(17(3):17-25)EFFECTIVENESS OF VARIOUS INSECTICIDES FOR DESTROYING ORINTAL FRUIT FLY, DACUS DORSALIS HENDEL, INFESTATIONS IN GREEN MATURE BANANA

（一） EDB. Nankor，sumithion，Lebaycid四種藥劑對青香蕉行滅蠅浸漬時，以EDB，Sumithion及Lebaycid之效果最佳，Nankor較差而不適宜於植物檢疫上之要求。將來外銷香蕉須行此項處理時，EDB最低濃度應為0.3ml/L浸漬5分鐘或0.5ml/L浸漬3分鐘，最高不得超過0.9ml/L以上。Sumithion與Lebaycid之實用度則為0.025%～0.05%浸漬30~60秒。 （二） 燻蒸處理不論以EDB或Phostoxin，在完全殺蟲之濃度範圍內，皆能引起藥害或催熟作用，故不適合於蕉果之商品處理（Commodity treatment）。 （三） 在實用濃度範圍內（有完全殺蟲而又不損及蕉果之濃度），經EDB浸漬處理後之青香蕉，無催熟現象發生，且經加工黃熟後，亦不改變外觀或味覺。 （四） Sumithion與Lebaycid之機械噴藥，在較短時間內處理時，効果較浸漬處理為差。不過若噴藥時間延長至60秒以上，即使在較低之0.025%濃度內，也可殺死蕉果內全部之果蠅卵及幼蟲。至於噴藥前之沖水洗滌與否，對殺蟲劾果並無影響。 The purpose of this study was to clarify the effect of five insecticides to destroy the oriental fruit fly, Dacus dorsalis Hendel, infestation in green mature banana, and to see if its effect can meet the requirements of plant quarantine, The insecticides used in this experimentation are E D B (Ethylene dibromide), Nankor, Sumithion, Lebaycid and Phostoxin. The phytotoxicity of some insecticides on green banana also were made. Results obtained from this study are summarized as follows: 1. In comparison with the effectiveness of E D B, Nankor, Sumithion and Lebaycid water dipping, EDB, Sumithion and Lebaycid gave an excellent effect on the killing of fly eggs and larvae hidden in banana fruit. However, Nankor gave less effectiveness and thus Nankor is not suitable for export banana treatment. The data shown below are to be referred in the event when such treatment is required for export babana. EBD: Minimum concentration: 0.3 ml/L. for 5 minutes dipping or 0.5 ml/L for 3 minutes dipping. Maximum concentration shall be 0.9 ml/L. Sumithion and Lebaycid: Minimum concentration 0.025-0.05%. Immersion time 30-60 seconds. 2. Within the range of concentration of complete mortality, either fumigation of EDB or Phostoxin are not adoptable for the commodity treatment of export banana, because it may cause banana heavely phytotoxicity or hasten the ripening of banana. 3. No further ripening has been found to the banana which was dipped in the practical concentration of EDB solution, i. e., the concentration of thorough killing fruit fly and cause no damage to the fruit. The same banana after ripening process, never change its appearance or its taste. 4. A special design banana sterilization machine which equiped with automatic sprayer has been employed in this experimentation. The data show that the effect of mechanical spray of Sumithion or Lebaycid is rather bad than the dipping method of the same chemicals. However, a better effect can be expected if the treatment time has been lengthened to 60 seconds or more. By such length of time, it can kill all fruit fly eggs or larvae infestaticn in banana even at the comparatively lower ccntcntration of 0.025% or less. Futhermore, the effect of killing would not be affected no matter the banana washed by water before mechanical spray or not