Comparison between two methods of mycelia growth evaluation of some Oomycetes species

  • Najwa Benfradj Department of Biological Sciences and Plant Protection, High Institute of Agronomy of Chott Mariem, University of Sousse, 4042 Sousse, Tunisia
  • Amai Rouini Department of Biological Sciences and Plant Protection, High Institute of Agronomy of Chott Mariem, University of Sousse, 4042 Sousse, Tunisia
  • Naima Boughalleb-M’Hamdi Department of Biological Sciences and Plant Protection, High Institute of Agronomy of Chott Mariem, University of Sousse, 4042 Sousse, Tunisia
Keywords: calculated area, measured area, growth factors, mefenoxam, ratio


Oomycetes pathogens causes devastating crop diseases worldwide. In this study, we compared mycelium growth of 7 Oomycetes species using the calculated area (CA) method obtained by perpendicular diameter of colony and measured area (MA) method. Results revealed a significant difference between Oomycetes species inhibition ratio using CA and MA, at lower mefenoxam concentrations. The interval of variation between MA/CA methods was variable according to Oomycetes specie. The largest interval (0.01-1000 μg/ml) was detected with Pythium aphanidermatum and Phytopythium mercuriale. The second interval (0.01-100 μg/ml) was determined by Phytophthora cryptogea, P. aphanidermatum, P. ultimum and P. mercuriale. An interval ranged from 0.01μg/ml to 31.6μg/ml was recorded with P. cryptogea and Phytopythium vexans. An interval from 0.01 μg/ml to 10μg/ml was determined with Pythium dissotocum and P. vexans; while the shortest interval (0.01-1μg/ml) was noted with P. nicotianae. In addition, present findings recorded a difference in Pearson’s correlation index between growth factors (medium, evaluation dates, mefenoxam concentration) and Oomycetes mycelium growth using MA and CA methods. A statistical significance difference (P<0.05), weas noted more in case MA method and was more expressed in case of CA method.


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How to Cite
Benfradj, N., Rouini, A., & Boughalleb-M’Hamdi, N. (2022). Comparison between two methods of mycelia growth evaluation of some Oomycetes species. Journal of Phytopathology and Pest Management, 9(1), 1-13. Retrieved from
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