scholarly journals Efficacy of Helicoverpa Armigera Nucleopolyhedrovirus on Soybean for Control of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Arkansas Agriculture

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 91
Author(s):  
Joseph L. Black ◽  
Gus M. Lorenz ◽  
Aaron J. Cato ◽  
Nick R. Bateman ◽  
Nicholas J. Seiter
Keyword(s):  
Helicoverpa Armigera ◽  
Helicoverpa Zea ◽  
Larval Instar ◽  
Instar Larva ◽  
Naturally Occurring ◽  
Action Threshold ◽  
Helicoverpa Armígera ◽  
New Formulation ◽  
Mean Time ◽  
Lepidoptera Noctuidae

Helicoverpa armigera nucleopolyhedrovirus (HearNPV) is a naturally occurring virus commercially produced for control of Heliothines, including Helicoverpa zea. One drawback with using this virus for control has been the slower time to mortality compared with synthetic insecticides. However, a new formulation (Heligen®) has anecdotally been thought to result in quicker mortality than previously observed. The objective of this study was to evaluate percent defoliation, the efficacy of HearNPV on mortality for each H. zea larval instar, and the potential for control of a second infestation. Fourteen days after the first infestation, all plants were re-infested with a second instar larva to simulate a second infestation. Helicoverpa armigera nucleopolyhedrovirus was effective at killing 1st–3rd instars, resulting in 99% mortality over 4–6 days. However, 4th and 5th instar mortality only reached 35%. Second infestation larvae died between 3.4 and 3.8 days, significantly faster than the 1st infestation of 2nd instars, which had a mean time to mortality of 4.9 days. An increase in mortality rate is probably due to increasing viral concentrations after viral replication within the first hosts. Final defoliation percentages were significantly smaller in the treated plants versus the untreated plants. Only 3rd and 4th instar larvae caused percent defoliation to exceed the current Arkansas action threshold of 40%. Helicoverpa armigera nucleopolyhedrovirus in the Heligen formulation can control 1st–3rd instars within 4–6 days, while keeping defoliation below the action threshold of 40%.

scholarly journals Desenvolvimento de Helicoverpa spp. em milho Bt com expressão de diferentes proteínas

2016 ◽  
Vol 51 (5) ◽  
pp. 537-544
Author(s):  
Christiane Almeida dos Santos ◽  
Rosangela Cristina Marucci ◽  
Tatiane Aparecida Nascimento Barbosa ◽  
Octavio Gabryel Araujo ◽  
José Magid Waquil ◽  
...  
Keyword(s):  
Helicoverpa Armigera ◽  
Helicoverpa Zea ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

Resumo: O objetivo deste trabalho foi avaliar os aspectos biológicos de Helicoverpa zea e Helicoverpa armigera (Lepidoptera: Noctuidae) em híbridos de milho com expressão de diferentes proteínas. Foram avaliadas as proteínas Cry1F, Cry1A(b), Cry1A.105 + Cry2Ab2 e Vip3A e seus respectivos isogênicos convencionais. As larvas foram alimentadas com espiguetas de milho Bt e convencional, trocadas a cada dois dias. Os parâmetros avaliados foram: sobrevivência 48 horas após eclosão, sobrevivência larval, peso de larvas e de pupas, período de desenvolvimento larval e período pré-imaginal. Observou-se efeito significativo da interação entre evento de milho Bt e espécie de Helicoverpa para todas as variáveis biológicas avaliadas. Larvas de H. armigera apresentaram maior sobrevivência 48 horas após eclosão em milho expressando a proteína Cry1F e a Vip3 em relação a H. zea. O período letal foi maior em H. armigera do que em H. zea, mas, em milho com expressão da proteína Cry1A(b), foi quatro vezes menor. Não houve sobrevivente para ambas as espécies de Helicoverpa em nenhum dos híbridos Bt avaliados. Nos isogênicos convencionais, o índice de adaptação de H. armigera foi superior ao de H. zea, o que indica maior facilidade de adaptação ao ambiente dessa espécie.

