Chemical insecticides have been commonly used to control agricultural pests, termites, and biological vectors such as mosquitoes and ticks. However, the harmful impacts of toxic chemical insecticides on the environment, the development of resistance in pests and vectors towards chemical insecticides, and public concern have driven extensive research for alternatives, especially biological control agents such as fungus and bacteria. In this review, the mode of infection of Metarhizium fungus on both terrestrial and aquatic insect larvae and how these interactions have been widely employed will be outlined. The potential uses of Metarhizium anisopliae and Metarhizium acridum biological control agents and molecular approaches to increase their virulence will be discussed.

https://www.mdpi.com/2309-608X/3/2/30/pdf

Mode of Infection of Metarhizium spp. Fungus and Their Potential as Biological Control Agents.

Baculoviruses are among the most studied insect pathogens. Members of Baculoviridae have a large double-stranded DNA genome within the nucleoprotein core of a rod-shaped virion. Baculovirus replication produces two different virion phenotypes: occlusion-derived virions, which initiate infection, and budded virions, which spread infection within the host. Baculoviruses have been isolated only from insects, and have a potential role in insect pest management. The development of cell culture systems and the application of molecular biology led to the development of baculoviruses as popular expression vectors. This chapter summarizes the current state of baculovirology, covering: baculovirus classification, taxonomy, and phylogeny; basic characteristics of baculovirus virions and viral occlusions; features of two unrelated groups of occluded viruses (entomopoxviruses and cypoviruses) and a related group of non-occluded viruses (nudiviruses); mechanisms of infection, gene expression, and replication; their pathology, ecology, and use as biopesticides; and potential new frontiers for study of this group of viruses.

Baculoviruses and Other Occluded Insect Viruses

Genetic variation and virulence of nucleopolyhedroviruses isolated worldwide from the heliothine pests Helicoverpa armigera, Helicoverpa zea, and Heliothis virescens.

Baculovirus genes modulating intracellular innate antiviral immunity of lepidopteran insect cells.

Cassava is a major staple, bio-energy and industrial crop in many parts of the developing world. In Southeast Asia, cassava is grown on >4 million ha by nearly 8 million (small-scale) farming households, under (climatic, biophysical) conditions that often prove unsuitable for many other crops. While SE Asian cassava has been virtually free of phytosanitary constraints for most of its history, a complex of invasive arthropod pests and plant diseases has recently come to affect local crops. We describe results from a region-wide monitoring effort in the 2014 dry season, covering 429 fields across five countries. We present geographic distribution and field-level incidence of the most prominent pest and disease invaders, introduce readily-available management options and research needs. Monitoring work reveals that several exotic mealybug and (red) mite species have effectively colonised SE Asia's main cassava-growing areas, occurring in respectively 70% and 54% of fields, at average field-level incidence of 27 ± 2% and 16 ± 2%. Cassava witches broom (CWB), a systemic phytoplasma disease, was reported from 64% of plots, at incidence levels of 32 ± 2%. Although all main pests and diseases are non-natives, we hypothesise that accelerating intensification of cropping systems, increased climate change and variability, and deficient crop husbandry are aggravating both organism activity and crop susceptibility. Future efforts need to consolidate local capacity to tackle current (and future) pest invaders, boost detection capacity, devise locally-appropriate integrated pest management (IPM) tactics, and transfer key concepts and technologies to SE Asia's cassava growers. Urgent action is needed to mobilise regional as well as international scientific support, to effectively tackle this phytosanitary emergency and thus safeguard the sustainability and profitability of one of Asia's key agricultural commodities. © 2016 Society of Chemical Industry.

Emerging pests and diseases of South-east Asian cassava: a comprehensive evaluation of geographic priorities, management options and research needs.

