1- Department of Plant Protection, Faculty of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran. , a.hatami0818@gmail.com
2- Department of Plant Protection, Faculty of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran.
3- Department of Plant Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Islamic Republic of Iran.
2- Department of Plant Protection, Faculty of Agriculture, University of Tabriz, Tabriz, Islamic Republic of Iran.
3- Department of Plant Sciences, Faculty of Natural Sciences, University of Tabriz, Tabriz, Islamic Republic of Iran.
Abstract: (888 Views)
Entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae are important and effective biocontrol agents against arthropod pests. Compared to chemical insecticides, insect pests do not easily develop resistance against these fungi. In this study, the lethal effects of exposure to B. bassiana and M. anisopliae, effects on phenol-oxidase activity, total haemocyte count, and changes in granulocytes and plasmatocytes were evaluated in 3rd instar larvae of Helicoverpa armigera. The LC50 values for B. bassiana and M. anisopliae were 0.795×106, and 5.972×107 spore mL-1, respectively. LC30 and LC10 of either entomopathogenic fungi were injected into the body of larvae, and 24 and 48 hours after injection, their hemolymph was extracted. After 24 hours, the highest and lowest phenol-oxidase activity was observed in LC30 of M. anisopliae, and LC10 of B. bassiana, respectively. After 48 hours of infection, phenol-oxidase activity increased in all treatments. At the LC30 of M. anisopliae, the highest phenol-oxidase activity was recorded, and other treatments also showed a significant difference compared to the control. Five types of hemocytes including prohemocytes, plasmatocytes, granulocytes, oenocytoids, and spherulocytes were identified in the hemolymph of larvae. The highest Total Hemocyte Count (THC) was recorded in LC30 M. anisopliae at 9 hours after initial infection. The highest number of granulocytes and plasmatocytes were recorded 9 hours after treatment in LC30 of M. anisopliae and LC30 of B. bassiana. Our results showed that both fungi had the ability to affect phenol-oxidase enzyme activity and haemocytes. These microbial insecticides exhibited high potential for controlling the pest.
Article Type: Original Research |
Subject:
Toxicology and Physiology
Received: 2023/10/28 | Accepted: 2024/01/1
Received: 2023/10/28 | Accepted: 2024/01/1
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