Toxicity of Lavandula angustifolia oil constituents and spray formulations to insecticide-susceptible and pyrethroid-resistant Plutella xylostella and its endoparasitoid Cotesia glomerata.
BACKGROUND
Plutella xylostella is one of the most serious insect pests of cruciferous crops. This study was conducted to determine the toxicity of 21 constituents from Lavandula angustifolia essential oil (LA-EO) and another 16 previously known LA-EO constituents and the toxicity of six experimental spray formulations containing the oil (1-6 g L(-1) sprays) to susceptible KS-PX and pyrethroid-resistant JJ-PX P. xylostella larvae, as well as to its endoparasitoid Cotesia glomerata adults.


RESULTS
Linalool and linalool oxide (LC50 = 0.016 mg cm(-3) ) were the most toxic fumigant compounds and were 10.7-fold less toxic than dichlorvos to KS-PX larvae. Either residual or fumigant toxicity of these compounds was almost identical against larvae from either of the two strains. Against C. glomerata, dichlorvos (LC50 = 7 × 10(-6)  mg cm(-3) ) was the most toxic insecticide. LA-EO was ∼1430 times less toxic than dichlorvos. The oil applied as 6 g L(-1) spray and emamectin benzoate 21.5 g L(-1) emulsifiable concentrate provided 100% mortality against larvae from either of the two strains.


CONCLUSIONS
Reasonable P. xylostella control in greenhouses can be achieved by a spray formulation containing the 6 g L(-1) oil as potential contact-action fumigant. © 2015 Society of Chemical Industry.
Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.
Chang Geun
CG
Yi
Department of Plant Biotechnology and Biotransformation, Faculty of Biology, Ho Chi Minh City University of Science, Vietnam National University, Ho Chi Minh, Vietnam.
Tran Trung
TT
Hieu
Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.
Si Hyeock
SH
Lee
Crop Protection Division, Department of Crop Life Safety, National Academy of Agricultural Science, Rural Development Administration, Jeonju, South Korea.
Byeoung-Ryeol
BR
Choi
Highland Agriculture Research Institute, National Institute of Crop Science, Rural Development Administration, Pyeongchang, South Korea.
Min
M
Kwon
Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea.
Young-Joon
YJ
Ahn
D000336:Aerosols; D000818:Animals; D004006:Dichlorvos; D007300:Insect Control / Q000379:methods; D007305:Insecticide Resistance; D007306:Insecticides / Q000008:administration & dosage / Q000494:pharmacology*; D007559:Ivermectin / Q000031:analogs & derivatives; D027523:Lavandula / Q000737:chemistry*; D009036:Moths / Q000469:parasitology; D010938:Plant Oils / Q000008:administration & dosage / Q000494:pharmacology*; D014863:Wasps / Q000187:drug effects / Q000502:physiology
D000336:Aerosols; D007306:Insecticides; D010938:Plant Oils; D007559:Ivermectin; D004006:Dichlorvos; C108024:emamectin benzoate
Cotesia glomerata; Lavandula angustifolia oil; Plutella xylostella; botanical insecticide; natural fumigant; pyrethroid resistance