The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Nigel J. Armes - One of the best experts on this subject based on the ideXlab platform.
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Comparative status of insecticide resistance in the Helicoverpa and Heliothis species (Lepidoptera: Noctuidae) of south India
Bulletin of Entomological Research, 1996Co-Authors: Deepak R. Jadhav, Nigel J. ArmesAbstract:Helicoverpa armigera (Hubner), H. assulta Guenee and Heliothis peltigera (Denis & Schiffermuller) were collected as mixed populations from safflower and the wild host Datura metel, from Patancheru, Andhra Pradesh, India, in 1992 and 1993, and their toxicological responses to insecticides determined. Both Helicoverpa armigera strains were highly resistant to cypermethrin, fenvalerate, endosulfan and quinalphos insecticides, based on resistance ratios relative to laboratory reared susceptible strains. There was no evidence of resistance development in H. assulta and Heliothis peltigera to the same chemicals. Light trap data collected from 1974 to 1987 showed that Helicoverpa armigera was at least 100 × more abundant than the other two species over most of the cropping season. Peak catches of H. assulta and Heliothis peltigera were confined to defined times in the season, corresponding with the flowering and fruiting periods of their respective host plants; August-October for Helicoverpa assulta and November-December for Heliothis peltigera. Helicoverpa armigera on the other hand, because of its high polyphagy on commercial and wild hosts, was abundant between August and April. Resistance has not developed in H. assulta and Heliothis peltigera in southern India, probably because of their restricted host range, limiting exposure to insecticides.
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Comparative status of insecticide resistance in the Helicoverpa and Heliothis species (Lepidoptera: Noctuidae) of south India
Bulletin of Entomological Research, 1996Co-Authors: Deepak R. Jadhav, Nigel J. ArmesAbstract:AbstractHelicoverpa armigera (Hübner), H. assulta Guenée and Heliothis peltigera (Denis & Schiffermüller) were collected as mixed populations from safflower and the wild host Datura metel, from Patancheru, Andhra Pradesh, India, in 1992 and 1993, and their toxicological responses to insecticides determined. Both Helicoverpa armigera strains were highly resistant to cypermethrin, fenvalerate, endosulfan and quinalphos insecticides, based on resistance ratios relative to laboratory reared susceptible strains. There was no evidence of resistance development in H. assulta and Heliothis peltigera to the same chemicals. Light trap data collected from 1974 to 1987 showed that Helicoverpa armigera was at least 100 × more abundant than the other two species over most of the cropping season. Peak catches of H. assulta and Heliothis peltigera were confined to defined times in the season, corresponding with the flowering and fruiting periods of their respective host plants; August-October for Helicoverpa assulta and November-December for Heliothis peltigera. Helicoverpa armigera on the other hand, because of its high polyphagy on commercial and wild hosts, was abundant between August and April. Resistance has not developed in H. assulta and Heliothis peltigera in southern India, probably because of their restricted host range, limiting exposure to insecticides.
Winfield L. Sterling - One of the best experts on this subject based on the ideXlab platform.
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Dislodgement of Heliothis zea (Lepidoptera: Noctuidae) eggs from cotton due to rain and wind: a predictive model
Ecological Modelling, 1991Co-Authors: Gregg S. Nuessly, Albert W. Hartstack, John A. Witz, Winfield L. SterlingAbstract:Abstract This study provides mechanisms and means for estimating Heliothis zea egg mortality to rain and wind under field conditions. Building on laboratory studies with simulated weather factors, equations are presented to describe the dislodgement of Heliothis zea eggs from cotton plants by the action of rain and wind alone and in combination. These estimates can be used as correction factors in studies of Heliothis spp. egg predation and as an aid in making management decisions for this pest.
Deepak R. Jadhav - One of the best experts on this subject based on the ideXlab platform.
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Comparative status of insecticide resistance in the Helicoverpa and Heliothis species (Lepidoptera: Noctuidae) of south India
Bulletin of Entomological Research, 1996Co-Authors: Deepak R. Jadhav, Nigel J. ArmesAbstract:Helicoverpa armigera (Hubner), H. assulta Guenee and Heliothis peltigera (Denis & Schiffermuller) were collected as mixed populations from safflower and the wild host Datura metel, from Patancheru, Andhra Pradesh, India, in 1992 and 1993, and their toxicological responses to insecticides determined. Both Helicoverpa armigera strains were highly resistant to cypermethrin, fenvalerate, endosulfan and quinalphos insecticides, based on resistance ratios relative to laboratory reared susceptible strains. There was no evidence of resistance development in H. assulta and Heliothis peltigera to the same chemicals. Light trap data collected from 1974 to 1987 showed that Helicoverpa armigera was at least 100 × more abundant than the other two species over most of the cropping season. Peak catches of H. assulta and Heliothis peltigera were confined to defined times in the season, corresponding with the flowering and fruiting periods of their respective host plants; August-October for Helicoverpa assulta and November-December for Heliothis peltigera. Helicoverpa armigera on the other hand, because of its high polyphagy on commercial and wild hosts, was abundant between August and April. Resistance has not developed in H. assulta and Heliothis peltigera in southern India, probably because of their restricted host range, limiting exposure to insecticides.
