A Laboratory Assessment of Two Local Strains of the Beauveria bassiana (Bals.) Vuill. against the Tetranychus urticae (Acari: Tetranychidae) and Their Potential as a Mycopesticide

Abstract

This study was conducted to assess highly pathogenic Beauveria bassiana isolates to be used in biocontrol and to determine their potentials as mycopesticide. For this purpose, two B. bassiana isolates, which were locally isolated from T. urticae, were chosen. Firstly, three suspensions were investigated at the degree of humidity of 65 ± 5% and 100% RH. Secondly, these strains were selected according to their tendency to mass production, tolerance to UV radiation, and capability of producing spore at the different temperatures. Finally, identification of the selected isolate was performed by using ITS rDNA analysis. Both tested fungal isolates were pathogenic to the T. urticae. Mycelial growths of isolate AT076 at 20°C and 30°C were found to be greater than isolate AT007. It was observed that isolate AT076 had more spore production with 1.61 × 107 spore/disc at 30°C and 44.33% germination after UV radiation for 15 min. The numbers of spores per 5 mm disk area for isolates AT076 and AT007 were found to be 1.2 × 106 and 1.0 × 106. These results show that isolate AT076 was more virulent and more UV-tolerant and had higher tendency to mass production compared to isolate AT007 against T. urticae. As a result of this study, isolate AT076 can be used in the biocontrol as mycopesticide.

Development of mycoinsecticide formulations with Beauveria bassiana and Metarhizium brunneum for the control of Orosanga japonica (Hemiptera: Ricaniidae)

“…In addition, solar UV radiation is perhaps the most harmful environmental factor affecting the viability of fungal spores (Moore, Bridge, Higgins, Bateman, & Prior, 1993). Ortucu and Algur (2017) also reported that there are sudden changes in both radial and spores production, especially in 30 and 60 min of UV-B application, as in our study. Oil-based formulations are reportedly able to significantly increase the tolerance of conidia to UV radiation, with improved germination of conidia, in comparison in traditional waterbased formulations (Alves, Bateman, Prior, & Leather, 1998).…”

“…However, the germination and growth rate are decreased or deteriorating rapidly over 30°C (Fransen, Winkelman, & Van Lenteren, 1987). Qazzaz, Al‐Masri, and Barakat (2015) and Ortucu and Algur (2017) reported that radial growth and spore production of five B . bassiana isolates at different temperatures started to decrease especially at 30°C.…”

“…Dimbi, Maniana, Luz, and Mueke (2004) determined that the optimum temperature range for M. anisopliae isolates was between 24 and 30 C. In general, the optimum temperature for the growth and germination of entomopathogenic fungi in vitro condition is 25 C. However, the germination and growth rate are decreased or deteriorating rapidly over 30 C (Fransen, Winkelman, & Van Lenteren, 1987). Qazzaz, Al-Masri, and Barakat (2015) and Ortucu and Algur (2017) reported that radial growth and spore production of five B. bassiana isolates at different temperatures started to decrease especially at 30 C. The radial growth of B. bassiana KTU-24 decreased significantly when the temperature exceeded 28 C (Table 3). Also, Kessler, Matzke, and Keller (2003) and Cheong (2015) showed that a temperature above 27-30 C inhibited mycelial growth and killed spores.…”

“Metabolomic diversity of local strains of Beauveria bassiana (Balsamo) Vuillemin and their efficacy against the cassava mite, Tetranychus truncatus Ehara (Acari: Tetranychidae)”

“…urticae , causing 63.31 percent mite mortality at a concentration of 0.3×10 8 conidia/mL [ 45 ]. In another study [ 46 ], found that the pathogenicity effects of the two different strains of B . bassiana on T .…”

“…63.31 percent mite mortality at a concentration of 0.3×10 8 conidia/mL [45]. In another study [46], found that the pathogenicity effects of the two different strains of B. bassiana on T. urticae were 24-60% on the third day, 62.7-88% on the fifth day, and 90.7-100% on the seventh day. According to [47], the percentage of T. urticae deaths ranged from 55 to 82%.…”