Jinhao Zhao,Minmin Liang,Zhongyan Wang,Yanyan Zhao,Jingli Cheng,Yongjun Du
Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) is one of the most important parasitic natural enemies of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in peach and pear orchards. The artificial rearing T. dendrolimi have been widely used in biological control programs in recent years. However, its actual parasitic effect on the pest in the field is less, so it is important to develop attractants to increase the parasitic efficiency of the parasitoids. T . dendrolimi can be easily attracted by semiochemicals derived from flowers, intact plants, herbivore-attacked plants, and insects in its orchard habitats. In this paper, 73 semiochemicals were evaluated as potential attractants at three concentrations (0.1 mg/mL, 1 mg/mL, and 10 mg/mL) to T . dendrolimi by Y-tube olfactometer bioassays and Electroantennogram (EAG) technology, and then the mixtures of active individual compounds were further tested and evaluated in the field. As a result, 17 individual compounds showed attractive bioactivity to T . dendrolimi . Interestingly, when methyl salicylate and benzaldehyde mixed with linalool oxide or cis -3-hexenyl caproate in a volume ratio of 10:3:3 respectively showed excellent attractant bioactivity for T . dendrolimi in the orchard field. Thus, introducing such parasitoid attractants in orchard habitat may improve the biological control effect to pests.
The egg parasitoids, Trichogramma spp, are recognized as efficient biological control agents against various lepidopteran pests in agriculture and forests. The immature stages of Trichogramma offspring develop within the host egg, exhibiting remarkable diminutiveness (approximately 0.5 mm in adult length). RNA-interference (RNAi) methodology has emerged as a crucial tool for elucidating gene functions in numerous organisms. However, manipulating RNAi in certain small parasitoid species, such as Trichogramma, has generally posed significant challenges. In this study, we present an efficient RNAi method in Trichogramma denrolimi. The outlined procedure encompasses the acquisition and isolation of individual T. dendrolimi specimens from host eggs, the design and synthesis of double-stranded RNA (dsRNA), the in vitro transplantation and cultivation of T. dendrolimi pupae, the micro-injection of dsRNA, and the subsequent assessment of target gene knockdown through RT-qPCR analysis. This study furnishes a comprehensive, visually detailed procedure for conducting RNAi experiments in T. dendrolimi, thereby enabling researchers to investigate the gene regulation in this species. Furthermore, this methodology is adaptable for RNAi studies or micro-injections in other Trichogramma species with minor adjustments, rendering it a valuable reference for conducting RNAi experiments in other endoparasitic species.
危险品化学品经营许可证（带存储）