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Comparative status of insecticide resistance in the Helicoverpa and Heliothis species (Lepidoptera: Noctuidae) of south India
Bulletin of Entomological Research, 1996Co-Authors: Deepak R. Jadhav, Nigel J. ArmesAbstract:AbstractHelicoverpa armigera (Hübner), H. assulta Guenée and Heliothis peltigera (Denis & Schiffermüller) were collected as mixed populations from safflower and the wild host Datura metel, from Patancheru, Andhra Pradesh, India, in 1992 and 1993, and their toxicological responses to insecticides determined. Both Helicoverpa armigera strains were highly resistant to cypermethrin, fenvalerate, endosulfan and quinalphos insecticides, based on resistance ratios relative to laboratory reared susceptible strains. There was no evidence of resistance development in H. assulta and Heliothis peltigera to the same chemicals. Light trap data collected from 1974 to 1987 showed that Helicoverpa armigera was at least 100 × more abundant than the other two species over most of the cropping season. Peak catches of H. assulta and Heliothis peltigera were confined to defined times in the season, corresponding with the flowering and fruiting periods of their respective host plants; August-October for Helicoverpa assulta and November-December for Heliothis peltigera. Helicoverpa armigera on the other hand, because of its high polyphagy on commercial and wild hosts, was abundant between August and April. Resistance has not developed in H. assulta and Heliothis peltigera in southern India, probably because of their restricted host range, limiting exposure to insecticides.
Donald D. Ourth - One of the best experts on this subject based on the ideXlab platform.
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Purification and characterization of lysozyme from hemolymph of Heliothis virescens larvae.
Biochemical and biophysical research communications, 1996Co-Authors: Timothy D. Lockey, Donald D. OurthAbstract:Lysozyme is an important antibacterial protein in the insect defense system. Lysozyme was isolated from hemolymph of Heliothis virescens larvae using gel filtration and ion-exchange chromatography. Heliothis lysozyme had a molecular mass of 16,000 daltons by SDS-PAGE. Using acid gel electrophoresis, Heliothis lysozyme migrated faster than egg white lysozyme. The pI of Heliothis lysozyme was estimated as greater than 9.5. Heliothis lysozyme had specific bactericidal activity against three Gram-positive bacteria but no activity against Escherichia coli. The bactericidal activity was stable at 100 degrees C at pH 3.0 after 60 min incubation, but was labile at 100 degrees C at pH 6.8 after 60 min incubation. Heliothis lysozyme was an inducible protein that increased 9 times when comparing unvaccinated with vaccinated larvae. Lysozyme from H. virescens was more similar in molecular mass, heat sensitivity and pH sensitivity to lysozyme isolated from Galleria mellonella and Bombyx mori than to lysozyme isolated from Hyalophora cecropia.
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Formation of Pores in Escherichia coli Cell Membranes by a Cecropin Isolated from Hemolymph of Heliothis virescens Larvae
European journal of biochemistry, 1996Co-Authors: Timothy D. Lockey, Donald D. OurthAbstract:The insect humoral defense system produces antibacterial peptides called cecropins. Cecropins were initially isolated from Hyalophora cecropia pupae and have since been isolated and identified in various insects. In this study, we have isolated and identified a cecropin from Heliothis virescens larvae. Rabbit IgG were raised against synthetic cecropin B. Affinity chromatography with the rabbit anti-(cecropin B) IgG was used to isolate a cecropin from hemolymph of H. virescens larvae. Acid gel electrophoresis followed by a bacterial-overlay analysis showed that Heliothis cecropin is a basic peptide of low molecular mass with bactericidal activity against Escherichia coli K12 D31. Heliothis cecropin is therefore analogous to synthetic cecropin B. One unresolved issue concerning cecropins and other antibiotic peptides is the mode of action by which they kill bacteria. By means of electron microscopy and immunocyto-chemistry with gold-labeled rabbit anti-cecropin IgG, binding of purified and synthetic cecropin to the cell membranes of E. coli K12 D31 cells was observed. Small lesions in the cell membrane were seen that had a diameter of 9.6 nm and internal pore of 4.2 nm. The Heliothis cecropin was found to be a pore-forming molecule that causes lesions in the cell membrane of E. coli K12 D31. The lesions lead to leakage of cytoplasmic contents and death of bacteria.
Gregg S. Nuessly - One of the best experts on this subject based on the ideXlab platform.
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Dislodgement of Heliothis zea (Lepidoptera: Noctuidae) eggs from cotton due to rain and wind: a predictive model
Ecological Modelling, 1991Co-Authors: Gregg S. Nuessly, Albert W. Hartstack, John A. Witz, Winfield L. SterlingAbstract:Abstract This study provides mechanisms and means for estimating Heliothis zea egg mortality to rain and wind under field conditions. Building on laboratory studies with simulated weather factors, equations are presented to describe the dislodgement of Heliothis zea eggs from cotton plants by the action of rain and wind alone and in combination. These estimates can be used as correction factors in studies of Heliothis spp. egg predation and as an aid in making management decisions for this pest.