Pathogenicity and Toxicity of Entomopathogenic Nematodes Isolated from Egypt on Spodoptera littoralis and Agrotis ipsilon

Document Type : Original Article

Authors

1 Plant Protection Research Institute, ARC, Dokki, Giza- Egypt.

2 Entomology Department -Faculty of Science, Cairo University, Giza- Egypt.

3 Chemistry Department -Faculty of Science, Cairo University, Giza- Egypt.

Abstract

This study was managed to isolate and identify entomopathogenic nematodes from Egypt. In addition, the pathogenicity and toxicity of these isolated nematodes on Spodoptera littoralis and Agrotis ipsilon larvae were declared. Also, hemolymph protein patterns of uninfected and infected larvae of S. littoralis and/or A. ipsilon were screened. Results declare that EPNs were extracted from soil samples of Egyptian mango trees in Ismailia, Governorate, only 2% of soil samples were positive for the nematode Heterorhabditis which was confirmed by the morphological signs of dead Galleria larvae which turned dark-red colour and recorded the bioluminescence phenomena in the dark. Also, all tested Heterorhabditis strains induce a positive influence on larval mortality while a negative influence on pupation and adult emergence against both insects Spodoptera littoralis and A. ipsilon. After infection of S. littoralis 5th larval instar, LC50 values were 33.51, 45.30, 73.24 and 39.11 IJs/Larvae, for Heterorhabditis bacteriophora HP88, Heterorhabditis indica AZ1, Heterorhabditis indica AZ2 and Heterorhabditis sp. HS, respectively. After infection of A. ipsilon 5th Larval instar, LC50 values were 76.64, 82.58, 135.95 and 68.44 IJs/Larvae, at the previous arrangement for nematodes. From the previous results, the native isolates H. sp. HS was more pathogenic against tested insects than others. In addition, Spodoptera littoralis larvae were found to be more susceptible to all Heterorhabditis strains than A. ipsilon larvae. In addition, in both tested insects Spodoptera littoralis and A. ipsilon, larvae infected with the sub-lethal concentration LC50 showed a significant genetic variation in their protein pattern compared to control samples. The results declared that there is a protein band characteristic of all Heterorhabditis nematodes with M.W. 35KDa that may be defined as a toxic protein. From the above results, it can be concluded that the isolated strains of Heterorhabditis will be a promising agent in integrated pest management (IPM) Programs.

Keywords

Files

Share

How to cite

Statistics