Effects of tea saponin on growth and development, nutritional indicators, and hormone titers in diamondback moths feeding on different host plant species.
The diamondback moth (DBM) is an important worldwide pest. This insect has been studied for several decades; however, its control remains problematic. Numerous chemical insecticides have become ineffective and chemical residues constitute an important problem. In the present study, we determined the mortality of 3rd instar DBM larvae feeding on three different host plant species and exposed to various concentrations of tea saponin (TS). In addition, we evaluated growth and development parameters, nutritional indicators, and juvenile hormone (JH) and molting hormone (MH) titers in 2nd instar larvae exposed to LC20 and LC50 doses of TS. We found that treatment of DBM larvae with LC20 and LC50 doses of TS led to lower growth rates, decreased feed consumption, reduced frass production, lower pupal weights, reduced percentage pupation, slower adult emergence percentages, and diminished fecundity, but prolonged durations of the larval and pupal periods. The efficiency of conversion of ingested and digested food increased, but the approximate digestibility did not differ significantly between treatments and controls. JH and MH titers were higher after TS treatment; these increases varied according to the host species and TS concentration. Our results indicate that TS represents a potential new alternative insecticide based on its natural origin, low cost, and minimum environmental impact.
College of Plant Protection, Fujian Agriculture and Forestry University, 15 Shangxia Dian Road, Fuzhou 350002, China; Fishery College, Jimei University, 43 Yindou Road, Xiame 361021, China.
Hongjiao
H
Cai
College of Plant Protection, Fujian Agriculture and Forestry University, 15 Shangxia Dian Road, Fuzhou 350002, China.
Yan
Y
Bai
Institute of Plant Protection, Fujian Academy of Agricultural Sciences, 247 Wusi Road, Fuzhou 350003, China. Electronic address: weihui@faas.cn.
Hui
H
Wei
Institute of Plant Protection, Fujian Academy of Agricultural Sciences, 247 Wusi Road, Fuzhou 350003, China.
Shuo
S
Lin
Institute of Plant Protection, Fujian Academy of Agricultural Sciences, 247 Wusi Road, Fuzhou 350003, China.
Yixin
Y
Chen
Institute of Plant Protection, Fujian Academy of Agricultural Sciences, 247 Wusi Road, Fuzhou 350003, China.
Houjun
H
Tian
College of Plant Protection, Fujian Agriculture and Forestry University, 15 Shangxia Dian Road, Fuzhou 350002, China. Electronic address: guxiaojun1@163.com.
Xiaojun
X
Gu
Division of Entomology, Department of Zoology, School of Life Sciences, Bharathiar University, Coimbatore 641 046, Tamil Nadu, India.
Kadarkarai
K
Murugan
D000818:Animals; D007300:Insect Control / Q000379:methods; D007301:Insect Hormones / Q000502:physiology; D007814:Larva / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D009036:Moths / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D012503:Saponins / Q000494:pharmacology*; D013662:Tea / Q000737:chemistry*
D007301:Insect Hormones; D012503:Saponins; D013662:Tea
Diamondback moth; Growth development; Hormones; Nutritional indicators; Tea saponin