Evaluation of Insecticidal Efficacy and Toxicity of Chloroform Extracts of Some Plants Against Adults of Red Flour Beetle Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) Under Loboratory Conditions

Abstract

This study was conducted in the laboratories of the Department of Zoology, Faculty of Science, Sebha University, to evaluate the insecticidal efficacy and toxicity  of chloroform extracts of six plant: Piper nigrum L. fruits , Piper rubra L. fruits,  Allium sativumL. fruits,  Acacia nilotica L. fruits, Artemisia absinthium L. leaves   and the aerial parts of the Zygophyllm album against adults of red flour beetle  Tribolium castaneum  under laboratory conditions during different exposure periods( 24 hours , 48 hours and 7 days). the results showed that all  plant  chloroform extracts used  in study had clear insecticidal efficacy in affecting the mortality rate of the treated across all different exposure periods. The chloroform extracts of P. nigrum L. fruits showed the highest insecticidal efficacy, followed by the extracts of  A. absinthium L. leaves,  then the extracts of  A. nilotica L. fruits and P. rubra L. fruits  , while the extracts of  A. sativum L. Fruits and the aerial parts of the Z. album were the least effective compared to the other extracts. The results  also indicated a strong positive correlation and the rise in the mortality ratr of treated adults for all extracts used, as well as between the length of the exposure periods and the extracts efficacy in affecting the mortality rates of the treated adults. This reflects the cumulative and gradual nature of the effect of the active compounds in these extracts over time. Furthermore, these extracts showed a clear toxic effect against the red flour beetle adults, represented by the calculated LC₅₀ and LC₉₀ values during the different exposure periods. The toxic efficacy of these extracts clearly differed depending on the type of extracts. The chloroform extracts of  P. nigrum L. fruits, A. absinthium L. leaves, and A.  nilotica fruits were  the most toxic, and the toxicity of these extracts increased  with longer exposure periods, as evidenced by the gradual decrease in LC₅₀ and LC₉₀ values after 48 ours and 7 days of treatment.