scholarly journals Behavioral and Developmental Responses of Habrobracon hebetor (Hymenoptera: Braconidae) to Larvae of Helicoverpa armigera (Lepidoptera: Noctuidae) Inoculated With Various Concentrations of Bacillus thuringiensis var. kurstaki (Bacillales: Bacillacae)

2020 ◽  
Vol 20 (6) ◽  
Author(s):  
Rahim Allahyari ◽  
Shahram Aramideh ◽  
J P Michaud ◽  
Mohammad Hassan Safaralizadeh ◽  
Mohammad Reza Rezapanah
Keyword(s):  
Biological Control ◽  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Choice Test ◽  
Habrobracon Hebetor ◽  
Combined Application ◽  
Joint Application ◽  
Immature Development ◽  
Helicoverpa Armígera ◽  
Parasitoid Development

Abstract Bacillus thuringiensis Berliner subsp. kurstaki (Btk) and Habrobracon hebetor Say are both biological control agents of Helicoverpa armigera Hubner. The present study evaluated their compatibility for combined application against this pest by examining the acceptability of Btk-inoculated hosts for H. hebetor females and testing for negative life-history impacts on developing progeny. Second-instar H. armigera larvae fed for 72 h on potted chickpea plants treated with three concentrations of Btk (LC15, LC35, and LC70) and were then used in bioassays of parasitoid development and parasitism behavior. Survival of parasitoids was significantly reduced, and immature development prolonged, on hosts fed chickpea plants treated with LC35 and LC70  Btk, but not on plants treated with LC15  Btk. Parasitoids failed to discriminate against hosts treated with LC15 or LC35  Btk in choice tests, but attacked fewer hosts treated with LC70  Btk, paralyzing and parasitizing more healthy hosts, and laying more eggs on them. In contrast, a no-choice test revealed that more hosts treated with LC35 and LC70  Btk were paralyzed compared with control or LC15-treated hosts, but the numbers of hosts parasitized and eggs laid did not vary among Btk treatments. Thus, females required an experience with healthy hosts, as they had in the choice test, to discriminate against diseased ones. We conclude that H. hebetor and Btk are compatible for joint application against H. armigera, which could potentially improve biological control of this pest.

Negative Life History Impacts for Habrobracon hebetor (Hymneoptera: Braconidae) that Develop in Bollworm Larvae Inoculated with Helicoverpa armigera Nucleopolyhedrovirus

2020 ◽  
Vol 113 (4) ◽  
pp. 1648-1655 ◽  
Author(s):  
Rahim Allahyari ◽  
Shahram Aramideh ◽  
J P Michaud ◽  
Mohammad Hassan Safaralizadeh ◽  
Mohammad Reza Rezapanah
Keyword(s):  
Helicoverpa Armigera ◽  
Population Doubling ◽  
Intrinsic Rate Of Increase ◽  
Dependent Manner ◽  
Net Reproductive Rate ◽  
Habrobracon Hebetor ◽  
Laboratory Conditions ◽  
Joint Application ◽  
Rate Of Increase ◽  
Helicoverpa Armígera

Abstract Cotton bollworm, Helicoverpa armigera Hubner, is a cosmopolitan polyphagous pest of many crops. Habrobracon hebetor Say and Helicoverpa armigera nucleopolyhedrovirus (HearNPV) are two important biocontrol agents used to manage this pest, sometimes in combination. We evaluated the sublethal effects of HearNPV on H. hebetor life table parameters under laboratory conditions when its host (second instar H. armigera) was treated with HearNPV, and tested H. hebetor females for their ability to discriminate against inoculated hosts. Emergence of adults reared as solitary larvae was reduced by half on LC30-inoculated larvae compared to controls, but not on LC5 or LC15-inoculated hosts. Low concentrations (LC5, LC15, and LC30) of HearNPV had no effects on overall parasitoid developmental time, but longevity and lifetime fecundity was reduced for females emerging from hosts receiving the LC30 treatment. Net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ) were all decreased in a concentration-dependent manner in the LC15 and LC30 treatments, as were female life expectancy, age-specific survivorship (lx), and age-specific fecundity (mx), whereas population doubling time (DT) increased. Parasitoids did not discriminate against LC15-inoculated larvae in choice or no-choice tests, but parasitized more LC50-inoculated hosts than controls in the choice test, with no significant differences in total numbers of eggs laid in either case. Although parasitoids suffered some loss of fitness in HearNPV-inoculated hosts under these laboratory conditions, these agents still appear compatible for joint application against H. armigera under field conditions, provided parasitoid releases are made 2 d after NPV application.

