scholarly journals Insecticidal Activities of Chloramphenicol Derivatives Isolated from a Marine Alga-Derived Endophytic Fungus, Acremonium vitellinum, against the Cotton Bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2995 ◽  
Author(s):  
Dan Chen ◽  
Peng Zhang ◽  
Tong Liu ◽  
Xiu-Fang Wang ◽  
Zhao-Xia Li ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Helicoverpa Armigera ◽  
Endophytic Fungus ◽  
Marine Alga ◽  
Cotton Bollworm ◽  
Ionization Mass ◽  
Chemical Structures ◽  
Lc50 Value ◽  
Helicoverpa Armígera ◽  
Insecticidal Activities

A great deal of attention has been focused on the secondary metabolites produced by marine endophytic fungi, which can be better alternatives to chemicals, such as biopesticides, for control of polyphagous pests. On the basis of its novel biocontrol attributes, chemical investigation of a marine alga-derived endophytic fungus, Acremonium vitellinum, resulted in the isolation of three chloramphenicol derivatives (compounds 1–3). Their chemical structures were elucidated by detailed analysis of their nuclear magnetic resonance spectra, high-resolution electrospray ionization mass spectrometry, and by comparison with the data available in the literature. In this paper, compound 2 was firstly reported as the natural origin of these fungal secondary metabolites. The insecticidal activities of compounds 1–3 against the cotton bollworm, Helicoverpa armigera, were evaluated. The natural compound 2 presented considerable activity against H. armigera, with an LC50 value of 0.56 ± 0.03 mg/mL (compared to matrine with an LC50 value of 0.24 ± 0.01 mg/mL). Transcriptome sequencing was used to evaluate the molecular mechanism of the insecticidal activities. The results presented in this study should be useful for developing compound 2 as a novel, ecofriendly and safe biopesticide.

Broad-scale suppression of cotton bollworm, Helicoverpa armigera (Lepidoptera: Noctuidae), associated with Bt cotton crops in Northern New South Wales, Australia

2016 ◽  
Vol 107 (2) ◽  
pp. 188-199 ◽  
Author(s):  
G.H. Baker ◽  
C.R. Tann
Keyword(s):  
Host Plant ◽  
Helicoverpa Armigera ◽  
Cotton Bollworm ◽  
Bt Cotton ◽  
Cotton Production ◽  
Bt Toxin ◽  
Pheromone Trapping ◽  
Eastern Australia ◽  
Helicoverpa Armígera ◽  
Broad Scale

AbstractThe cotton bollworm, Helicoverpa armigera, is a major pest of many agricultural crops in several countries, including Australia. Transgenic cotton, expressing a single Bt toxin, was first used in the 1990s to control H. armigera and other lepidopteran pests. Landscape scale or greater pest suppression has been reported in some countries using this technology. However, a long-term, broad-scale pheromone trapping program for H. armigera in a mixed cropping region in eastern Australia caught more moths during the deployment of single Bt toxin cotton (Ingard®) (1996–2004) than in previous years. This response can be attributed, at least in part, to (1) a precautionary cap (30% of total cotton grown, by area) being applied to Ingard® to restrict the development of Bt resistance in the pest, and (2) during the Ingard® era, cotton production greatly increased (as did that of another host plant, sorghum) and H. armigera (in particular the 3rd and older generations) responded in concert with this increase in host plant availability. However, with the replacement of Ingard® with Bollgard II® cotton (containing two different Bt toxins) in 2005, and recovery of the cotton industry from prevailing drought, H. armigera failed to track increased host-plant supply and moth numbers decreased. Greater toxicity of the two gene product, introduction of no cap on Bt cotton proportion, and an increase in natural enemy abundance are suggested as the most likely mechanisms responsible for the suppression observed.

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