慣行與永續農法對水稻田瓢蟲之影響

Abstract

本研究呈現2014–2020 年於嘉義縣溪口農場及雲林縣雲林分場農業試驗田區，調查不同農耕下田區之瓢蟲種類及數量之結果。於溪口農場及雲林分場黃色黏板分別調查到11 種及12 種瓢蟲，其中六條瓢蟲是數量最多之瓢蟲，分別占所調查到瓢蟲數量之83.1% 及79.2%。慣行農耕及永續農耕田區調查到瓢蟲數量及種類數沒有差異。水稻田與落花生田調查到瓢蟲數量與種類數並無差異，但二期作落花生田調查到瓢蟲種類顯著少於一期作水稻田。溪口農場慣行農耕及永續農耕田區比較，噴施殺蟲劑明顯降低農友操作田區瓢蟲種類及數量。本試驗結果顯示，六條瓢蟲於慣行農耕、永續農耕及農友操作田區，均是最優勢的捕食性天敵，這項資訊有助於未來研究人員發展水稻害蟲生物防治策略，降低農民對化學農藥的依賴，但是在此之前應避免隨意使用化學農藥，以利保育六條瓢蟲這些重要的捕食性天敵。 A field survey was conducted during 2014–2020 for lady beetles in different types of farming fields in Chiayi County Sikou farm and Yunlin County YuinLin branch Station. Results showed that 11 and 12 lady beetles were captured with yellow sticky paper in Sikou farm and YuinLin branch Station, respectively. Among lady beetles, Cheilomenes sexmaculata (Fabricius) was the most dominant lady beetle in all types of framing fields, occupying 83.1% and 79.2% of the total lady beetle number separately. There was no difference in lady beetle species and quantity between conventional and sustainable agroecosystem fields and also between second crop season lowland paddy and upland groundnut fields. Significantly fewer lady beetle species in second crop season upland fields than first crop season paddy. Insecticide application significantly reduced lady beetle species and quantity in farmer-practiced fields compared with no chemical-treated conventional agriculture and sustainable agriculture fields in Sikou farm. The results of our tests showed that C. sexmaculata was the most dominant lady beetle in different types of farming fields. This study presents useful information for future workers to develop biological control strategies for paddy pests, which will be useful in reducing the farmers’ dependence on harmful chemical pesticides. However, there is a need to conserve C. sexmaculata these important beetles by avoiding the indiscriminate use of chemical pesticides.