殺卵劑對柑桔葉蟎卵毒抆之比較

Abstract

比較5種殺卵劑：Amitraz, Clofentezine, Fenothiocarb, Hexythiazox及Tetradifon對柑桔葉蟎(Panonychus citri)的殺卵效果，以Hexythlazox最好，在0.01mg/ml的濃度之下殺卵效力可達95%，其次是Fenothiocarb可達67%，而Clofentezine對柑桔葉蟎卵並無太大的毒效。不同卵齡的柑桔葉蟎卵對上述五種殺卵劑的殺卵力影響很大。殺卵效果著重在卵齡96小時以內的葉瞞卵上，對超過96小時卵齡的卵毒效明顯降低。此種現象以Hexythiazox及Tetradifon表現的最明顯。經Hexythiazox 0.1及0.05 mg/ml兩種濃度處理過的柑桔葉蟎雌成蟎，在48小時以內產卵能力都會降低，處理後49至96小時則僅剩0.1 mg/ml的高濃度仍會使葉蟎減少產卵量。97小時之後，所用各種濃度都不再影響葉蟎的產卵量。被以Hexythiazox 0.1及0.05 mg/ml兩濃度處理過的雌成瞞所產出的卵在觀察時間（144小時）內幾乎全數未能孵化，而經0.01 mg/ml處理的雌成蝓所產的無效卵比例則隨著時間增加而遞降。Hexythiazox在田間防治柑桔葉蟎效果可維持40天以上，且對安平草蛉(Chrysopa boninensis)及臺灣草蛉(C. septempunctata)之LC 50值皆大於1 mg/ml，是極具選擇性的殺蟎劑。 Ovicidal activity of Amitraz, Clofentezine, Fenthiocarb, Hexythiazox, and Tetradifon for the citrus red spider mite, Panonychus citri, was evaluated in the laboratory. Hexythiazox and Fenothiocarb showed good results, at 0.01 mg/ml, 96% and 67% mortalities were obtained respectively. Little activity of those 5 ovicides, especially Hexythiazox and Tetradion, to the eggs older than 96 hours were recorded. The adult mites treated with 0.1 and 0.05 mg/mi of Hexythiazox reduced their fecundities in 48 hours. The females were treated with 0.1 mg/mi laid less eggs in 49-96 hours. Almost all of the eggs laid by females which were treated with higher rates (0.1 and 0.05 mg/ml) would not hatch in 144 hours. Sterilizing effect of 0.01 mg/ml of Hexythiazox on the female adult mite was reducing along with time. Hexythiazox lasted for up to 40 days, when applied to the citrus red spider mite, and had the LC50 to green lacewings (Chrysopa boninensis, and C. septempunctala) over 1 mg/ml. Therefore, Hexythiazox is recognized as a promising selective acaricide for the citrus red spider mite control.