Acaricidal activity against Panonychus citri of a ginkgolic acid from the external seed coat of Ginkgo biloba.
An acaricidal substance extracted from the external seed coat of Ginkgo biloba L. was identified by UV (ultraviolet), IR (infrared), EI-MS (electron impact ion source mass spectrometry), (1)H NMR (nuclear magnetic resonance) and (13)C NMR as 6-[(Z)-10-heptadecenyl]-2-hydroxybenzoic acid (compound 1). Laboratory bioassay on citrus red mite, Panonychus citri (Mcg), showed that compound 1 possessed the following properties. (i) Powerful contact toxicity with an LC(50) of 5.2 mg litre(-1) after 24 h that was similar to that of pyridaben (LC(50) = 3.4 mg litre(-1)) and significantly superior to that of omethoate (LC(50) = 122 mg litre(-1)). Furthermore, its LC(90) was 13.4 mg litre(-1) after 24 h, which is significantly superior to both pyridaben (LC(90) = 69.6 mg litre(-1)) and omethoate (LC(90) = 453 mg litre(-1)). (ii) Quick-acting acaricidal activity. At identical concentrations, compound 1 was much faster-acting than pyridaben or omethoate. (iii) Compound 1 had strong corrosive action on the cuticle of P. citri but no phytotoxicity to plants.
Pan
Weigao
W
National Laboratory of Biocontrol Engineering of Grassland Pests, College of Life Science, Sichuan University, Chengdu 610064, China.
Luo
Peng
P
Fu
Ruobin
R
Gao
Ping
P
Long
Zhangfu
Z
Xu
Feiyi
F
Xiao
Haibo
H
Liu
Shigui
S
D000818:Animals; D002957:Citrus / Q000469:parasitology; D020441:Ginkgo biloba / Q000737:chemistry*; D007306:Insecticides / Q000737:chemistry / Q000302:isolation & purification*; D008925:Mites; D015394:Molecular Structure; D012459:Salicylates / Q000737:chemistry / Q000302:isolation & purification*
C510492:6-(10-heptadecenyl)-2-hydroxybenzoic acid; D007306:Insecticides; D012459:Salicylates