多黏類芽孢桿菌TP3應用於草莓葉枯病之防治

Application of Paenibacillus polymyxa TP3 for the control of strawberry leaf blight

草莓（Fragaria × ananassa Duchesne）為重要經濟作物，臺灣主要栽培產區為苗栗縣，近年因Neopestalotiopsis rosae引起之葉枯病危害猖獗，造成嚴重經濟損失。本研究測試多黏類芽孢桿菌（Paenibacillus polymyxa）TP3是否能用以防治草莓葉枯病。經由孢子發芽及對峙培養試驗，得知TP3具有抑制草莓葉枯病菌分生孢子發芽及菌絲生長的能力。在盆栽試驗，以黃豆粉培養基培養之TP3菌液一週內噴施三次於草莓植株上，可明顯抑制葉枯病之病斑發展，防治率近90%。於接種葉枯病菌前10天單次噴施TP3菌液仍有防治效果，防治率為85%。TP3噴施處理草莓植株後3天，葉片測得最高菌數35,000 CFU/cm^2，第10天之處理葉仍有25,000 CFU/cm2之菌數，故認為草莓葉之TP3菌數對其防治葉枯病具有重要性。田間每10天噴施TP3內生孢子懸浮液1次，噴施7次，由接種葉枯病菌之草莓果實病斑面積較小，得知噴施TP3可抑制葉枯病菌感染草莓果實。TP3噴施10次後，計算草莓開花及幼果之總量較對照組明顯增加。本研究由盆栽試驗及田間處理驗證TP3內生孢子可用以防治草莓葉枯病，減少草莓葉及果實的感染，進一步發展為微生物製劑，將有助於草莓育苗及果實之生產。

Strawberry (Fragaria × ananassa Duchesne) is an important crop and Miaoli is the major area of fruit production in Taiwan. New emerging leaf blight disease incited by Neopestalotiopsis rosae causes immense economic loss in strawberry industry. In this study, whether Paenibacillus polymyxa TP3 can protect strawberry plants from infection of leaf blight pathogen was investigated. P. polymyxa TP3 showed inhibitory activity on spore germination and mycelial growth of N. rosae. In pot assay, spray with TP3 culture fluid in soybean meal medium, containing 80% endospores, could inhibit lesion development of strawberry leaf blight and had near 90% of disease control efficacy. The suppression effect could be maintained while TP3 treatment at 10 days before fungal inoculation and attained 85% of disease control efficacy. Three days after TP3 spray, strawberry leaf had higher detected TP3 population of 35,000 CFU/ cm^2 and the tenth day kept at 25,000 CFU/cm^2 ; thus, TP3 bacterial population should be important for the disease control efficacy of strawberry leaf blight. Furthermore, spraying with TP3 endospore suspension at 10 day intervals in an experimental field for 7 times, N. rosae-incited lesion area on strawberry fruits from the TP3-treated plants could be reduced as observed 7 days after fungal inoculation. The numbers of flowers and green fruits increased as measured after TP3 application for 10 times. Thus, the pot and field assays indicated that TP3 in the form of endospores was applicable for the control of strawberry leaf blight to reduce infection of leaves and fruits. Further development of TP3 bioagent would be useful for strawberry nusury and fruit production.