Abstract

In the field of pest control, alternative approaches have been recently encouraged to avoid or minimize the hazards of synthetic insecticides and introduce new effective and safer biocontrol agents. The use of entomopathogenic nematodes (EPNs) is a safe and eco-friendly alternative to the synthetic pesticides for the control of various insect pests in different habitats worldwide. The major objective of this review was to gain a better understanding of the interactions between the cellular immune defences of insects and the EPN/bacteria complex immunosuppressive activity. It summarized recent literature on the major mechanisms of insect cellular immune defenses, such as encapsulation, nodulation, phagocytosis and increasing mitotic division of certain hemocytes. This review, also, described various qualitative and quantitative characters of the cellular immune defences of insects against suppressive strategies of the EPN/symbiotic bacteria complex. In conclusion, although few of the invading EPNs can be encapsulated, nodulated, or/and phagocytosized by the insect host, the majority of invading EPN/symbiotic bacteria usually overcome these defences by different mechanisms ending in the insect death. Therefore, many insect pests may be successfully controlled by using the appropriate concentration of effective EPNs under suitable biotic and abiotic conditions.

Key words: Encapsulation, Haemocoel, Immunocytes, Larvae, Mitotic Division, Mortality, Nodulation, Phagocytosis, Pathogen, Pupa