BIOINSECTICIDE ACTIVITY OF SILVER NANOPARTICLES PRODUCT OF BIOSYNTHESIS USING ENTOMOPATHOGEN AGAINST THE BEET CATERPILLAR SPODOPTERA EXIGUA

Abstract

Spodoptera exigua (Hubner) is a polyphagous insect pest that is detrimental to farmers. Nanotechnology exists as a renewable technology that can increase effectiveness due to the small size of particles it produces. This study aimed to determine the effectiveness of biosynthesis of silver nanoparticles from the fungi Metarhizium, Trichoderma, and The Bacillus bacteria which are biocontrol agents. The research started in February and ended in May 2020, at the Biological Research Laboratory, Faculty of Mathematics and Natural Sciences Education, University of Pendidikan Indonesia. The experiment was based on a completely randomized design method (CRD). Onion armyworm (Spodoptera exigua), two isolates from the fungi Metarhizium and Trichoderma were obtained from the Indonesia Vegetable Research Institute (IVERRI). Each extract of Metarhizium and Trichoderma fungi and 50 mL of extract from Bacillus bacteria were added to 50 mL of Ag + 60 ppm solution in a 250 mL glass tube. The mixture of Metarhizium mushroom extract with 60 ppm Ag + solution or Trichoderma mushroom with Ag + 60 ppm solution was incubated at 400 C with a rotation speed of 200 rpm for five days under a dark condition. For the mixture of bacterial extracts with Ag + 60 ppm solution, incubation was at room temperature with a rotation speed of 150 rpm for three days. Analysis of the effect of NPP on the mortality of S. exiguawas done using the treatments, Metarhizum, Trichoderma, Bacillus, NPP-Metarhizium, NPP-Trichoderma, NPP-Bacillus, NPP, and distilled water as controls. Third instar larvae of S. exigua were immersed for 30 seconds. After immersion, the larvae are placed in sterile Petri dishes that have been lined with sterile filter paper and provided with caterpillar feed. Observation of caterpillar mortality was recorded at 2, 4, 6, 9, 24, 48, 64, 72, 96 and 108 hours after treatment. There were three replicates the results showed that all the treatments caused death of the insect, both entomopathogens and entomopathogenic nanoparticles. We found the three treatments of silver nanoparticles highly lethal to S. exigua. Two treatments, NPP-Metarhizium and NPP-Bacillus even caused 100% mortality after 120 hrs treatment. The possible reason for the pathogenicity of these products is considered to be biosynthesis of nanoparticles and enzymatic substances