酢浆草和车轴草作为螟黄赤眼蜂田间蜜源植物的可行性分析

Feasibility of Trifolium repens and Oxalis corniculata as the nectar resource plant to Trichogramma chilonis

利用蜜源植物可以有效提高节肢动物天敌的生物防治效果,已被广泛应用于生产。在稻田田埂上种植蜜源植物(如芝麻)已经取得了较大成功,然而由于芝麻种植具有一定的局限性,有必要筛选一些其他容易被接受、可替代的蜜源植物。三叶草,包括车轴草Trifolium repens(白花三叶草)和酢浆草Oxalis corniculata(红花三叶草)都是多年生植物,花期长、易在田边栽培成活,是十分具有潜力的候选蜜源植物。在实验室考察了这2种三叶草花能否延长和提高鳞翅目害虫卵期天敌螟黄赤眼蜂(Trichogramma chilonis)寿命和寄生力,以及酢浆草花不同时间段花蜜含量及其花蜜成分,同时还观察了三叶草花的开闭情况。结果显示,酢浆草花能显著延长和提高螟黄赤眼蜂的寿命和寄生力,而车轴草花虽然也能延长和提高螟黄赤眼蜂寿命和寄生力,但和清水对照组相比差异不显著。车轴草花基本是全天开花,不闭合;酢浆草花白天开花,晚上20点之后基本全部闭合,中午至傍晚酢浆草花蜜含量最高。综上,酢浆草花蜜含量较高,可以显著提高寄生蜂的生态功能,同时酢浆草花仅在白天开放,不会作用于夜间活动的鳞翅目成虫,生态风险较低,是一种潜在的适合稻田系统的蜜源植物。

As an effective way to improve biological control,nectar resource plant has been widely used in agro-ecosystem. Our previous experiment proved that planting nectar resource plant（Sesamum indicum） around the rice paddy field had made a great success in enhancing biological control of rice insect pests. However,due to the cultivation limitations of S. indicum,it is necessary to screening more acceptable,alternative nectar resource plants for different rice growing regions. Clovers,including Trifolium repens with white flower and Oxalis corniculata with red flower,areperennial plants with long florescence and easy to cultivate around rice paddy fields,and are potential candidates as nectar resource plants. In present study,we surveyed whether these two kinds of clover could prolong longevity and improve fecundity of Trichogramma chilonis,the dominant egg parasitoid of Lepidoptera pests. We also analyzed the nectar content of O. corniculata flowers in different time and the nectar compositions. The results showed that O.corniculata could extend longevity and improve fecundity of T. chilonis significantly. T. repens could extend longevity and improve fecundity of T. chilonis,but there was no significant difference between T. repens-fed treatment and water-fed treatment. The test of nectar content showed that O. corniculata flowers had the highest nectar content from14：00 to 16：00. T. repens flowers were basically in bloom for 24 h,but O. corniculata flowers were only open in the daytime. After 20：00,O. corniculata flowers were all closed. O. corniculata flowers contained a mass of nectar content and could significantly improve parasitic wasp biological fitness. Furthermore,O. corniculata flowers were only blooming during the daytime,which indicated that O. corniculata does not benefit moths. In conclusion,O. corniculata could be utilized as a potential nectar resource plant in rice-based agroecosystem.