Chrysodeixis chalcites nucleopolyhedrovirus (ChchNPV): Natural occurrence and efficacy as a biological insecticide on young banana plants in greenhouse and open-field conditions on the Canary Islands

ABSTRACTAChrysodeixis chalcitessingle-nucleocapsid nucleopolyhedrovirus wild-type isolate from the Canary Islands, Spain, named ChchSNPV-TF1 (ChchTF1-wt), appears to have great potential as the basis for a biological insecticide for control of the pest. An improved understanding of the genotypic structure of this wild-type strain population should facilitate the selection of genotypes for inclusion in a bioinsecticidal product. Eight genetically distinct genotypes were clonedin vitro: ChchTF1-A to ChchTF1-H. Quantitative real-time PCR (qPCR) analysis confirmed that ChchTF1-A accounted for 36% of the genotypes in the wild-type population. In bioassays, ChchTF1-wt occlusion bodies (OBs) were significantly more pathogenic than any of the component single-genotype OBs, indicating that genotype interactions were likely responsible for the pathogenicity phenotype of wild-type OBs. However, the wild-type population was slower killing and produced higher OB yields than any of the single genotypes alone. These results strongly suggested that the ChchTF1-wt population is structured to maximize its transmission efficiency. Experimental OB mixtures and cooccluded genotype mixtures containing the most abundant and the rarest genotypes, at frequencies similar to those at which they were isolated, revealed a mutualistic interaction that restored the pathogenicity of OBs. In OB and cooccluded mixtures containing only the most abundant genotypes, ChchTF1-ABC, OB pathogenicity was even greater than that of wild-type OBs. The ChchTF1-ABC cooccluded mixture killed larvae 33 h faster than the wild-type population and remained genotypically and biologically stable throughout five successive passagesin vivo. In conclusion, the ChchTF1-ABC mixture shows great potential as the active ingredient of a bioinsecticide to controlC. chalcitesin the Canary Islands.

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Effects of several UV-protective substances on the persistence of the insecticidal activity of the Alphabaculovirus of Chrysodeixis chalcites (ChchNPV-TF1) on banana (Musa acuminata, Musaceae, Colla) under laboratory and open-field conditions

PLoS ONE ◽

10.1371/journal.pone.0250217 ◽

2021 ◽

Vol 16 (5) ◽

pp. e0250217

Author(s):

Taylan Çakmak ◽

Oihane Simón ◽

Mehmet Bora Kaydan ◽

Denis Achiri Tange ◽

Agueda Mª. González Rodríguez ◽

...

Keyword(s):

Open Field ◽

Green Tea ◽

Field Experiments ◽

Uv Light ◽

Photochemical Efficiency ◽

Field Conditions ◽

Leaf Surfaces ◽

Occlusion Bodies ◽

Chrysodeixis Chalcites ◽

Lepidoptera Noctuidae

Alphabaculovirus of Chrysodeixis chalcites (ChchNPV-TF1) has been investigated as a useful bioinsecticide against C. chalcites (Esper) (Lepidoptera: Noctuidae) in banana crops. This study investigated the effects of several substances on the persistence of ChchNPV-TF1 under field conditions in the Canary Islands. Natural photoprotective substances, such as moringa, cacao, green tea, benzopurpurine, charcoal, iron dioxide, benzimidazole, kaolinite, and bentonite, were first evaluated under laboratory conditions using a Crosslinker as UV light source at 200 J/cm2. The photoprotective substances were divided into three groups: low protection (0–8%; kaolinite), intermediate protection (48–62%; green tea, moringa, bentonite and cacao) and high protection (87–100%; charcoal, iron ioxide). Benzopurpurine and benzimidazole did not provide any photoprotective effects. Two of the substances that yielded the best results, 1% cacao and 1% charcoal, were selected for the open-field experiment in a banana plantation. The persistence of ChchNPV-TF1 OBs (occlusion bodies) on leaf surfaces with sunlight exposure was analysed by comparing the initial mortality of 2nd instar C. chalcites larvae with the mortality observed at various intervals postapplication. The mortality rates decreased over time in all treatments and were always higher in the UV-protective substance-treated parcels. The 1% charcoal treatment exhibited the highest protection in both the laboratory and field experiments. No specific interference of UV-protective substances on the maximum photochemical efficiency of banana plants was observed under field conditions.

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The degradation of imidacloprid and thiamethoxam in sugar beet plants in open field conditions and in glasshouses

10.1603/ice.2016.113718 ◽

2016 ◽

Author(s):

Zrinka Drmic

Keyword(s):

Sugar Beet ◽

Open Field ◽

Field Conditions

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Application of Bio-Friendly Formulations of Chitinase-Producing Streptomyces cellulosae Actino 48 for Controlling Peanut Soil-Borne Diseases Caused by Sclerotium rolfsii

Journal of Fungi ◽

10.3390/jof7030167 ◽

2021 ◽

Vol 7 (3) ◽

pp. 167

Author(s):

Gaber Abo-Zaid ◽

Ahmed Abdelkhalek ◽

Saleh Matar ◽

Mai Darwish ◽

Muhammad Abdel-Gayed

Keyword(s):

Open Field ◽

Biocontrol Agent ◽

Sclerotium Rolfsii ◽

Dry Weight ◽

Culture Broth ◽

Field Conditions ◽

Damping Off ◽

Mycelium Growth ◽

Particle Size Analyzer ◽

Cell Pellet

Of ten actinobacterial isolates, Streptomyces cellulosae Actino 48 exhibited the strongest suppression of Sclerotium rolfsii mycelium growth and the highest chitinase enzyme production (49.2 U L−1 min−1). The interaction between Actino 48 and S. rolfsii was studied by scanning electron microscope (SEM), which revealed many abnormalities, malformations, and injuries of the hypha, with large loss of S. rolfsii mycelia density and mass. Three talc-based formulations with culture broth, cell-free supernatant, and cell pellet suspension of chitinase-producing Actino 48 were characterized using SEM, Fourier transform infrared spectroscopy (FTIR), and a particle size analyzer. All formulations were evaluated as biocontrol agents for reducing damping-off, root rot, and pods rot diseases of peanut caused by S. rolfsii under greenhouse and open-field conditions. The talc-based culture broth formulation was the most effective soil treatment, which decreased the percentage of peanut diseases under greenhouse and open-field conditions during two successive seasons. The culture broth formulation showed the highest increase in the dry weight of peanut shoots, root systems, and yielded pods. The transcriptional levels of three defense-related genes (PR-1, PR-3, and POD) were elevated in the culture broth formulation treatment compared with other formulations. Subsequently, the bio-friendly talc-based culture broth formulation of chitinase-producing Actino 48 could potentially be used as a biocontrol agent for controlling peanut soil-borne diseases caused by S. rolfsii.

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