TY - JOUR
T1 - Survey of entomopathogenic nematodes and associate bacteria in Thailand and their potential to control Aedes aegypti
AU - Suwannaroj, Manawat
AU - Yimthin, Thatcha
AU - Fukruksa, Chamaiporn
AU - Muangpat, Paramaporn
AU - Yooyangket, Temsiri
AU - Tandhavanant, Sarunporn
AU - Thanwisai, Aunchalee
AU - Vitta, Apichat
N1 - Publisher Copyright:
© 2020 Blackwell Verlag GmbH
PY - 2020/4/1
Y1 - 2020/4/1
N2 - Aedes aegypti is an insect vector that transmits several viruses affecting humans worldwide. Entomopathogenic nematodes (EPNs) and their symbiotic bacteria are organisms with the potential to control many insects. In this study, we did a survey aimed to identify EPNs and their symbiotic bacteria and evaluate the larvicidal activity of bacteria against Ae. aegypti. We collected 540 soil samples from 108 sites in Phitsanulok Province, lower northern Thailand. Baiting techniques and White traps were used to isolate EPNs from soil samples. By sequencing of 28S rDNA and internal transcribed spacer regions, 51 EPN isolates were identified as Steinernema surkhetense (35 isolates), Heterorhabditis indica (14 isolates) and Heterorhabditis sp. SGmg3 (two isolates). Based on sequencing of a partial region of the recA gene, 35 isolates of Xenorhabdus were identified as Xenorhabdus stockiae, and 20 Photorhabdus isolates were identified as Photorhabdus luminescens subsp. akhurstii (10 isolates), P. luminescens subsp. hainanensis (seven isolates) and P. asymbiotica subsp. australis (three isolates). Screening for larvicidal activity of bacteria against Ae. aegypti was performed in the laboratory. Xenorhabdus WB5.4 and Xenorhabdus WB12.5, which were closely related to X. stockiae, resulted in high mortality of Ae. aegypti (99.99% and 70%, respectively) at 96 hr after exposure. Comparing with control groups, mortality of Ae. aegypti larvae was low (1.11%–6.67%) after exposure for 24–96 hr. Our findings showed the potential of X. stockiae for controlling Ae. aegypti. Further studies are needed to elucidate the mechanisms through which these bacteria kill Ae. aegypti larvae.
AB - Aedes aegypti is an insect vector that transmits several viruses affecting humans worldwide. Entomopathogenic nematodes (EPNs) and their symbiotic bacteria are organisms with the potential to control many insects. In this study, we did a survey aimed to identify EPNs and their symbiotic bacteria and evaluate the larvicidal activity of bacteria against Ae. aegypti. We collected 540 soil samples from 108 sites in Phitsanulok Province, lower northern Thailand. Baiting techniques and White traps were used to isolate EPNs from soil samples. By sequencing of 28S rDNA and internal transcribed spacer regions, 51 EPN isolates were identified as Steinernema surkhetense (35 isolates), Heterorhabditis indica (14 isolates) and Heterorhabditis sp. SGmg3 (two isolates). Based on sequencing of a partial region of the recA gene, 35 isolates of Xenorhabdus were identified as Xenorhabdus stockiae, and 20 Photorhabdus isolates were identified as Photorhabdus luminescens subsp. akhurstii (10 isolates), P. luminescens subsp. hainanensis (seven isolates) and P. asymbiotica subsp. australis (three isolates). Screening for larvicidal activity of bacteria against Ae. aegypti was performed in the laboratory. Xenorhabdus WB5.4 and Xenorhabdus WB12.5, which were closely related to X. stockiae, resulted in high mortality of Ae. aegypti (99.99% and 70%, respectively) at 96 hr after exposure. Comparing with control groups, mortality of Ae. aegypti larvae was low (1.11%–6.67%) after exposure for 24–96 hr. Our findings showed the potential of X. stockiae for controlling Ae. aegypti. Further studies are needed to elucidate the mechanisms through which these bacteria kill Ae. aegypti larvae.
KW - Heterorhabditis
KW - Steinernema
KW - biocontrol
KW - phylogeny
KW - symbiotic bacteria
UR - http://www.scopus.com/inward/record.url?scp=85077874411&partnerID=8YFLogxK
U2 - 10.1111/jen.12726
DO - 10.1111/jen.12726
M3 - Article
AN - SCOPUS:85077874411
SN - 0931-2048
VL - 144
SP - 212
EP - 223
JO - Journal of Applied Entomology
JF - Journal of Applied Entomology
IS - 3
ER -