A newly cloned Helicoverpa armigera nucleopolyhedrovirus (HearNPV) from Kenya, HearNPV-NNg1, has a higher insecticidal activity than HearNPV-G4, which also exhibits lower insecticidal activity than HearNPV-C1. In the search for genes and/or nucleotide sequences that might be involved in the observed virulence differences among Helicoverpa spp. NPVs, the entire genome of NNg1 was sequenced and compared with previously sequenced genomes of G4, C1 and Helicoverpa zea single-nucleocapsid NPV (Hz). The NNg1 genome was 132,425 bp in length, with a total of 143 putative open reading frames (ORFs), and shared high levels of overall amino acid and nucleotide sequence identities with G4, C1 and Hz. Three NNg1 ORFs, ORF5, ORF100 and ORF124, which were shared with C1, were absent in G4 and Hz, while NNg1 and C1 were missing a homologue of G4/Hz ORF5. Another three ORFs, ORF60 (bro-b), ORF119 and ORF120, and one direct repeat sequence (dr) were unique to NNg1. Relative to the overall nucleotide sequence identity, lower sequence identities were observed between NNg1 hrs and the homologous hrs in the other three Helicoverpa spp. NPVs, despite containing the same number of hrs located at essentially the same positions on the genomes. Differences were also observed between NNg1 and each of the other three Helicoverpa spp. NPVs in the diversity of bro genes encoded on the genomes. These results indicate several putative genes and nucleotide sequences that may be responsible for the virulence differences observed among Helicoverpa spp., yet the specific genes and/or nucleotide sequences responsible have not been identified.

Comparative genomic sequence analysis of novel Helicoverpa armigera nucleopolyhedrovirus (NPV) isolated from Kenya and three other previously sequenced Helicoverpa spp. NPVs.

In search for local entomopathogenic nematode (EPN) species as a biological control agent of lepidopterous insect pests of corn, a survey for EPN in the major islands in the Philippines was conducted. Seven EPN populations from 279 soil samples were isolated using Ostrinia furnacalis, the key target insect pest of corn in the country, as bait. Analysis of the ITS1-5.8S-ITS2 ribosomal DNA sequence revealed the presence of Steinernema abbasi, Steinernema minutum , Steinernema tami , and Heterorhabditis indica . The pathogenicity of these EPN was tested in Ostrinia furnacalis , Spodoptera litura , and Helicoverpa armigera larvae under laboratory conditions. All the EPN isolates were pathogenic to the lepidopteran species with, H. indica PBCB and S. abbasi MBLB exhibiting the highest virulence (88%-99.33% and 90%-100% mortality, respectively) at 48 hr post infection (HPI) and thus, further studies were done on these two EPN. The highest penetration rate at 48 HPI was observed in H. armigera infected with S. abbasi MBLB (28.15%), while the lowest was in O. furnacalis infected with H. indica PBCB (14.25%). Nonetheless, based on LC 50 at 48 HPI, H. indica PBCB was most virulent to S. litura (8.89 IJ per larva), but not significantly different from O. furnacalis (10.52 IJ per larva). Steinernema abbasi MBLB was most virulent to O. furnacalis (10.98 IJ per larva), but not significantly different to S. litura (17.08 IJ per larva). LT 50 estimates showed that O. furnacalis was significantly the most susceptible to H. indica PBCB (21.90 hr) and S. abbasi (21.18 hr). Our results suggest that H. indica PBCB and S. abbasi MBLB are good candidates as biological control agents against these insect pests of corn. Moreover, O. furnacalis as alternative bait for EPN was discussed. To date, this is the most extensive research on Philippine EPN, comprised of wide sampling coverage, molecular identification and bioefficacy assays.

/pdf/molecular-identification-of-entomopathogenic-nematode-1rmil06vd0.pdf

Molecular Identification of Entomopathogenic Nematode Isolates from the Philippines and their Biological Control Potential Against Lepidopteran Pests of Corn.

