BIOLOGICALSTUDIES AND COLD STORAGE OF EGGPARASITOIDS Trichogramma evanescensWESTWOOD AND Trichogramma euproctidisGIRAULT (HYMENOPTERA:TRICHOGRAMMATIDAE)

Abstract

A biological study was conducted to determine optimal temperature for mass rearing of two species of Trichogramma; Trichogramma euproctidis and T. evanescens. Three temperatures (20, 25 and 30 ͦ C) were tested. Obtained results showed that 30 ͦ C was the most favorable temperature to give highest parasitism for T. euproctidis (250.6 eggs) and T. evanescens (124.5 eggs) followed by 25 ͦ C then 20 ͦ C. The impact of the inoculation dosages (1 Inoculum/3, 4, 6, 8 and 10 Host surfaces Ephestia kuehniella on their rate of parasitism was studied. results showed that mass rearing of Trichogramma can be done on E. kuehniella eggs up to the dosages of 1/10 (1/HS), also at all treatment the parasitism rate was higher for T. evanescens than for T. euproctidis.

A study was carried out to assess the suitable storage temperature and duration for T. euproctidis and T. evanescens. The effect of storage of the two parasitoids on intermediate degrees (4, 8, 12 and 15 days) then stored at 3 ͦ C for different periods was studied. Highest mean number of parasitism (113.9 and 86.5 egg) for T. euproctidisand T. evanescens recorded at 3 ͦ C for 60 days storage after keeping for 15 days at 15 ͦ C as intermediate temperature. Results obtained from this study indicated that 12 ͦ C and 15 ͦ C was the most effective temperature for storage of T. euproctidis and T. evanescens For both long and short term storage.

Finally, Assessment of T. euprocitidis,for the control of Tuta absoluta in tomato greenhouses, three release doses (25, 50 and 75 parasitoids/m²) were tested during two year experiment 2011/12 and 2012/13 at Berkash(Giza). The results show that T. euproctidis was significantly efficient, especially at a higher dose, in keeping down T. absoluta mines during both experimentation years.