小菜蛾对合成植物挥发物的活性反应

Electroantennogram responses of the diamondback moth, Plutella xylostella, to three plant volatiles and field trapping test

在室内检验了小菜蛾已交配和未交配雌、雄成虫对3种合成植物挥发物乙酸顺-3-己烯酯(Z-3-hexenylacetate,ACTE)、异硫氰酸丙烯酯(allylisothiocyanate,NCS)和顺-3-己烯醇(Z-3-hexen-1-ol,OH)的触角电位(EAG)反应。不同浓度(0.008μg/μL、0.08μg/μL、0.2μg/μL、0.8μg/μL、8μg/μL、20μg/μL和40μg/μL)实验表明,随着刺激化合物浓度的提高,小菜蛾反应活性增强。但小菜蛾的性别及其交配状态可能影响其对3种化合物的反应强度:不同性别及交配状态的小菜蛾对ACTE的反应差异不大;未交配雌、雄虫对OH的反应强于已交配雌、雄虫;未交配雌虫对低浓度的NCS反应较强,NCS超过一定浓度时已交配雌虫的反应强于未交配雌虫,雄虫对NCS反应较小且与交配状态无关。以小菜蛾性信息素作为对照,在湖北长阳和越南河内试验了这3种植物挥发物诱芯(6μL/诱芯)对小菜蛾的引诱作用。结果表明,在湖北,第1天时ACTE、NCS对雄虫具有很强的引诱作用,引诱量显著大于性诱剂的引诱量,但随着诱芯放置时间延长,NCS引诱作用迅速下降,第2天时引诱作用已经很小;ACTE的引诱作用下降缓慢,第4天的诱蛾量才显著小于性信息素的诱蛾量,OH的引诱力较弱。在河内,ACTE、NCS、OH第1天对小菜蛾引诱作用很强,引诱量大于性信息素,但差异不显著;随着诱芯放置时间延长,3种挥发物对小菜蛾的引诱量均下降很快,第4天的引诱力就很弱。3种植物挥发物的混合物(体积比1∶1∶1)对小菜蛾的引诱作用与性信息素相似,且诱蛾活性持效期相对较长。无论在越南或湖北,植物挥发物或其混合物均很少引诱到雌虫。

Electroantennogram （EAG） responses of the diamondback moth （DBM）, Plutella xylostella to three plant volatiles, i.e. Z-3-hexen-l-ol （OH）, Z-3-hexenyl acetate （ACTE） and allyl isothiocyanate （NCS）, were tested in the laboratory. Tested with the volatiles at different concentrations of 0.008, 0.08μg／μL, 0.2 μg／μL, 0.8 μg／μL, 8μg／μL, 20μg／μL and 40μg／μL, DBM male or female had stronger responses to volatiles with higher concentration.Among the three volatiles, DBM had stronger response to NCS and ACTE. Responses to volatiles were different in male or female and in DBM mated or not. Field tests about captures by the three volatiles with 6μL per lure were conducted in Hubei province, China and in the suburb of Hanoi, Vietnam. DBM males were more attracted by ACTE and NCS at the two places at the beginning of the test, but the number of moths attracted by volatiles decreased quickly with time. Mixture of the three volatiles as 1 ： 1 ： 1 in volume also had good attractive activity to the diamondback moth. Few females were attracted by the three plant volatiles or their mixture.