scholarly journals Studies on the cold-hardiness and overwintering of Spodoptera litura F. (Lepidoptera: Noctuidae). I. Viability of the insect under low temperatures.

1991 ◽  
Vol 35 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Hiroichi MATSUURA ◽  
Atsushi NAITO ◽  
Atsushi KIKUCHI
Keyword(s):  
Low Temperatures ◽  
Spodoptera Litura ◽  
Cold Hardiness ◽  
Lepidoptera Noctuidae

SURVIVAL OF PUPAE OF HELIOTHIS VIRESCENS AND HELIOTHIS ZEA (LEPIDOPTERA: NOCTUIDAE) AT LOW TEMPERATURES

1982 ◽  
Vol 114 (4) ◽  
pp. 289-301 ◽  
Author(s):  
Joseph E. Eger ◽  
John A. Witz ◽  
Albert W. Hartstack ◽  
Winfield L. Sterling
Keyword(s):  
Low Temperature ◽  
Exposure Time ◽  
Predictive Models ◽  
Low Temperatures ◽  
Heliothis Virescens ◽  
Cold Hardiness ◽  
Heliothis Zea ◽  
Geographic Locations ◽  
Lepidoptera Noctuidae

AbstractMortality of diapausing and non-diapausing pupae of Heliothis virescens (Fabricius) and H. zea (Boddie) at low temperatures was assessed in the laboratory. Comparison of the exposure time necessary to induce 50% mortality (LT50) indicated that survival of diapausing pupae was significantly higher than that of non-diapausing pupae. Similar comparisons showed no consistent significant differences in mortality of pupae from different geographic locations within Texas or in pupae preconditioned in several different ways. One exception was the response of pupae of H. virescens preconditioned to varying temperatures. This type of preconditioning appeared to increase the cold-hardiness of pupae at subfreezing temperatures. Contact moisture significantly decreased LT50 values of pupae of both species at sub-zero temperatures. Predictive models for low temperature mortality were developed for dry, diapausing pupae.

scholarly journals Pathogenicity of Metarhizium rileyi (Farlow) Kepler, S.A. Rehner and Humber isolates against Spodoptera litura (Fabricius) and their extracellular enzymatic activities

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Gurmehar Kaur Grewal ◽  
Neelam Joshi ◽  
Yadhu Suneja
Keyword(s):  
Spodoptera Litura ◽  
Larval Mortality ◽  
Screening Methods ◽  
Metarhizium Rileyi ◽  
Percent Mortality ◽  
Commercially Important ◽  
Extracellular Enzymatic Activities ◽  
Chemical Pesticides ◽  
Lepidoptera Noctuidae

Abstract Background Spodoptera litura (Fab.) (Lepidoptera: Noctuidae) is a serious agricultural pest that infests many commercially important crops of Southeast Asian countries. Indiscriminate use of chemical pesticides has led to various health hazards as well as insecticide resistance. Entomopathogenic fungi (EPF) provide an important alternative as biological control agents. Metarhizium rileyi is an EPF with a specific host range for lepidopteran pests. The present study aimed to identify virulent M. rileyi isolate against S. litura larvae and analyse their extracellular cuticle-degrading enzyme activities. Results Three M. rileyi isolates viz M. rileyi NIPHM, M. rileyi MTCC 4254 and M. rileyi MTCC 10395 formulations were evaluated at different concentrations against 2nd instar larvae of S. litura. A maximum percent mortality of 63.33% was recorded in M. rileyi NIPHM (12 g/l), followed by M. rileyi MTCC 4254 (58.33%) at the same concentration, 10 days post-treatment. Maximum means of chitinase, protease and lipase activities (0.44, 1.58 and 2.95 U/ml, respectively) were recorded in the case of M. rileyi NIPHM. Correlation analysis was positive between enzyme activity and larval mortality. Conclusions Metarhizium rileyi NIPHM recorded the highest enzymatic activity and exhibited the maximum mortality rate against 2nd instar larvae of S. litura, suggesting the possible role of these enzymes in the pathogenicity of the fungus. Further knowledge in this regard may help in the development of enzyme-based screening methods for selecting virulent fungal isolates for the eco-friendly management of crop pests.

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