scholarly journals Resistance to insecticides in Heliothine Lepidoptera: a global view

1998 ◽  
Vol 353 (1376) ◽  
pp. 1735-1750 ◽  
Author(s):  
A. R. McCaffery
Keyword(s):  
Helicoverpa Zea ◽  
Resistance Management ◽  
Corn Earworm ◽  
Tobacco Budworm ◽  
Current Status ◽  
Controversial Issues ◽  
Mechanisms Of Resistance ◽  
Pyrethroid Insecticides ◽  
Global View ◽  
The Status

The status of resistance to organophosphate, carbamate, cyclodiene and pyrethroid insecticides in the heliothine Lepidoptera is reviewed. In particular, resistance in the tobacco budworm, Heliothis virescens , and the corn earworm, Helicoverpa zea , from the New World, and the cotton bollworm, Helicoverpa armigera , from the Old World, are considered in detail. Particular emphasis has been placed on resistance to the most widely used of these insecticide groups, the pyrethroids. In each case, the incidence and current status of resistance are considered before a detailed view of the mechanisms of resistance is given. Controversial issues regarding the nature of mechanisms of resistance to pyrethroid insecticides are discussed. The implications for resistance management are considered.

scholarly journals The nucleopolyhedroviruses of Rachiplusia ou and Anagrapha falcifera are isolates of the same virus

1999 ◽  
Vol 80 (10) ◽  
pp. 2793-2798 ◽  
Author(s):  
Robert L. Harrison ◽  
Bryony C. Bonning
Keyword(s):  
Heliothis Virescens ◽  
Helicoverpa Zea ◽  
European Corn Borer ◽  
Biological Activities ◽  
Corn Earworm ◽  
Tobacco Budworm ◽  
Predicted Amino Acid Sequence ◽  
Corn Borer ◽  
Anagrapha Falcifera ◽  
Relationship Of

The 7·8 kb EcoRI-G fragment of Rachiplusia ou multicapsid nucleopolyhedrovirus (RoMNPV), containing the polyhedrin gene, was cloned and sequenced. The sequence of the fragment was 92·3% identical to the sequence of the corresponding region in the Autographa californica (Ac)MNPV genome. A comparison of the EcoRI-G sequence with other MNPV sequences revealed that RoMNPV was most closely related to AcMNPV. However, the predicted amino acid sequence of RoMNPV polyhedrin shared more sequence identity with the polyhedrin of Orygia pseudotsugata MNPV. In addition, the RoMNPV sequence was almost completely identical (99·9%) to a previously published 6·3 kb sequence of Anagrapha falcifera MNPV (AfMNPV). The Eco RI and HindIII restriction fragment profiles of RoMNPV and AfMNPV also were nearly identical, with an additional EcoRI band detected in RoMNPV DNA. Bioassays of these viruses with three different hosts (the European corn borer, Ostrinia nubilalis H übner, the corn earworm, Helicoverpa zea Boddie, and the tobacco budworm, Heliothis virescens Fabricius) failed to detect any differences in the biological activities of RoMNPV and AfMNPV. These results indicate that RoMNPV and AfMNPV are different isolates of the same virus. The taxonomic relationship of Ro/AfMNPV and AcMNPV is discussed.

Alternatives to Pyrethroids for Managing Corn Earworm in Sweet Corn, Seed Corn, Tomatoes and Peppers

2007 ◽  
Vol 8 (1) ◽  
pp. 60 ◽  
Author(s):  
Richard Weinzierl
Keyword(s):  
Management Practices ◽  
Potential Problem ◽  
Sweet Corn ◽  
Commercial Production ◽  
Corn Earworm ◽  
Current Status ◽  
Pyrethroid Insecticides ◽  
Corn Seed ◽  
Seed Corn ◽  
Management Alternatives

To date, there are no reports of widespread failures of pyrethroid insecticides to control the corn earworm in midwestern North America. However, H. zea resistance to pyrethroids is a potential problem. If resistance compromises pyrethroid effectiveness, adopting or developing alternative management practices will be essential. This paper summarizes the current status of management alternatives for H. zea, specifically in commercial production of sweet corn, seed corn, tomatoes, and peppers. Accepted for publication 26 October 2006. Published 19 July 2007.

