Disturbing Effects of Botanicals on the Haemogram and Immune Parameters of Insects: Recent Progress of The Search for Effective Biopesticides

Abstract

The excessive and indiscriminate uses of synthetic insecticides usually lead to many problems of human health, environment and economics. Therefore, it is a prerequisite to search for safe alternatives among which plant extracts and products represent effective materials for pest control. The main goal of the present article was searching for new control materials of the insect pests via the disruptive effects of these materials on the haemogram and immune parameters. In this article, we discussed the drastic effects of botanicals on the major haemogram parameters including total hemocyte population, differential hemocytes counts, cytopathological deformities of hemocytes, haemolymph (blood) volume, mitotic index and heart activity. It focused, also, on the innate immune reactions (humoral and cellular) in insects and the serious impacts of botanicals on their mechanisms (phagocytosis, encapsulation, nodulation and melanization). As concluded in the current article, botanicals inhibit the immune capability, leading to the insects become susceptible to the action of pathogenic microorganisms and ultimately death. This can be appreciated as a new strategy for the effective control of insect pests. However, some points of future research had been provided. In addition, some field works should be conducted to realize the botanical potential of the haematological and immunological criteria for insect pest control.