Evaluation of Volatile Organic Compounds from Broccoli Plants Infested with Myzus persicae and Parasitoids Aphidius colemani Attraction

Abstract

Volatile organic compounds (VOCs) from uninfested and infested broccoli plant samples with green peach aphid Myzus persicae were investigated by headspace solid microextraction (HS-SPME) combined with gas chromatography mass spectrometry (GC-MS). Overall, 25 compounds were identified in uninfested and infested broccoli plants. The HS-SPME combined with GC-MS analysis of the volatiles described the differences between the infested and uninfested broccoli plant samples. Based on peak area from the GC-MS analysis, the VOCs from infested broccoli were significantly greater than that from uninfested broccoli, such as D-limonene, Undecane, 3,4-dimethyl-, Heptane, alpha-Pinene, Oxalic acid, Citronellol, Tridecane, n-Decanoic acid, Cyclopentane, pentyl- and n-Hexadecanoic acid compared with volatiles released from uninfested broccoli. The results of Y-tube olfactometer showed that Myzus persicae were significantly attracted by the VOCs released from infested broccoli plants, more than uninfested plants or clean air. The percentage of aphid choice was 70% towards infested broccoli, and 10% were attracted to the clean air choice and uninfested plants. With the comparison between clean air and uninfested plants, the aphids were attracted by 84% for broccoli, while 7% were attracted towards clean air. Comparing between infested and uninfested, the aphid attracted by 26.6% for infested broccoli, versus 30% for uninfested broccoli. The preferences of Aphidus colemani to the infested, uninfested plants with M. persicae and compared with clean air were measured. The results indicated that parasitoids could discriminate the infested broccoli and significantly respond to the plant odour and attractive by 100% for the parasitoid towards infested broccoli plants.