Bionomics of the Fall Armyworm (Lepidoptera: Noctuidae) and Its Ectoparasitic Nematode, Noctuidonema guyanense, in South Georgia

1996 ◽  
Vol 31 (2) ◽  
pp. 209-217
Author(s):  
C. E. Rogers ◽  
O. G. Marti ◽  
L. D. Chandler ◽  
A. M. Simmons
Keyword(s):  
Spodoptera Frugiperda ◽  
Heliothis Virescens ◽  
Helicoverpa Zea ◽  
Fall Armyworm ◽  
Corn Earworm ◽  
Cotton Bollworm ◽  
Tobacco Budworm ◽  
Beet Armyworm ◽  
South Georgia ◽  
Lepidoptera Noctuidae

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a perennial immigrant pest of several crops in south Georgia. Moths of S. frugiperda commonly are infested by an ectoparasitic nematode, Noctuidonema guyanense Remillet and Silvain in the Southeast. The seasonal chronology and natural association of these species are reported for Tift Co. from 1988 to 1994. Seasonal influxes of non-infested moths usually arrive in late April and dissipate in early November. Seasonal influxes of infested male moths follow the initial immigrants by 4 to 6 wks and disappear in the fall from 1 to 2 mos earlier than the general moth populations. Feral male moths that are moderately worn and infested by N. guyanense weigh less than moderately worn, non-infested males. Noctuidonema guyanense infests moths of several species of noctuids, but it has not been found on the cotton bollworm/corn earworm [Helicoverpa zea (Boddie)], tobacco budworm [Heliothis virescens (Fab.)], or beet armyworm [S. exigua (Hubner)].

Evidence for Decreasing Helicoverpa zea Susceptibility to Pyrethroid Insecticides in the Midwestern United States

2007 ◽  
Vol 8 (1) ◽  
pp. 57 ◽  
Author(s):  
W. D. Hutchison ◽  
E. C. Burkness ◽  
B. Jensen ◽  
B. R. Leonard ◽  
J. Temple ◽  
...  
Keyword(s):  
United States ◽  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Survival Rates ◽  
Field Tests ◽  
Corn Earworm ◽  
High Survival ◽  
Vegetable Crops ◽  
Pyrethroid Insecticides ◽  
Midwestern United States

The corn earworm (CEW), Helicoverpa zea (Boddie), is a highly mobile pest of numerous field and vegetable crops in much of North America. In the Midwestern United States, CEW is a voracious pest of several high-value vegetable crops, including sweet corn, tomatoes, and snap beans, and seed corn grown for the field corn industry. Historically, synthetic pyrethroid insecticides have been cost-effective and have provided excellent control of CEW, with control of larvae in sweet corn exceeding 90%. However, since 2000 pyrethroids have only provided 35 to 45% control in field tests conducted in the Midwest, as indicated by small-plot sweet corn efficacy trials. During 2005, the four most commonly used pyrethroids averaged only 19.3 to 37.3% control of CEW (mean of 5 trials in Minnesota, Wisconsin, Illinois, and Indiana). In addition, the survival of moths exposed to the standard pyrethroid, cypermethrin, using the Adult Vial Test (AVT), indicated high survival rates (44 to 66% at 5 μg cypermethrin and up to 45% survival at 10 μg). These levels are similar to, or higher than recent AVT results from Louisiana and Texas. These states reflect two possible “source” regions of late-season CEW that likely migrate north to the Midwestern states each summer. These results, including the stability of resistance each year in the Midwest, are discussed within the context of developing and expanding a North American resistance monitoring and management network. Accepted for publication 3 June 2007. Published 19 July 2007.

