| 摘要： 荔枝葉蟎(Oligonychus litchii)及銹蟎(Phyllocoptruta sp.)是近年來番石榴的主要蟲害，發生嚴重時引起果實斑點，影響商售價格。荔枝葉蟎的發生有三個高峰期，分別為1月上旬、7月下旬及11月上旬，平均蟲數分別為28.5 、20.5 及21.5 隻/葉，主要在雨量稀少時密度上升，因此在乾燥期應注意田間的防治。銹蟎普遍發生於5~10 月間，高峰期在5月上旬，平均每幼果達5.1 隻，降雨並非直接影響銹蟎密度的因子，主要是修剪萌芽後密度開始升高，至11月以後較少整枝修剪，發生密度則降低。施用糖漿(受害率7.5%) 、煉乳(受害率 9.4%) 及調味乳(受害率10.9%) 等稀釋100 倍液，可降低害蟎數量。為提高果實的糖酸度，可選用煉乳(糖/酸9.8/0.31 %) 或糖漿(糖/酸9.08/0.33 %) 防治害蟎；如選用調味乳或優酪乳噴施時，會造成果實糖酸度降低。在安全防治考量時，僅有煉乳在防治上較可行性，受害度約在20.6% 。田間評估1%密滅汀乳劑1500 倍、2%阿巴汀乳劑2000 倍、6.5% 愛殺松乳劑800 倍、5%芬普蟎水懸劑1000 倍、85% 加保利可濕性粉劑1000 倍等5種藥劑對番石榴害蟎防治效果，結果以加保利可濕性粉劑及愛殺松乳劑處理後最佳，受害度平均分別為2.5% 及3.1%。The litchi spider Mite (Oligonychus litchii) and rust mite (Phyllocoptruta spp) are important mite pests on guava. They caused severe spots on guava fruits and reduced the market price of the guava. The occurrence of O. litchi had three peaks in earlyJan., nary lateJuly., and earlyNov., embes. The density of O. litchi increased during the low rainfall period, in which more attention on its control were needed. P. sp. had been found between May to Oct. and reached to the peak in earlyMay. It suggested that rainfall was not a direct affecting factor on the density of P. sp., the branch cutting followed by the re-bud of the guava could play a key role in the increare of the mite density. Using different kinds of dairy products, such as, condensed milk and flavored milk, and the syrup to control mites can reduce the number of mites. Furthermore, condensed milk and syrup applied to guava had increased the sugar content and acidity of the fruit, with the Brix/acidity being 9.8/0.31% for condensed milk and 9.8/0.31% for syrup. However, using flavored milk and yogurt had resulted in the reduction of the sugar content and acidity of the guava fruit. As considering the safety of the fruit product, the condensed milk, with the damaged degree at 20.6%, may be the better choice for mite control, Five miticides, Milbemectin 1% EC at the rate of 1500 fold, Abamectin 2% EC at 2000 fold, Ethion 6.5% EC at 800 fold, Carbaryl 85% WP at 1000 fold, and Fenpyroximate 5% SC at 1000 fold, were screened for the control efficacy of O. litchi and P. sp. and the results showed that Carbaryl and Ethion than the others, with the average damaged degrees 2.5 and 3.1%, respectinely. |
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