scholarly journals Determination of Helicoverpa armigera (Lepidoptera: Noctuidae) larval instars and age based on head capsule width and larval weight

2017 ◽  
Vol 15 ◽  
pp. 53 ◽  
Author(s):  
D. G. Stavridis ◽  
C. G. Ipsilandis ◽  
P. C. Katarachias ◽  
P. G. Milonas ◽  
A. A. Ifoulis ◽  
...  
Keyword(s):  
Body Weight ◽  
Helicoverpa Armigera ◽  
Larval Instar ◽  
Head Capsule ◽  
Head Width ◽  
Larval Instars ◽  
Head Capsule Width ◽  
Helicoverpa Armígera ◽  
L1 And L2 ◽  
Lepidoptera Noctuidae

Larνae of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) were reared in laboratory conditions (26°C, 16:8 L:D) and measurements of larval head capsule width, and body weight, were used in order to determine the boundaries of larval instars. Larvae of Η. armigera completed development in 5 to 7 instars. Head capsule width could predict the larval instar only for Ll. The upper boundary of head width for L1 was 0.4mm. Body weight could predict both L1 and L2 larval instars. Boundaries between L1-L2 instars were found to be 1 mg and for L2-L3 5,5 mg. Correlation and regression analysis suggest that a combination of head capsule width and body weight can predict both larval instars and chronological age under constant conditions in the laboratory.

scholarly journals ACTION THRESHOLD LEVELS OF HELICOVERPA ARMIGERA (HBN.) ON COTTON AT DIFFERENT STAGES OF PLANT GROWTH

2018 ◽  
Vol 6 (3) ◽  
pp. 39-48
Author(s):  
Amir Abdullahi Yousif Malik ◽  
Elamin Mohamed Elamin
Keyword(s):  
Helicoverpa Armigera ◽  
Threshold Level ◽  
Growth Stages ◽  
Protection Measures ◽  
Threshold Levels ◽  
Action Threshold ◽  
Cotton Plants ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Recommended Action

The African bollworm, Helicoverpa armigera (Hbn.) (Lepidoptera: Noctuidae), is the most important cotton pest in all the cotton growing areas of the Sudan and most of the protection measures are directed for its management. The previous action threshold level for chemical control interference was increased in 1993 from 10 larvae and/or eggs /100 plants to 30 eggs or 10 larvae/100 plants and no spray to be conducted before flowering advances. This level was being subject to revision since 1999. Studies conducted at the Gezira Research Farm during 2001/2002, 2002/2003, 2003/2004, 2004/2005 and 2012/2013 were carried out on this regard at growth stages of cotton plants, i.e.  Pre-flowering, flowering and bolls formation stages and the consequence on yield. Barac. (67) B cultivar, Gossypium hirsutum, was used. The action threshold levels were 10, 15, 20 eggs and/or larvae/100 plants and 30 eggs or 10 larvae/100 plants, in addition to untreated and Helicoverpa infestation free as control treatments. The results of damage on fruiting bodies (squares, flowers and bolls) and seed cotton yield showed that there were no significant differences between the tested action threshold levels in the pre-flowering and the flowering stages of cotton growth as compared to the control treatments.  From the yields and number of sprays in the treatments it can be concluded that the already recommended action threshold 30 eggs or 10 larvae/100 plants is still be applied when flowering advances and bolls formed. Moreover, the standing action threshold seems lower than the actual level. Therefore, it is suggested to investigate higher action threshold than that in current use.

scholarly journals Comparative Performance of Helicoverpa armigera (Lepidoptera: Noctuidae) on Chickpea and Faba Bean

