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Title Isolation and identification of entomopathogenic nematodes from selected areas in Lanao del Norte, Philippines and their infectivity against Zophobas morio (Coleoptera:Tenebrionidae)
Posted by Nanette Hope Sumaya
Authors Leonar, A.L.C and Sumaya, N.H.N
Publication date 2019/11/18
Conference Entomological Society of America Annual Meeting Entomology 2019
Publisher ESA
Abstract The increasing need to reduce synthetic pesticide applications has driven the interest in utilizing entomopathogenic nematodes (EPNs) as biocontrol agents against agricultural pests. Unlike the former, EPNs are non-polluting, non-toxic and safe for the environment and the user. The vast diversity of naturally-occurring EPN populations in the Philippines may unravel local or native isolates with higher efficacy against target pests. Native isolates are continuously being identified due to their adaptability to host insects, local climate and environmental conditions. In this study, EPN occurrence was surveyed in coastal grassland, agricultural and forest ecosystems in selected areas of Lanao Del Norte, Philippines. Insect-baiting technique using the larvae of the superworm, Zophobas morio was done. From a total of 50 soil samples, only 14 samples from the coastal grassland areas with sandy soils and sufficient moisture levels were EPN-positive (28%). Based on morphological characterization and morphometrics, the 14 recovered EPN isolates were grouped into Heterorhabditidae and Rhabditidae families and further characterized. Molecular processing and sequencing of the internal transcribed spacer (ITS) region was used to identify and confirm EPN isolates to species level. EPNs identified were Heterorhabditis indica and Metarhabditis amsactae with the first report of M. amsactae in the Philippines. Using sand bioassays, the infectivity of H. indica (95%) and M. amsactae (58%) isolates against the larvae of Z. morio was assessed. On-going studies are conducted for their virulence against other insects like Galleria mellonella and Tenebrio molitor. The findings from this study may contribute to the biocontrol programs in the country.
Index terms / Keywords Biological control, DNA barcoding, Insect pests, Nematodes, Virulence