| Semiochemicals(SC) of plants play an important role on the co-evolution between chemical defence of plants and behavior of phytophagous insects. SC could protect cruciferous vegetables, including different ways, repelling of insect pests away from the plant, deterring egg laying of adults, hamperring feeding of larvae, and insect death after feed toxicity. Temperature is an important environment factor in growth and development of plants which effecting could regulate the secondary metabolism of plants. We studied on the release of volatiles of cruciferous vegetable Brassica parachinensis Bariley and their impact on biological characteristics of Plutella xylostella Linnaeus to optimize integrated control of the pest in the view of warming-up of the global climate.The result showed that the overall trend of volatile compounds increased in amount with the increase of temperature in intact and herbivored B. parachinensis except at 15℃. Plants damaged by diamondback moth larvae produced less volatiles in amount than the intact plants at all test temperatures between 15℃and 35℃, especially decreased significantly at 20℃and 25℃. The total amount of hydrocarbon, terpene, ester, alcohol and hydroxybenzene were all decreased significantly in herbivored plants at different temperatures, but only the percentages of hydrocarbon and ester were increased in herbivored plants. The aldehyde appeared only in herbivored plants at 35℃, but in control at all temperatures, with the content most at 25℃. The peak area and content of hydroxybenzene especially 2,6-bis(1,1-dimethylethyl)-4-methyl-phenol were obviously high in intact and herbivored leaves at 15℃, and all lower at other temperatures. The amount of 1,2-benzenedicarboxylic acid, bis (2-methylpropyl) ester was decreased significantly in herbivored plants at different temperatures, but the percentage was increased. The amount and percentage of terpene was increased significantly in herbivored plant at 30℃and decreased at other temperatures. It is reported that terpene had biological activity according to the literatures, and the result of our study showed that not only were the species of terpene fewer in intact and herbivored plants than hydrocarbon , but also the content was quite lower. Moreover, the changes of peak area and content of terpene presented no regularity.The numbers of male and female diamondback moth attracted to volatiles from herbivored plants were smaller than for the control. This result suggested that the nutrient change of herbivored plants showed a faint repellent effect on diamondback moth. From the repellent effect of moth herbivored plants, the susceptibility of female was attracted higher than male. The numbers of male and female Cotesia plutellae Kurdjumov attracted to herbivored plants were increased more significantly than for the intact plants, which suggested that the volatiles of herbivored plants showed a significant attractive effect on wasp. From the attractive effect of herbivored plants to wasp, the susceptibility of female wasp was higher to volatiles than for male wasp. The numbers of the control attracted to P. xylostella were most at 25℃. The numbers of herbivored plants attracted to C. plutellae were most at 30℃.This research helps to identify plant volatiles with biological activity, clarify the coevolution among plants, pests and natural enemies, and disclose the mechanisms of tritrophic interaction to develop a new strategy of integrated pest management in the circumstance of warm-up of global climate.
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