Effect of ultrasound on acetylcholinesterase activity in Helicoverpa armigera (Lepidoptera: Noctuidae)

2008 ◽  
Vol 140 (5) ◽  
pp. 563-568 ◽  
Author(s):  
Yu-Ping Zha ◽  
Fen Xu ◽  
Qi-Cai Chen ◽  
Chao-Liang Lei
Keyword(s):  
Enzyme Activity ◽  
Helicoverpa Armigera ◽  
Cholinergic System ◽  
Developmental Stages ◽  
Acetylcholinesterase Activity ◽  
Behavioral Effects ◽  
Stress Effects ◽  
Helicoverpa Armígera ◽  
Commercial Device ◽  
Lepidoptera Noctuidae

AbstractIt is well known that noctuid moths respond to ultrasound frequencies produced by insectivorous bats performing a series of evasive maneuvers such as loops, dives, rolls, and turns. Certain ultrasound frequencies may be considered an environmental stress factor for these moths, causing physiological and behavioral effects. We investigated changes in acetylcholinesterase activity of Helicoverpa armigera (Hübner) exposed to ultrasound produced from a commercial device (LHC20). Our results indicated that stress effects on acetylcholinesterase activity resulting from exposure to ultrasound do not differ according to sex, but effects on different developmental stages of H. armigera differ significantly depending on duration of exposure. Enzyme activity increased in adults after 20 min exposure to ultrasound and decreased in pupae after 30 and 50 min exposure. Enzyme activity in larvae was reduced after 20 min and increased after 40 and 60 min. The results of this study also indicate that stress caused by exposure to ultrasound could modulate the cholinergic system in H. armigera.

scholarly journals Fluctuation patterns of different developmental stages of Helicoverpa armigera (Lepidoptera: Noctuidae) on chickpea (Cicer arietinum) and their relationship with the environment

2005 ◽  
Vol 16 (4) ◽  
Author(s):  
Zahid Ali Shah ◽  
Muhammad Shahzad
Keyword(s):  
Relative Humidity ◽  
Environmental Factors ◽  
Helicoverpa Armigera ◽  
Relative Frequency ◽  
Developmental Stages ◽  
Frequency Of Occurrence ◽  
Pod Borer ◽  
Helicoverpa Armígera ◽  
Lepidoptera Noctuidae ◽  
Eggs And Larvae

The relative frequency of occurrence of different developmental stages of gram pod borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), and the dependence of its developmental stages on environmental factors, are crucial in the population management. The densities of eggs and larvae were low from December to mid-February due to prevailing cold. Owing to optimum environmental conditions, increasing densities were observed throughout March and they droppped again during the first week of April. The densities of eggs and different larval instars of H. armigera were significantly positively correlated with temperature, and significantly negatively correlated with the average morning relative humidity (RH;%) but not with the average evening RH (%).

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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