採收後處理對於控制寬皮柑腐敗之效果

The Effect of Several Chemicals and Fungicidal Waxes on Decay Control in Loose-Skinned Oranges

椪柑與桶柑為臺灣最重要的外銷柑桔，惟因不耐貯連，外銷腐損有高達三分之二者。本實驗旨在研究採收後藥劑及塗臘處理。對於控制椪柑及桶柑腐敗之效果與價值。供試柑桔於果旁作一深0.8~1.1mm，長1.5~2.0cm之十字刻傷。以毛筆用綠微及青微混合孢子之水懸液（每c.c約有孢子一百至一百五十萬個）接種。而後以Dowicide A, Borax-boric acid, Thiabendazole（TBZ）, Benlate（D-1991）等藥劑之水溶液及乳臘消毒。另於接種後0，12，18，24，36和48小時消毒。果實處理後置於68°F及85~90%r.h.之恒溫室內。隔3，7，14，及21天檢查果實之腐爛率。茲將結果摘要如下：（1）晚期採收之椪柑，腐損率甚高。此因果實過熟而使其活力降低之故。桶柑帶葉及果柄採收者，開簍後四天約有百分之三十因機械損傷而腐爛。（2）單以水臘（Fresher 1:10）塗於果面，未能防止微菌之生長。故不應視其有防腐之作用。（3）Dowicide A, Borax-boric acid TBZ, 及Benlate不論是水溶液或加入水臘中均有防腐效果。TBZ及Benlate之水溶液濃度低至250ppm仍有防腐效果。其效果似依濃度之增加而增大。且濃度雖高達2000ppm仍無損及果皮之現象發生。（4）TBZ及Benlate在椪柑接種後置於68°F 24小時內處理，仍有防腐之效果。對於桶柑方面，於接種後置於68°F 24小時內以TBZ處理亦有防腐之效果。但Benlate僅在接種後18小時內處理者有防腐效果。（5）桶柑接種後腐敗速度較晚期椪柑為快，此可能是桶柑於濕季採收，果內水分及膨壓較高之故。及刻傷之深度與腐敗率有關。TBZ及Benlate為最近發現之柑桔果實防腐藥劑。TBZ已得美國食物藥品管理局允許使用，而Benlate則正進行試驗中。故對於臺灣外銷之柑桔，TBZ似乎值得推薦使用。

Several chemicals, namely, borax and boric acid Dowicide A, Thiabendazele (TBZ). and Benlate (D-199l) were tested separately in water solution and wax emulsion for control of penicillium mold decay in loose-skinned oranges. The oranges were scratc-inoculated with mold spores and incubated at 68°F for 0, 12, 18, 24, 36, and 48 hours before fungicidal treatment The inuculation process was carried out by means of a smear with a Chinese writing brush dipped in a concentrate spate suspension (approximately 1-1.5 mil-lion per c. c.) The teat oranges were held at 68°F and 85-90% r. h. for 3 weeks and inspected for decay at intervals of 3, 7, 14, and 21 days after treatment The late-season Ponkan oranges have a higher rate of decay than the mid-season oranges due to a lower vitality. Bath TBZ and Benlate showed a long or antifungal function on mold control than borax-boric acid and Dowicide A and seemed to have a higher fugistat effect on germination of mold spares having effective decay control at the concentration of 250ppm and no peel injury at 2000ppm. TBZ and Benlate in water solution and in wax emulsion were equally effective. However, Fresher water-wax (a commercial wax) alone was not effective to control citron decay. TBZ and Benlate of l000ppm controlled decay in the Ponkan oranges incubated or 24 hrs. With Tankan oranges, TBZ controlled decay in the fruit incubated for 24 hrs while Benlate was only effective in the fruit incubated for 18 hrs. Thus, we would recommend to treat Ponkaw with TBZ or Benlate within 24 hrs after the possible infection has occurred, and Tankan within 18 hrs.