Document Type : Original Article
Authors
1 Department of Entomology and Plant Pathology university of Tehran
2 Department of Entomology and Plant Pathology , College of Aburaihan, University of Tehran
Abstract
The use of plant pesticides in pest management seems necessary due to the widespread use of chemical pesticides, which has led to environmental damage. Plant extracts are mainly obtained from natural sources of different parts of plants. Therefore, their use in pest management has been considered as a natural and effective alternative to chemical pesticides. In this research, eucalyptus and thyme plants were selected as plant sources to extract active and effective compounds, and plant extracts were extracted using 70% ethanol solvent, and the mortality rate of 3rd instar larvae of the cotton bollworm, (Helicoverpa armigera) was determined concentrations of ethanol extract formulation was determined in laboratory conditions. The results showed that different concentrations of eucalyptus and thyme ethanol extract formulations have a statistically significant difference in the mortality rate of 3rd instar larvae of the cotton bollworm during 24 hours (p≤0.05). In the study of the lethality of concentrations of 20% and 30% and 40% and 50% of the ethanol extracts of eucalyptus and thyme, the results indicated that the concentrations of 30% and 40% and 50% caused the highest losses to the 3rd instar larvae of the cotton bollworm H. armigera After 24 hours, they created 79.993% and 77.493% and 91.243%, respectively. While 20% concentration caused the lowest losses (57.500%). Therefore, the formulation of ethanol extract of eucalyptus has more toxicity for cotton bollworm pest.
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