木瓜白粉病之田間消長與藥劑防治

Abstract

木瓜白粉病在臺彎南部春季發生嚴重，通常於1 月份開始發生，至3- 4 月為發病最盛時期, 4 月以後氣溫逐漸上升，雨量增多，發病亦逐漸減少。在網室內以木瓜幼苗進行藥劑試驗，由19 種可防治作物白粉病之藥劑中，篩選出防治效果佳，且無藥害產生之藥劑共四種，為70%可濕性硫黃粉，93 為免賴得一S 可濕性粉劑，25 %布瑞莫乳劑和75 %多保淨M 一銅可濕性粉劑，以此四種藥劑與植物保護手冊現行推薦使用之三種藥劑進行田間藥劑防治比較試驗，於白粉病發生初期開始，每隔10 天噴藥一次，連續噴施三次，結果顯示此四種藥劑與己推薦之藥劑均有優異防治效果，又系統性藥劑50 %免賴得可濕性粉劑與70 %可濕性硫黃粉劑交替使用亦可得優異防冶效果。 Powdery mildew of papaya, caused by oidium caricae Noack, started in January, and became severe in March and April. in southern Taiwan. The disease decreased after April due to the warming temperature and raining season. In order to obtain effective fungicides for the control of this disease, 19 chemicals were preliminarily tested on the papaya seedlings in the net-house and the results indicated that 70% sulfur W. P., 93% Benlate-S W. P., 25% Nimrod F. C. and 75% Topsin-M do W. P. were satisfactory. The efficacy of these four fungicides were compared in the field test with the three recommended fungicides listed in the plant protection manual. The Fungicides were sprayed three times every ten days after the disease became visible. The results showed that they were as effective as the recommended fungicides. The alternate use of 50% Benlate W. P. and 70% sulfur W. P. also gave a satisfactory control in the field.