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Fertility life table parameters of different strains of Trichogramma spp. collected from eggs of the carob moth Ectomyelois ceratoniae

Authors


Seyed H. Goldansaz, Department of Plant Protection, University of Tehran, PO Box 3158711167, Karaj, Iran. Email: goldansz@ut.ac.ir

Abstract

Fertility life table parameters were assessed for five populations (strains) of two Trichogramma species, T. embryophagum Hartig and T. principium Sugonyaev & Sorokina, collected from eggs of the carob moth Ectomyelois ceratoniae (Zeller) in Iranian pomegranate orchards. Four combinations of two constant temperatures (25°C, 30°C) and two relative humidity levels (50% RH, 70% RH) were used. The overall intrinsic rate of natural increase (rm) was significantly decreased with decreased relative humidity but was uninfluenced by temperature. The highest and lowest rm values were observed in T. embryophagum from Qum (0.34 ± 0.004) and T. embryophagum from Varamin (0.13 ± 0.01), respectively. Two-way interaction analyses revealed that the strains had significantly different responses in their rm values at different temperatures and relative humidities. In general, rm values were significantly higher at 25°C and 70% RH than at 30°C and 50% RH. The Qum strain of T. embryophagum was the most promising candidate to be considered as a biocontrol agent against E. ceratoniae due to its high reproductive rate (0.27 ± 0.01) at conditions (30°C and 50% RH) similar to the actual climatic conditions in Iranian pomegranate orchards during the major part of the growing season.

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