Author：Jih-Zu Yu ^1*, Yaw-Jen Dong ², Pei-Chen Hsu ², and Wan-Hsiu Yang ²

¹ Associate Reseach Fellow, Applied Zoology Division, TARI, Wufeng, Taichung, Taiwan, ROC.
² Assistant Reseach Fellow, Applied Zoology Division, TARI, Wufeng, Taichung, Taiwan, ROC.

Abstrct：

    The lethal efficacy of 23 plant species seed oils and 11 plant essential oils against cotton aphis (Aphis gossypii Glover), spider mites Kanzawa (Tetranychus kanzawai Kishida), and two-sptted spider mites (T. urticae Koch) were preliminarily screened. Then, we further try to compare the control efficacy of 3 plant oils with differnt saturated fatty acid content, coconut oil, palm oil and rapeseed oil (94.1, 51.9 and 5.1%, respectively) against Tetranychus urtice. Results showed that the LC₅₀ of such 3 oils were 2.23, 2.59, and 3.36 mL/L at 72 h after treated, and the LC₉₀ were 10.62, 7.53, and 17.82 mL/L, respectively. It is suggested that the lethal effect may be related to the content of saturated fatty acids. Coconut oil and palm oil will be developed potentially. In addition, compare the control efficacy of 4 different brands of soybean oil against A. gossypii. Three famous brands (Tatong Enterprise Co., Ltd., Taiwan Sugar Company, Taishan Enterprise Co., Ltd.) and Sigma -R&D grade of Aldrich Co. included. When the surfactant is mixed with each brand oil at 0.25:1 (V/V), the aphid control effects were good, and there were not significant difference among the four brands. Soybean oil is also to be developed potentialiy. And the ratio of surfactants mixed with above potential oils at 0.25:1 (V/V) is considable. Based on above results, “Plant Oil Mixture” was prepared consequently. The Plant Oils Mixture can be used for prevention and treatment in the pest management system. In prevention stage, Plant Oils Mixture can be used for soaking seedlings before planting, and sprayed weekly after planting that by using its essential oil content to play a deterrent effect. According to the field monitoring results, pest management should enter the treatment stage that the application dosage and frequency of Plant Oils Mixtur must be strengthen if the pest populations reach control threhold. In the formulation of pest management strategies, the characteristics and limitations of the plant protect materials, and the ecology, habits, etc. of control targets shoule be considered. However, other effective materials should be widely recruied to make up for the possible shortcoming of individual combat if the control ability of the Plant Oils Mixtur is insufficient.

Keywords： Plant Oils Mixture, seedling soaked treatment, pest management strategy.

* Correspondence address, e-mail: zyu@tari.gov.tw

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