根粉蟎為害洋蔥調查及其防治試驗

Abstract

根粉蟎Rhizoglyphus echinopus ( F. & R. )，分佈全球，普遍加害球莖類植物。1978 年本省外銷日本之洋蔥，被發現該蟎類之為害。貯運之球莖及田間之腐壞球莖均遭侵害，並在其中腐食孳生。和其鄰接之健全球莖亦往往被傳佈為害。定植後之洋蔥撒施Temik 粒劑未見防治之效，因係根粉蟎之密度太低。採收後之洋蔥用3 磅溴化甲燒在42.5 m3之室內燻蒸2 小時可得理想之防治效果。惟有輕微之藥害現象。 Acarid bulb mite, Rhizoglyphus echinopus (Fum. and Rob.), has been known for its cosmopolitan distribution and to be found in bulbs of amaryllis, crocus, Easter lily, gladiola, hyacinth, narcissus, tulip, garlic and onion, sometimes on rice straw. Shipments of these plants are usually infested with this mite. In the spring of 1978, numerous acarid bulb mites were found on the bulbs of Taiwan onions during their exportation to Japan. A preliminary investigation and control program was conducted thereafter. Mites were mostly found on the rotting bulbs, about 15% of the third healthy bulbs were also infested. 20 kg of Temik 10 G per hectare applied 5 days after onion planting, no significant effect was shown since the population of mites were low and found infestating on the rotting bulbs only. Two hours fumigation of methyl bromide at dosage 3 lb/42.5m3 could get good control against those mites and their eggs, only slight phytotoxicity was seen.