Effect of Application of UV Irradiated Beauveria bassiana and Metarhizium anisopliae on Larval Weight and Mortality of Spodoptera litura

Abstract

Entomopathogenic fungi have been widely used to control insect pests. The objective of this experiment was to find out the insecticidal activity of filtrate of entomopathogenic fungal cultures exposed to ultra violet (UV) C against the larvae of Spodoptera litura. The fungi used were Beauveria bassiana and Metarhizium anisopliae and their liquid cultures exposed to UV C (5, 10, 15, 20, and 30 watts) for 6 hours. The results showed that the larva mortality caused by B. bassiana culture filtrate without irradiation was the highest (97.3%) and significantly different from those caused by M. anisopliae culture filtrate (96.0%). However, the mortality caused by B. bassiana culture filtrate irradiated with UV C decreased significantly compared to the mortality caused by M. anisopliae culture filtrate irradiated by UV C. LT 50 of the filtrate of M. anisopliae culture irradiated with UV C was 10.51 days and was significantly shorter than those of B. bassiana (18.09 days). Thus, the M. anisopliae was more resistant to irradiation compared to B. bassiana.

Review: The effect and possible mitigation of UV radiation on baculoviruses as bioinsecticides

“…UV radiation is also a challenge to other biological control agents such as EPFs and Bt. The mortality of Spodoptera litura decreased significantly when exposed to Beauveria bassiana irradiated under UV-C (Herlinda et al 2020). Beauveria bassiana was unable to adjust to direct sunlight, and its conidia were swiftly destroyed by ultraviolet (UV) radiation (Jackson et al 2010;Kaiser et al 2019).…”