The most important factor influencing the growth and survival of mosquito larvae is temperature. As a result, changes in the surrounding temperature may have an effect on the chemicals' toxicity to mosquitoes. The goal of the current study was to determine how temperature affected Culex pipiens' reactions to Commiphora molmol resin, Mirazid, crystalline (CASA), and acetylsalicylic acid in pharmaceutical form (PASA). Bioassay tests were carried out on the 3rd instar larvae under laboratory conditions, and the LC50 of each compound was determined. The LC50 of the four compounds were used to study the temperature-toxicity relationship, while the LC50 of Mirazid and (PASA), as the most toxic compounds, were used for further biochemical studies. Results indicated that, Mirazid was the most toxic compound, with LC50 of 28.3 ppm followed by C. molmol resin with LC50 of 41.6 ppm while the CASA was the least toxic compound with LC50 of 799.7 ppm. The temperature has a considerable impact on Cx. pipiens larval susceptibility to the tested compounds. High temperature (36 ̊C) resulted in high mortality rate (72.88, 78.20, 58.8 and 62.12 % for of C. molmol resin, Mirazid, CASA and PASA, respectively. Moreover, there were significant changes in α- esterase, β–esterase and glutathione -S-transferase levels as well as the total protein content in the treated larvae due to the change in temperature. The efficacy of Mirazid and C. molmol resin under wide range of temperatures made these compounds suitable candidates for controlling Cx. pipiens. |