scholarly journals Populations of Helicoverpa zea (Boddie) in the Southeastern United States are Commonly Resistant to Cry1Ab, but Still Susceptible to Vip3Aa20 Expressed in MIR 162 Corn

Toxins ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 63 ◽  
Author(s):  
Ying Niu ◽  
Isaac Oyediran ◽  
Wenbo Yu ◽  
Shucong Lin ◽  
Marcelo Dimase ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Corn Earworm ◽  
Current Status ◽  
Bt Corn ◽  
Bt Crops ◽  
Bt Toxin ◽  
Resistance Evolution ◽  
Major Pest ◽  
The Impact ◽  
The U.S

The corn earworm, Helicoverpa zea (Boddie), is a major pest targeted by pyramided Bacillus thuringiensis (Bt) corn and cotton in the U.S. Cry1Ab is one of the first insecticidal toxins used in Bt crops, while Vip3A is a relatively new toxin that has recently been incorporated into Cry corn with event MIR 162 and Cry cotton varieties to generate pyramided Bt traits targeting lepidopteran pests including H. zea. The objectives of this study were to determine the current status and distribution of the Cry1Ab resistance, and evaluate the susceptibility to Vip3Aa20 expressed in MIR 162 corn in H. zea in the southeastern U.S. During 2018 and 2019, 32 H. zea populations were collected from non-Bt corn (19 populations), Cry corn (12), and Cry/Vip3A cotton (1) across major corn areas in seven southeastern states of the U.S. Susceptibility of these populations to Cry1Ab and Vip3Aa20 was determined using diet-overlay bioassays. Compared to a known susceptible insect strain, 80% of the field populations were 13- to >150-fold resistant to Cry1Ab, while their response to Vip3Aa20 ranged from >11-fold more susceptible to 9-fold more tolerant. Mean susceptibility to each Bt toxin was not significantly different between the two groups of the populations collected from non-Bt and Bt crops, as well as between the two groups of the populations collected during 2018 and 2019. The results show that resistance to Cry1Ab in H. zea is widely distributed across the region. However, the Cry1Ab-resistant populations are not cross-resistant to Vip3Aa20, and H. zea in the region is still susceptible to the Vip3Aa20 toxin. Vip3Aa20 concentrations between 5 and 10 µg/cm2 may be used as diagnostic concentrations for susceptibility monitoring in future. Additional studies are necessary to elucidate the impact of the selection with Bt corn on resistance evolution in H. zea to Vip3A cotton in the U.S.

Susceptibility of Five Plant Defoliators to Celery Looper (Lepidoptera: Noctuidae) Nuclear Polyhedrosis Virus

1996 ◽  
Vol 31 (3) ◽  
pp. 306-314
Author(s):  
Walter Solomon ◽  
Lavone Lambert ◽  
M. R. Bell
Keyword(s):  
Helicoverpa Zea ◽  
Nuclear Polyhedrosis Virus ◽  
Relative Activity ◽  
Corn Earworm ◽  
Tobacco Budworm ◽  
Beet Armyworm ◽  
Anticarsia Gemmatalis ◽  
Velvetbean Caterpillar ◽  
Polyhedrosis Virus ◽  
Nuclear Polyhedrosis

Bioassays were conducted to determine the susceptibility of five lepidopteran defoliators to a nuclear polyhedrosis virus (NPV) isolated from the celery looper, Anagrapha falcifera (Kirby). Tobacco budworm, Heliothis virescens (F.), exhibited the greatest susceptibility, LC50 = 2,328PIB/ml, and velvetbean caterpillar, Anticarsia gemmatalis (Hübner), exhibited the least susceptibility, LC50 = 5,176,038 PIB/ml, after 7 d of feeding at the 5 × 104 PIB/ml dosage. Corn earworm, Helicoverpa zea (Boddie), soybean looper, Pseudoplusia includens (Walker), and beet armyworm, Spodoptera exigua (Hübner), expressed intermediate levels of susceptibility, LC50 - 11,742, 14,195, 14,614 respectively, after 7 d of feeding at the 5 × 104 PIB/ml dosage. These results were consistent at days 10 and 14 indicating the relative activity of the virus against each species.

