exploitation of endemic extremophilic microbial strains isolated from date palm fibrillium in the saoura region (southwest algeria) as potential biocontrol agents against mosquitoes

Background: algeria's extreme ecosystems, such as the saoura region, represent unique reservoirs of rare microor­ganisms, inhabiting pristine and unexplored virgin territories with considerable biotechnological potential. chi­tinolytic bacteria are particularly noteworthy for mosquito control due to their ability to degrade chitin, the major structural com­ponent of the insect cuticle. this study aims to: (i) identify new microbial strains adapted to extreme desert conditions, overcoming the limited efficacy of some bioinsecticides, (ii) address the spread of vector-borne diseases and mosquito resistance, (iii) reduce the environmental impacts of non-selective insecticides, and (iv) ex­plore eco-friendly strategies and integrated biological control.methods: shrimp chitin was extracted to prepare selective media for the isolation and purification of chitinolytic bacte­ria. the entomopathogenic activity of these chitinolytic strains at concentrations of 10⁴, 10⁵ and 10⁶ cfu/ml was eval­uated through bioassays on culex pipiens larvae.results: we isolated three chitinolytic strains from phoenix dactylifera bark, among which streptomyces spp. 2 (str2) was clearly the most virulent against cx. pipiens larvae. this strain exhibited marked dose and time-dependent toxicity (lc50-lc99: 7.9×10³-3.4×10⁷ cfu/ml; dc: 6.8×10⁷ cfu/ml; lt50: 4.6 days). beyond larval mortality, it also severely affected adults by reducing the proportion of flight-capable mosquitoes and increasing rates of flightlessness, post-emergence mortality, and deformity. however, an igr-like mode of action remains speculative. conclusion: this study confirms the larvicidal activity of desert-adapted chitinolytic bacteria, but further research is needed to determine their selectivity toward non-target organisms before considering their application in mosquito man­agement.