農藥對柑橘葉蟎、安平草蛉及黑卵蜂之毒性

Abstract

以柑橘園常用之14種殺蟲，殺蝓及殺菌劑測定其對柑橘葉蠟(Panonychus citri)，安平草蛉(Chrysopa baninensis)及草蛤卵寄生天敵--黑卵蜂(Telenomus ampullaceus)之毒性Benomyl, Dithianon, Mancozeb DDC-Ni等殺菌劑對葉蟲，草蛉及黑卵蜂之LC 50值皆大於1000 µg ai/ml，並沒有直接致死影響。其餘供試藥劑對柑橘葉蠟之毒性大小依序為Fenpropathrin>Cyhalothrin > Cyclohexatin > Bifenthrin>Benfuracarb>Carbosulfan>Dimethoate>Omethoate及Malathion。最後兩種藥劑之LC 50值超過1000 µg ai/ml。除Cyc10hexatin外，藥劑間對安平草蛉之毒性差距不大，LC5值最低5.0，最高31.0 µg ai/ml。 Cyclohexatin具有較佳的選擇性，對葉蟎、草蛉二者之LC 50比值大於36.9。但無法抑制黑卵蜂的羽化。抑制黑卵蜂的弱化能力以Bifenthrin, Cyhalothrin及Fenpropathrin較佳。以此三種藥劑之10與100 µg ai/ml的濃度處理草蛉卵，只能分別使36.0至63.3%，33.5至67.0及14.7至53.7%之卵免受黑卵蜂寄生。然而在此兩濃度之下，却分別能使64.0至97.8%，64.8至100%及26,6至96.0%的安平草蛉卵未能孵化。 Relative toxicities of 14 pesticides recommended for the control of citrus pests were tested against the citrus red spider mite, Panonychus citri, green lacewing, Chrysopa boninensis, and egg parasitoid of chrysopid, Telenomus ampidlaceus. The acute toxicities of fungicides (Benomyl, Dithianon, Mancozeb and DDC-Ni) to the tested species were not observed. Except these fungicides, the order of toxicity to citrus red spider mite was Fenpiropathrin>Cyclohexatin >Bifenthrin> Benturacarb > Carbosulfan> Dimethoate>Ornethoate, Malathion. LC50 of Omethoate and Malathion were over 1000 µg ai/ml. Cyclohexatin, an organotin compound, was a good selective acaricides with the highest ratio (36.9) of LC50 phytophagous mite / LC50 chrysopid, but it could not inhibit the emergence of egg parasitoid. Although organophosphates (Dimethoate, Omethoate, Malation) and carbamates (Methomyl, Benfuracarb and CarbosuLfan) were less toxic to the citrus red spider mite than pyrethroids (Bifenthrin, Cyhalothrin, Fenpropathrin), the toxicities of these insecticides to green lacewing were close to those of pyrethroids, the value of LC50 were all between 5.0 and 31.0 g ai/ml. Bifenthrin, Cyhalothin and Fenpropathriti seriously affected the emergence of parasitoid than other pesticides. When chrysopid eggs treated with 10 and 100 pg al/mi of these three pyrethoids, its parasitism was inhibited by 36.0 to 63,3%, 33.5 to 67.0% and 14.7 to 53.7%, respectively. But chrysopid eggs treated with these three chemicals at the concentration of 100 µg ai/ml almost all of the eggs were not hatched.