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 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 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 Bionomics of slender burnished brass (Thysanoplusia orichalcea [Fabricius, 1775], Lepidoptera: Noctuidae) on potato (Solanum tuberosum L.) in Kashmir

2021 ◽  
Vol 117 (1) ◽  
pp. 1
Author(s):  
Gousul NISA ◽  
Abdul A. BUHROO
Keyword(s):  
Solanum Tuberosum ◽  
Solanum Tuberosum L ◽  
Larval Instar ◽  
Head Capsule ◽  
Adult Longevity ◽  
Growth Ratio ◽  
Head Capsule Width ◽  
Geometrical Progression ◽  
Lepidoptera Noctuidae ◽  
Total Life

<p>A study on biology, morphometrics and geometrical progression of <em>Thysanoplusia orichalcea</em> was conducted on <em>Solanum tuberosum</em>under laboratory conditions. Different stages viz., egg, larva, pupa and adult of <em>T. orichalcea</em> were observed for their duration and morphometric measurements. The pest depicted five larval instars and moultedfour times during the entire period. The average pre oviposition and oviposition period was observed to be 3.80 and 2.80 days respectively.Further, fecundity ranges between 381.0-400.0 with an average of 388.0 eggs. The mean incubation period was found to be 4.2 days. The average larval, pre pupal and pupal period was completed in 23.1, 1.4 and 9.5 days respectively. While mean adult longevity on <em>S. tuberosum</em> was 7.45 days. The total life cycle was completed in 41.0-51.0 days with an average of 45.65 days. Moreover, mean head capsule width of first, second, third, fourth and fifth larval instar was found to be 0.33, 0.54, 0.88, 1.46 and 2.24 mm respectivelywith Dyar’s ratio/ growth ratio of 1.63 mm. The expected head capsule width of first, second, third, fourth and fifth larval instar wasobserved as 0.33, 0.53, 0.86, 1.40 and 2.28 mm respectively.</p>

scholarly journals Evaluation of Metarhizium rileyi Farlow (Samson) impregnated with azadirachtin and indoxacarb against Helicoverpa armigera (Hubner)

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Bhisham Dev ◽  
Subhash Chander Verma ◽  
Prem Lal Sharma ◽  
Rajeshwar Singh Chandel ◽  
Mahesh Balaso Gaikwad ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Helicoverpa Armigera ◽  
Developmental Stages ◽  
Management Program ◽  
Median Lethal Concentration ◽  
Larval Instars ◽  
Metarhizium Rileyi ◽  
Mortality Response ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae

Abstract Background Entomopathogenic fungi are the most versatile having a wide host range, capable of infecting insects at different developmental stages. In the present study, Metarhizium rileyi, at the concentrations of 102, 103, 104, 105, 106, 107 and 108 conidia/ml and sub-lethal concentrations of azadirachtin (1.02 and 1.53 ppm) and indoxacarb (0.72 ppm) were evaluated against the 1st, 2nd, 3rd, 4th and 5th larval instars of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) under laboratory conditions. Results M. rileyi applied at 106 conidia/ml caused a maximum mortality of 83.33 and 80.00% of 1st and 2nd larval instars of H. armigera, respectively. The maximum mortality of 3rd, 4th and 5th larval instars of H. armigera with 108 conidia/ml of M. rileyi was 83.33, 76.67 and 53.33%, respectively. When M. rileyi blended with azadirachtin at 1.02 ppm, the highest mortality rate of 86.21% at 106 conidia/ml against 2nd instar larvae was resulted. Similarly, M. rileyi applied at 108 conidia /ml mixed with azadirachtin (1.53 ppm) showed 89.66% mortality of 3rd instar larvae. The 2nd instar larvae treated with M. rileyi at 106 conidia/ml, mixed with indoxacarb (0.72 ppm), the corrected mortality rate was 82.14%. Concentration mortality response of 3rd instar larvae to M. rileyi blended with indoxacarb (0.72 ppm) was 85.71% at 108 conidia/ml. The median lethal concentration (LC50) values were 5.51 × 103, 1.86 × 104, 2.81 × 105 and 5.55 × 105 conidia/ml for 1st, 2nd, 3rd and 4th larval instars, respectively, after 7 days of treatment. M. rileyi when mixed with sub-lethal concentrations of azadirachtin (1.02 ppm) and indoxacarb (0.72 ppm) resulted LC50 values of 1.09 × 104 conidia/ml and 1.37 × 104 conidia/ml against 2nd instar larvae, respectively, after 24 hours. Similarly, M. rileyi mixed with sub-lethal concentrations of azadirachtin (1.53 ppm) and indoxacarb (0.72 ppm) resulted LC50 values of 3.12 × 108 and 3.06 × 105 conidia/ml against 3rd instar larvae, respectively, after 24 hours. The study revealed that the susceptibility of larvae decreased in case of large larval instars. Conclusions M. rileyi can be utilized as one of the component of Integrated Pest Management Program for the eco-friendly management of H. armigera. As the application of M. rileyi @ 107 conidia/ml alone or in combination with azadirachtin (1.02 and 1.53 ppm) or indoxacarb (0.72 ppm) resulted to the highest mortality.

Incidence of Helicoverpa armigera (Lepidoptera: Noctuidae) and its natural enemies on smallholder crops in Kenya

1993 ◽  
Vol 83 (3) ◽  
pp. 321-328 ◽  
Author(s):  
H. van den Berg ◽  
M. J. W. Cock ◽  
G. I. Oduor ◽  
E. K. Onsongo
Keyword(s):  
Helicoverpa Armigera ◽  
Heliothis Armigera ◽  
Population Densities ◽  
Parasitoid Species ◽  
Larval Parasitoid ◽  
Total Percentage ◽  
Four Seasons ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Experimental Plots

AbstractSmallholder crops (sunflower, maize, sorghum and cotton) were grown in experimental plots at seven sites, representing different agricultural zones of Kenya, over four seasons. Helicoverpa armigera (Hübner) (formerly Heliothis armigera) only occasionally achieved population densities sufficient to cause obvious damage to the crops, and was virtually absent from the coastal sites. At the inland sites, infestation and mortality levels varied greatly. Information is presented on the incidence of H. armigera, and the identity, distribution and frequency of its common parasitoids and (potential) predators, sampled in the experimental plots. Trichogrammatoidea spp., egg parasitoids, and Linnaemya longirostris (Macquart), a tachinid late-larval parasitoid, were the most common parasitoid species, but total percentage parasitism was rather low. Of the large complex of predators, only anthocorids and ants (predominantly Pheidole spp., Myrmicaria spp. and Camponotus spp.) were sufficiently common and widespread to be of importance in suppressing H. armigera. The abundance of predators fluctuated widely between sites, but anthocorids were most abundant at the western sites.

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