scholarly journals Some Natural Plant Extracts Having Biocide Activities against the American Bollworm <i>Helicoverpa armigera</i> (Lepidoptera: Noctuidae)

2019 ◽  
Vol 07 (01) ◽  
pp. 10-20 ◽  
Author(s):  
Aziza Sharaby ◽  
Zamzam M. Al Dhafar
Keyword(s):  
Plant Extracts ◽  
Helicoverpa Armigera ◽  
Natural Plant ◽  
American Bollworm ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

scholarly journals Changes in protein profile and encapsulation avoiding responses of entomopathogenic nematode in the American bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Istkhar ◽  
Ashok Kumar Chaubey
Keyword(s):  
Helicoverpa Armigera ◽  
Entomopathogenic Nematode ◽  
Protein Profile ◽  
Control Group ◽  
Host Immune System ◽  
Native Page ◽  
High Pathogenicity ◽  
American Bollworm ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

AbstractThe American bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is a highly destructive agriculture pest of worldwide importance. The aim of the present study was to infect H. armigera larvae with entomopathogenic nematode juveniles for hematological study of proteins and encapsulation responses to evaluate using this nematode for the management of this pest. Total protein estimation and the electrophoretic profiling carried out in the hemolymph showed a high pathogenicity of Steinernema abbasi to H. armigera. The control group survived and succeeded to develop to adults, while the infected ones died within 24 h. An increase in the protein contents in the total and plasma hemolymph was observed just after 3 h of infection with an increase at 6 h and 9 h as symptoms of early defence of the insect. SDS-PAGE profile also showed an evolvement of a protein band of 46 kDa. No self-association or aggregation and binding of other proteins were found in the hemolymph as revealed by Native-PAGE. The encapsulation avoidance rate of nematode juvenile gave good results with (> 33%) in 2 IJs/larva to 5% in 20 IJs/larva doses at24 h post infection. Loss of hemolymph proteins continued for more than 24 h with a very low recognition of nematode rate in hemolymph, followed by the death of larvae within 48 h, which proved the high pathogenicity of S. abbasi and suppression of host immune system of H. armigera.

scholarly journals Need for growing non-Bt cotton refugia to overcome Bt resistance problem in targeted larvae of the cotton bollworms, Helicoverpa armigera and Pectinophora gossypiella

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Muhammad Rafiq Shahid ◽  
Muhammad Farooq ◽  
Muhammad Shakeel ◽  
Misbah Ashraf ◽  
Zia Ullah Zia ◽  
...  
Keyword(s):  
Helicoverpa Armigera ◽  
Larval Mortality ◽  
Pectinophora Gossypiella ◽  
Bt Cotton ◽  
Insect Larvae ◽  
Plant Parts ◽  
Arthropod Species ◽  
Bt Resistance ◽  
American Bollworm ◽  
Helicoverpa Armígera

Abstract Background The effectiveness of Bacillus thuringiensis (Bt) cotton against target arthropod larvae is decreasing day by day. The comparative effect of Bt expression among Bt cotton varieties and different plant parts was observed against the cotton bollworms: Helicoverpa armigera and Pectinophora gossypiella larvae. Results In the present study, larval mortality of H. armigera was higher than P. gossypiella among selected Bt cultivars. Median lethal concentration (LC50) values were 8.91, 13.4, 14.0, and 36.4 for P. gossypiella, while 5.91, 4.04, 2.37, and 8.26 for H. armigera of FH-142, MNH-886, IR-3701, and FH-Lalazar, respectively. These values depicted that P. gossypiella had more Bt resistance problem than H. armigera larvae. The host range of both targeted insect larvae was different from each other due to the polyphagous feeding nature of the larvae of H. armigera that feed on different host plants, but P. gossypiella attacked only cotton with monophagous feeding habit. It was also notable from results that Bt expression in reproductive parts where the attacked pink bollworm was lower than the American bollworm, so the former had the maximum chance of resistance due to repeated exposure to Bt. Conclusions It was concluded that farmers be advised to follow the practice of growing non-Bt as a refuge crop to reduce the problem of Bt resistance in the target arthropod species.

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