scholarly journals Improving Risk Assessment of Noctuid Pests at North American Ports and Farms by Differentiating Egg Morphology

2019 ◽  
Vol 112 (5) ◽  
pp. 443-450
Author(s):  
Carlos A Blanco ◽  
Armando Rosario-Lebron ◽  
Cheryle A O’Donnell ◽  
Maribel Portilla ◽  
Connor Gullbronson ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Ornamental Plants ◽  
The United States ◽  
Corn Earworm ◽  
Tobacco Budworm ◽  
International Commerce ◽  
Optical Electron ◽  
Old World Bollworm ◽  
Egg Morphology ◽  
Plant Inspection

Abstract Heliothine eggs are commonly found on agricultural commodities and ornamental plants transported through domestic and international commerce. Tobacco budworm [Chloridea (Heliothis) virescens (F.)], Chloridea subflexa (Guenée), and the corn earworm [Helicoverpa zea (Boddie)] are indigenous pests of the American continent. Interceptions of the Old World bollworm [Helicoverpa armigera (Hübner)] at various ports of entry into the United States have been detected due to the invasion of this pest in South America, adding to the complexity and importance of decision making at plant inspection stations. The ability to distinguish the eggs of C. virescens from C. subflexa and Helicoverpa species is a critical component for conducting risk assessments by quarantine authorities, taxonomists, and crop consultants. We developed a simple, rapid (~60 min), inexpensive ($0.06 per sample), and accurate (100% reliability) technique to distinguish C. virescens eggs from the possibility of being H. armigera based on the presence, number, and/or size of aeropyle holes on the primary ribs of eggs, near the micropylar rosette. In this location, aeropyles were easily visible at 40× magnification in 213 fresh and ethanol-preserved C. virescens eggs once treated with Hoyer’s solution. A small number of C. subflexa had one or two aeropyles on a few of the primary ribs, whereas no aeropyles were found on 411 H. zea and 269 H. armigera eggs analyzed using optical, electron, and confocal microscopy. We conclude that in most cases multiple aeropyle holes positively identify H. virescens eggs from H. zea or H. armigera, and C. subflexa. This technique potentially will reduce the number of specimens that need to be sent for molecular identification thereby saving program time and resources.

Potential Impact of Pyrethroid Resistance in Helicoverpa zea to the Midwest Processing Industry: Sweet Corn and Snap Beans

2007 ◽  
Vol 8 (1) ◽  
pp. 61 ◽  
Author(s):  
Brian R. Flood ◽  
Thomas L. Rabaey
Keyword(s):  
Helicoverpa Zea ◽  
Sweet Corn ◽  
Pyrethroid Resistance ◽  
Corn Earworm ◽  
Pyrethroid Insecticides ◽  
Snap Beans ◽  
Early Instar ◽  
Production Areas ◽  
Treatment Window