scholarly journals Bacillus thuringiensis Bel Protein Enhances the Toxicity of Cry1Ac Protein to Helicoverpa armigera Larvae by Degrading Insect Intestinal Mucin

2009 ◽  
Vol 75 (16) ◽  
pp. 5237-5243 ◽  
Author(s):  
Shangling Fang ◽  
Li Wang ◽  
Wei Guo ◽  
Xia Zhang ◽  
Donghai Peng ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Trichoplusia Ni ◽  
Knockout Mutant ◽  
Gene Encoding ◽  
In Vitro Degradation ◽  
Intestinal Mucin ◽  
Helicoverpa Armígera ◽  
Cry1ac Protein

ABSTRACT Bacillus thuringiensis has been used as a bioinsecticide to control agricultural insects. Bacillus cereus group genomes were found to have a Bacillus enhancin-like (bel) gene, encoding a peptide with 20 to 30% identity to viral enhancin protein, which can enhance viral infection by degradation of the peritrophic matrix (PM) of the insect midgut. In this study, the bel gene was found to have an activity similar to that of the viral enhancin gene. A bel knockout mutant was constructed by using a plasmid-free B. thuringiensis derivative, BMB171. The 50% lethal concentrations of this mutant plus the cry1Ac insecticidal protein gene were about 5.8-fold higher than those of the BMB171 strain. When purified Bel was mixed with the Cry1Ac protein and fed to Helicoverpa armigera larvae, 3 μg/ml Cry1Ac alone induced 34.2% mortality. Meanwhile, the mortality rate rose to 74.4% when the same amount of Cry1Ac was mixed with 0.8 μg/ml of Bel. Microscopic observation showed a significant disruption detected on the midgut PM of H. armigera larvae after they were fed Bel. In vitro degradation assays showed that Bel digested the intestinal mucin (IIM) of Trichoplusia ni and H. armigera larvae to various degrading products, similar to findings for viral enhancin. These results imply Bel toxicity enhancement depends on the destruction of midgut PM and IIM, similar to the case with viral enhancin. This discovery showed that Bel has the potential to enhance insecticidal activity of B. thuringiensis-based biopesticides and transgenic crops.

scholarly journals DAYA PATOGENESITAS Helicoverpa armigera Nuclear Polyhedrosis Virus HaNPV SETELAH TERKENA RADIASI SINAR ULTRAVIOLET

2000 ◽  
Vol 6 (1) ◽  
pp. 65-70
Author(s):  
Mahanani Tri Asri ◽  
Isnawati Isnawati
Keyword(s):  
Biological Control ◽  
Helicoverpa Armigera ◽  
Nuclear Polyhedrosis Virus ◽  
Uv Light ◽  
Ultra Violet ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Helicoverpa Armígera ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis

This research is about pathogen capacity of the Helicoverpa armigera nuclear Polyhedrosis Virus (HaNPV) after irradiation by ultra violet (UV) light. The HaNPV is the one kind of the virus which attack the insect Helicoverpa armigera-attacker the some species of the crop life tobacco, cotton, potato, tomato. Because of that the HaNPV can be used as the biological control of the pest. Some researcher stated that the pathogen capacity of the HaNPV is decrease if the virus was expose in the ultra violet (UV) light. Because of the fact the virus in not useful as the biological control of the pest in the land corp. This research to test the statement. Laboratory experimental was done to tested the pathogen capacity of the HaNPV after irradiation treatment by the ultra violet light. The intensity of the UV light in this experiment were 28.7 lux, 97.3 lux, and 127.4 lux with the lighting period were 0, 1, 3, 6, 9, 12, and 15. The result of the research stated that the pathogen capacity of the HaNPV was not influenced by ultra violet light. So the virus is still useful as the biological control of the pest in the land crop.

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