Acarological Society of Iran Persian Journal of Acarology 2251-8169 11 1 2025 12 01 Toxicity and ovicidal activity of different entomopathogenic fungi, Hirsutella extracts on Tetranychus urticae(Acari:Tetranychidae) 133 143 238568 10.22073/pja.v11i1.70229 EN Suradet Buttachon Department of Entomology, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University War War May Zin Department of Chemistry, Pathein University, Pathien 10014, Myanmar Journal Article Crude ethyl acetate extracts of six entomopathogenic fungi, <em>Hirsutella</em> species were screened against <em>Tetranychus urticae</em> Koch (Acari: Tetranychidae). In this study, all extracts presented potential to control eggs and adult female activities. Laboratory evaluation of the crude extracts of <em>Hirsutella citriformis</em>,<em> H. guignardii</em>,<em> H. petchabunensis</em>,<em> H. satumaensis</em>, <em>H. saussurei</em> and <em>H. thompsonii</em> showed slightly toxicity and median lethal concentration (LC₅₀) values of 7,579.94, 8,910.38, 8,579.45, 5,055.96, 1,555.46 and 44,197.85 mg/L at 72 h after treatment against adult females of <em>T. urticae</em>, respectively. Related LC₅₀ values that exhibited on eggs were 12,701.86, 30,922.72, 10,870.96, 12,635.56, 9,244.59 and 22,676.66 mg/L at 5 days after exposure. The most effective on <em>T. urticae</em> eggs and adult females is <em>H. saussurei</em>. Moreover, all extracts deceased the fecundity of <em>T. urticae</em> after being fed with mulberry leaf discs treated the crude extract of six species of <em>Hirsutella </em>under residual effect bioassay. The results suggest that the ethyl acetate extracts of <em>Hirsutella citriformis</em>,<em> H. guignardii</em>,<em> H. petchabunensis</em>,<em> H. thompsonii</em>, <em>H. satumaensi </em>and<em> H. saussurei</em> have the potential to be used for the control of <em>T. urticae</em> in the future. https://www.persianacarology.org/article_238568_b824344fd1076d60f3b4f985e32d4b2c.pdf