Midwest food processors are well positioned to avoid major crop losses, and product contamination resulting from pyrethroid resistance in corn earworm (CEW), Helicoverpa zea (Boddie). However, we do recognize risks associated with late-season plantings, particularly for sweet corn and snap beans. CEW usually migrate into the production areas by late July to mid-August. Crops at risk for most Midwest locations primarily include sweet corn planted after 10 June and snap beans planted after 10 July (about 25% of the Midwest acreage). Pyrethroid insecticides continue to be the commercial standard, with alternative chemistries either ineffective or more expensive. The CEW “treatment window” for sweet corn is from row tassel to dark brown silk and, for snap beans, from bloom to 10 days before harvest. In sweet corn, CEW is only vulnerable as an adult, egg, or early instar feeding on the silk. If left untreated, or with insecticide failure, we anticipate a loss of about one square inch of kernels per larva (2 cases/ton of final cut-corn product). The loss of kernels and the creation of black kernels from contamination associated with feeding injury are estimated to have a market cost in excess of $100/acre, or $6 million for Midwest sweet corn and snap beans. We currently have no effective alternative insecticides for CEW for either crop. In the short term, processors will likely use higher rates of pyrethroids, shorter intervals, and/or additional treatments. Long term, we will increasingly rely on a “process-out” approach to husk out, wash out, and vision-sort larval contaminants and damaged kernels. Accepted for publication 23 February 2007. Published 19 July 2007.

Pyrethroid Insecticide Efficacy Against Tobacco Budworm (Lepidoptera: Noctuidae) in North Carolina Flue-Cured Tobacco: Implications for Insecticide Resistance Management

2007 ◽  
Vol 42 (4) ◽  
pp. 582-588
Author(s):  
M.R. Abney ◽  
C.E. Sorenson ◽  
P.S. Southern
Keyword(s):  
North Carolina ◽  
Heliothis Virescens ◽  
Resistance Management ◽  
Tobacco Budworm ◽  
Feeding Damage ◽  
Pyrethroid Insecticides ◽  
Significant Control ◽  
Insecticide Efficacy ◽  
Lambda Cyhalothrin ◽  
Lepidoptera Noctuidae

Foliar applications of 3 pyrethroid insecticides were made to flue-cured tobacco and compared with Bacillus thuringiensis Berliner (Bt) bait and sprays of acephate and spinosad for control of the tobacco budworm, Heliothis virescens (F.), in 2001, 2002, and 2003. Lambda-cyhalothrin, cyfluthrin, and bifenthrin provided significant control of tobacco budworm when compared with untreated checks in all 3 yrs; however, they were generally less efficacious than the other insecticides tested. The level of control among the pyrethroids differed significantly within years but was inconsistent from year to year. The severity of tobacco budworm feeding damage was recorded for individual plants in each treatment, and damage averaged over pyrethroid treatments was 54.17% lower than the untreated control in 2001 and 79.84% lower in 2003. Pyrethroid treatments had no impact on yield of cured leaf in 2001 or 2003 compared with controls. The use of pyrethroid insecticides in flue-cured tobacco will increase the selection pressure placed on tobacco budworm populations in North Carolina. As a result, resistance to this class of insecticides may develop at an accelerated rate.

scholarly journals Dental Applications of Carbon Nanotubes

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4423
Author(s):  
Marco A. Castro-Rojas ◽  
Yadira I. Vega-Cantu ◽  
Geoffrey A. Cordell ◽  
Aida Rodriguez-Garcia
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Oral Cavity ◽  
Current Status ◽  
Glass Ionomer ◽  
Oral Infections ◽  
Functional Behavior ◽  
The Status ◽  
Comprehensive Survey ◽  
Dental Applications

Glass ionomer cements and resin-based composites are promising materials in restorative dentistry. However, their limited mechanical properties and the risk of bulk/marginal fracture compromise their lifespan. Intensive research has been conducted to understand and develop new materials that can mimic the functional behavior of the oral cavity. Nanotechnological approaches have emerged to treat oral infections and become a part of scaffolds for tissue regeneration. Carbon nanotubes are promising materials to create multifunctional platforms for dental applications. This review provides a comprehensive survey of and information on the status of this state-of-the-art technology and describes the development of glass ionomers reinforced with carbon nanotubes possessing improved mechanical properties. The applications of carbon nanotubes in drug delivery and tissue engineering for healing infections and lesions of the oral cavity are also described. The review concludes with a summary of the current status and presents a vision of future applications of carbon nanotubes in the practice of dentistry.

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