplotype network showed two nucleotide substitutions separating the Cyt b -Harm01 and Cyt b -Harm08 haplotypes where the current Brazilian H.
A total of 18 nucleotide substitutions separated the H. Figure 1 in  which suggested an African origin of present day H. Three populations of H. Sites where H. Individuals of H. A total of 26 H. Numbers of H. Numbers of nucleotide substitutions differentiating between haplotypes are indicated by black circles e. Genotyping of the six Brazilian H. Both H. Shifts in patterns of host use, levels of infestation, and efficacy of control methods against Helicoverpa spp.
In Mato Grosso, the occurrence of Helicoverpa spp. Soria unpublished data. The detection of H. The first entrance was presumably the result of natural spread possibly of African origins .
While the most recent invasion confirmed here is likely the result of human activity, there is nevertheless insufficient data to rule out chance natural spread events, since under favourable weather patterns H. Understanding the pathways to incursion by the Old World cotton bollworm is important and may assist in preventing potential incursions by other species such as the Solanaceae specialist Helicoverpa assulta from the Old World.
Our molecular analyses based on mtDNA markers suggest that the H. EPIC marker analyses of these six individuals confirmed that in addition to a separate maternal lineage as indicated by the mtDNA Cyt b -Harm08 haplotype, the remaining five individuals with the most prevalent mtDNA COI-Harm01 haplotype could be further explained by three separate maternal lineages Table S2.
This enables a conservative estimate of at least 4 separate matrilines in our six Brazilian H. Our estimates of matrilines in the limited Brazilian H. However, we have been unable to define the precise origins of the Brazilian H. The implications of a recent invasion of H.
Monitoring for pest resistance to insecticides and Bt varieties by researchers independent of technology providers has only recently begun in Brazil. There is no formal co-ordinated strategy for managing resistance to insecticide sprays. Since many populations of H. There would be strong selection on these individuals to enable them to rapidly exploit agricultural systems where the endemic pests remain susceptible to conventional pesticides.
In addition, the arrival of H. Currently these crops are grown without the mandated resistance management practices that are adopted elsewhere, including for example, the use of non-Bt refuge crops, and a mechanism to prevent carryover of potentially selected individuals from one crop to the next e. A further complication is that, despite the duration of speciation between H.
The close evolutionary relationship between these two species is further supported by H. However, hybridisation in the laboratory does not automatically mean that even if given the opportunity to co-exist in the field that hybrid offspring will result.
It is also possible that re-introduction of the original progenitor species, H. Genetic fitness in these hybrid offspring may present new challenges for IRM strategies.
Venette et al. Failure to develop effective control measures for potential arrival of H. An invasion of H. The incursion of H. Addressing these issues will be greatly benefited by knowledge of the H. Knowing how H. Permit access to collect material used in our research at various crop sites was granted by respective growers.
All suspect samples were analysed with no exclusion of any specimen even if believed to be H. A tissue fragment of each ethanol preserved specimen was cut off with sterilised scissors.
An extraction blank was simultaneously processed to ensure that there was no external source of H. The global H. We also included positive controls one Mato Grasso H. The fragment patterns were interpreted using Geneious Pro 5. Global Helicoverpa armigera and H. The authors greatly appreciate the support of growers who permit access to crops to collect material used in our research.
Expert technical assistance was provided by Bruno B. Batista and Danielle Souza. Degrande Federal University of Grande Dourados, Brazil helped improve clarity of a final version of this manuscript. Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field. Abstract The highly polyphagous Old World cotton bollworm Helicoverpa armigera is a quarantine agricultural pest for the American continents. Introduction Biological incursions can be natural e.
Results We analysed 14 lepidopteran samples collected in from Mato Grosso in Brazil using two standard mtDNA markers that have been shown to effectively differentiate the four major Helicoverpa pest species including H.
Download: PPT. Figure 1. A map of sampling sites and countries from which Helicoverpa armigera and H. Figure 2.
EPPO Global Database
This highly polyphagous species, commonly found both in the Old and New World, has caused significant economic damage as an invasive agricultural pest in Brazil since The goal of the present study is to provide a detailed morphological assessment of adults and immature stages of H. The biology data were acquired during four full life cycles, and observations on general behavior, nocturnal habits of larvae and adults, and sensitivity of larvae to humidity were recorded. Larval chaetotaxy differs between the first and the remaining instars, which bear L2 on the meso- and metathorax and L3 on A3 through A6, along with conspicuous chalazae and longitudinal bands. Important morphological characters of this species include the following: eggs with four micropylar openings, lined with 12 cells arranged in the shape of a rosette; pupa adecticous and obtect, with prominent spiracles; adults with the distal antennomere striate. Adults exhibit sexual dimorphism in the number of setae on the frenulum and spines on the prothoracic leg.
Helicoverpa armigera: current status and future perspectives in Brazil.
In maize, both species tend to infest the ear. The introduction of H. In this study, larval occurrence and proportion of these species in maize was assessed in three regions of Brazil during three crop seasons. Interaction between the species was evaluated in interspecific and intraspecific scenarios under laboratory and field conditions. In western Bahia, H. Larva of H.