Abstract Perilla, Perilla frutescens (L.) Britton var. crispa (Thunb.) H. Deane, is traditionally cultivated as an edible/medicinal crop in East Asia. Its essential oil contains many bioactive compounds that are expected to have high pharmacological functionality, as well as antimicrobial and insecticidal activity. Spider mites are a major pest group for perilla cultivation. The two-spotted spider mite, Tetranychus urticae Koch, possesses divergent detoxification enzymes and has developed resistance against most acaricides. The essential oil content of perilla halves from the preflowering phase to the flowering phase, and ultraviolet (UV)-B radiation generally increases defense compounds. To clarify the effects of this change in essential oil content and the effects of UV-B pretreatment, we investigated the developmental success and egg production of T. urticae on leaves from the preflowering and flowering phases cultivated with and without nighttime UV-B irradiation. Both the parameters significantly increased on leaves from the flowering phase in comparison with that from the preflowering phase, suggesting that constitutively produced essential oil provided protection against mite pests in a growth phase-specific manner. The defense system also extended the developmental period of mites on red perilla leaves, but not on green perilla leaves, in preflowering phase. Although egg production was lower on red perilla leaves pretreated with UV-B, no negative effects were caused on the developmental success and duration on red and green perilla and the egg production on green perilla by UV-B pretreatment. Our findings reveal a significant impact of investment allocation of perilla plants and a small contribution of UV-B irradiation to the plant defense system.

中文翻译：

---

紫苏叶生长期和UV-B预处理对二斑叶螨的影响

Abstract Perilla, Perilla frutescens (L.) Britton var. crispa (Thunb.) H. Deane，在东亚传统上作为一种食用/药用作物种植。它的精油含有许多生物活性化合物，预计具有很高的药理功能，以及抗菌和杀虫活性。红蜘蛛是紫苏栽培的主要害虫群。二斑叶螨 Tetranychus urticae Koch 具有不同的解毒酶，并对大多数杀螨剂产生抗药性。从开花前期到开花期，紫苏的精油含量减半，紫外线 (UV)-B 辐射通常会增加防御化合物。为了阐明这种精油含量变化的影响和 UV-B 预处理的影响，我们研究了在有和没有夜间 UV-B 照射下栽培的开花前期和开花期叶子上的荨麻疹的发育成功和产卵量。与开花前期相比，开花期叶片的这两个参数都显着增加，这表明组成型生产的精油以特定生长阶段的方式提供了对螨类害虫的保护。在开花前期，防御系统还延长了红紫苏叶上螨虫的发育期，但没有延长绿紫苏叶上螨虫的发育期。尽管 UV-B 预处理的红紫苏叶产蛋量较低，但 UV-B 预处理对红紫苏和绿紫苏的发育成功率和持续时间以及绿紫苏的产蛋量没有造成负面影响。