Iraqi Journal of Veterinary Sciences

Abstract

The current work on mosquito larvae was performed to evaluate the resistance status of larvae to deltamethrin (DM) and to detect if the larvicidal activity (LA) of this chemical could be synergized after exposing the larvae to cinnamaldehyde (CD). Here, 200 Aedes albopictus larvae were employed for the experiment and were divided randomly into 2 groups (100/each group and placed in petri-dishes (PD), 10 larvae/PD), and they are the DM group (1ml of 0.04 mg/l in 99ml of distilled water (DW) was placed to each PD) and the DM+CD group (1ml of 0.04 mg/l and 1ml of 0.9mg/l respectively were placed with 98ml DW in each PD). The experiment was lasted for 24hrs. Larvae were detected to have resistance against DM as 45% to 60% of the larvae were killed by the DM, 40% to 55% resistance rate. However, when evaluating DM activity with the use of CD, the LA was synergized showing mortality in 87% to 92% of the larvae in which a significant (p<0.05) increase in the mortality in DM+CD group was noticed more than that in the DM group. Furthermore, RT-qPCR was run to identify the expression status of the P540 monooxygenase gene, Cyp6p15, and found that the gene expression was significantly (p<0.05)

inhibited in the DM+CD group when comparing that in the DM group that showed overexpression of this gene. This work results provide viable information about the potential activity of the cinnamaldehyde in synergizing the larvicidal activity of deltamethrin.