2018 ◽  
Vol 11 (1) ◽  
pp. 29
Author(s):  
Tarekegn Fite ◽  
Tadele Tefera ◽  
Mulugeta Negeri ◽  
Tebekew Damte ◽  
Waktole Sori ◽  
...  
Keyword(s):  
Helicoverpa Armigera ◽  
Faba Bean ◽  
Larval Instar ◽  
Larval Period ◽  
Agricultural Pests ◽  
Prepupal Stage ◽  
Suitable Host ◽  
Comparative Performance ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) is one of the most economically important agricultural pests of chickpea in Asia and Africa. Though most of the H. armigera biology was studied on chickpea, yet better understanding on fababean was still important. The present study was conducted to better understand the life cycle of H. armigera reared on chickpea and faba bean under laboratory conditions via the development of age-stage life tables. The results of life table study indicated that the highest survival rate was during the late larval instar on both hosts followed by early instars. High mortality was during prepupal stage on chickpea and during the 5th larval instar on faba bean. Total larval period was 15.8 days on chickpea and 15.1 days on faba bean. Larvae reared on chickpea exhibited the longest (14.9 days) period of mean total pupal and pre-oviposition durations. Maximum fecundity and eggs viability were recorded from insect reared on chickpea. The current result revealed that chickpea was the more suitable host for reproduction and survival of H. armigera than faba bean under laboratory condition.

scholarly journals Comparative Toxicity of Helicoverpa armigera and Helicoverpa zea (Lepidoptera: Noctuidae) to Selected Insecticides

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 431 ◽  
Author(s):  
Fernando R. da Silva ◽  
Dario Trujillo ◽  
Oderlei Bernardi ◽  
Jose Carlos Verle Rodrigues ◽  
Woodward D. Bailey ◽  
...  
Keyword(s):  
Puerto Rico ◽  
Acute Toxicity ◽  
Insecticide Resistance ◽  
Helicoverpa Armigera ◽  
Helicoverpa Zea ◽  
Corn Earworm ◽  
Median Lethal Concentration ◽  
Helicoverpa Armígera ◽  
Old World Bollworm ◽  
Lepidoptera Noctuidae

Until recently, the Old World bollworm (OWB) Helicoverpa armigera (Hübner) and the corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) were geographically isolated. Both species are major pests of agricultural commodities that are known to develop insecticide resistance, and they now coexist in areas where H. armigera invaded the Americas. This is the first study to compare the susceptibility of the two species to conventional insecticides. The susceptibility of third instar H. armigera and H. zea larvae to indoxacarb, methomyl, spinetoram, and spinosad was determined using a diet-overlay bioassay in a quarantine laboratory in Puerto Rico. Mortality was assessed at 48 h after exposure for up to eight concentrations per insecticide. Spinetoram exhibited the highest acute toxicity against H. armigera, with a median lethal concentration (LC50) of 0.11 µg a.i./cm2, followed by indoxacarb and spinosad (0.17 µg a.i./cm2 for both) and methomyl (0.32 µg a.i./cm2). Spinetoram was also the most toxic to H. zea (LC50 of 0.08 µg a.i./cm2), followed by spinosad (0.17 µg a.i./cm2) and methomyl (0.18 µg a.i./cm2). Indoxacarb was the least toxic to H. zea, with an LC50 of 0.21 µg a.i./cm2. These findings could serve as a comparative reference for monitoring the susceptibility of H. armigera and H. zea to indoxacarb, methomyl, spinetoram, and spinosad in Puerto Rico, and may facilitate the detection of field-selected resistance for these two species and their potential hybrids in areas recently invaded by H. armigera.

scholarly journals Battle in the New World: Helicoverpa armigera versus Helicoverpa zea (Lepidoptera: Noctuidae)

PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0167182 ◽  
Author(s):  
José P. F. Bentivenha ◽  
Silvana V. Paula-Moraes ◽  
Edson L. L. Baldin ◽  
Alexandre Specht ◽  
Ivana F. da Silva ◽  
...  
Keyword(s):  
Helicoverpa Armigera ◽  
Helicoverpa Zea ◽  
New World ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae
Sign in / Sign up

Export Citation Format

Share Document