A total of five new cell lines were established from Helicoverpa armigera; including KU-HaEmb1 (HaEmb1) and KU-HaEmb2 (HaEmb2) from embryos, KU-HaPO1 (HaPO1) and KU-HaPO2 (HaPO2) from pupal ovaries, and KU-HaAO1 (HaAO1) from adult ovaries. These cell lines were examined for their permissiveness for homologous H. armigera nucleopolyhedrovirus (HearNPV) and seven heterologous NPVs. Upon infection with HearNPV, the cell line HaAO1 yielded the highest productivity in terms of amounts of polyhedra, budded virus (BV), polyhedrin and viral DNA among the six cell lines, including the five newly established cell lines and the cell line from Helicoverpa zea (BCIRL-Hz-AM1), which is commonly used for in vitro studies and production of HearNPV. The cell lines HaPO1, HaPO2 and HaEmb2 were also permissive for HearNPV but they yielded lower productivity than that of the cell line HaAO1. Only the cell line HaEmb1 was nonpermissive for HearNPV infection among the cell lines established. Examination with seven heterologous NPVs showed that all the new cell lines continued to proliferate without any cytopathic effects (CPE), following infection with five NPVs from Bombyx mori, Hyphantria cunea, Lymantria dispar, Orgyia pseudotsugata and Spodoptera litura. Upon infection with NPVs from Autographa californica (AcMNPV) and Spodoptera exigua (SeMNPV), all the new cell lines, with the exception of HaAO1, manifested CPE to varying degrees, synthesizing significant amount of viral DNA. These cell lines, with the exception of AcMNPV-infected HaPO1 that produced significant amount of BVs, yielded negligible or very low level of BVs and polyhedrin following infection with AcMNPV and SeMNPV, indicating that they were semipermissive for these two NPVs. These results indicate that the newly established H. armigera cell line HaAO1 provide a promising candidate for in vitro production of HearNPV biopesticide, as well as a useful system for the analysis of molecular mechanisms of NPV-cell interactions.

Susceptibility of Newly Established Cell Lines from Helicoverpa armigera to Homologous and Heterologous Nucleopolyhedroviruses

The importance of fungal attack to acarina has been observed but not yet on Tetranychus kanzawai . When infected mite, either within in a same  species or even in a different  species of  entomopathigenic probably  have  similar signs and simptoms to mites.  Characteristic of entomopathogenic fungus to Tetranychus kanza-wai was investigated. Three selected isolates of Metarhizium anisopliae , from Philippines and Indonesia were evaluated. The following aspects were investigated: (1) Bioassay tes of virulence, (2) Koch Postulate and (3) Infection process on each fungus against mite. Virulence of  Metarhizium anisopliae was 1.4 X 10 3 , 7.2 X 10 2 , 5 X 10 2  PIB per ml on Ma4, Ma5 and Ma6, respectively. On Koch Postulates, Reinoculation and reisolation of all seven isolates from infected T. kanzawai showed definite signs of infection. This demonstrated its entomopathogenic capacity. In this experiment, adult mites were sprayed with 10 8 per ml concentrations of conidia observed under light microscope and Scanning Electron Microscopy (SEM). The result found  T. kanzawai was very susceptible to three isolates M . anisopliae . In the end of the trials, fungal growth was detectable as early as 2 until 4 days of observation. Infection process with microphoto-graph and Scanning Electro Microscopy showed attachment, germination and penetration, extrusion and conidiogenesis fungal form. Keywords: Infection, Tetranychus kanzawai , Metarhizium anisopliae , Light micros-copy, Scanning Electro Microscopy (SEM) Normal 0 false false false EN-US X-NONE X-NONE Normal 0 false false false EN-US X-NONE X-NONE

https://agrivita.ub.ac.id/index.php/agrivita/article/download/180/558

Barbara L. Caoili

Papers

Comparative genomic sequence analysis of novel Helicoverpa armigera nucleopolyhedrovirus (NPV) isolated from Kenya and three other previously sequenced Helicoverpa spp. NPVs.

Molecular Identification of Entomopathogenic Nematode Isolates from the Philippines and their Biological Control Potential Against Lepidopteran Pests of Corn.

Susceptibility of Newly Established Cell Lines from Helicoverpa armigera to Homologous and Heterologous Nucleopolyhedroviruses

INFECTION PROCESS OF ENTOMOPATHOGENIC FUNGI Metarhizium anisopliae IN THE Tetranychus kanzawai (KISHIDA) (TETRANYCHIDAE: ACARINA)

Transmission effect of entomopathogenic fungi on population of Tetanychus kanzawai (Kishida) (Tetranychidae: Acarina).