生物防治為近年來在植物保護策略上最大之改變, 由於過去農藥之過份使用所導致之環境衝擊, 使人類對非農藥之綜合防治特別是生物防治充滿期待, 由於農藥殘留的恐懼心, 使有機農法更是如日中天迅速發展, 因而微生物製劑之開發與利用成為農業上開發之重點.微生物製劑所用拮抗菌種類很多如木黴菌( Trichoderma spp. )、枯草桿菌( Bacillus subtilis )螢光假單胞菌( Fluorescent Pseudomonads )和放線菌( Streptomyces spp. )等, 目前全世界約有四十種防治植物病害之微生物製劑上市, 而木黴菌最高至少有12種( Bio-Fungus, Binab-T, RootShield, Supresivit, T-22G, T-22HB, Trichodex, Trichopel, Trichoseal, Trichoject, Trichodowels, Trichoderma 2000 )之多, 用於防治Botrytis, Fusarium, Gaeumannomyces, Pythium, Rhizoctonia, Sclerotinia, Sclerotium, Verticillium 和木材腐蝕菌所引起之病害.由於木黴菌目前尚無法突破厚膜胞子之量產, 因此這些上市的木黴菌都是以其分生孢子為主之產品, 只有少數厚膜胞子, 因此這些製劑內的拮抗菌對不良環境之衝擊如乾燥、紫外線、不良營養環境, 常無法抵抗或存活, 導致生物防治效果無法發揮到應有之水準.本研究室經多年研究, 目前已經可以以液體發酵生產厚膜胞子, 在振盪培養中其產量經常可以達到10？/ml, 而田間試驗結果厚膜胞子濃度只要10？/ml就可達到防治效果.本計劃選擇兩個木黴菌菌株YT3和AHS-06, 前者可防治立枯絲核菌( Rhizoctonia solani )引起之十字花科幼苗立枯病及腐黴菌( Pythium spp. )引起之猝倒病, 又可促進植株的生長, 後者可有效防治由鐮刀菌( Fusarium orysporum )引起之莖腐病, 過去這兩株菌都是用分生孢子所製造之劑型, 但在田間之發芽率以及產品的貯藏期( shelf-life )都不佳, 且田間試驗時使用製劑的次數要很頻繁才有效, 本計劃希望能以厚膜胞子為主所研發出之製劑, 能更有效的防治適當的病害.Biocontrol is a big change in plant protection strategy recently.The large impact to our environments caused by over used of chemical pesticides is realized.As consequence people are expecting non-chemical integrated pest control especially biocontrol.Due to the chemical residue in agricultural products, organic farming becomes very important to many consumers.Therefore development and use of microbial formulations become main issue in agricultural policy.There are many microorganisms used as antagonists, i.e., Trichoderma spp., Bacillus subtilis, fluorescent Pseudomonads, Streptomyces spp.etc.At present about 40-biocontrol formulation products are in market for disease control.Among them at least 12are belonging Trichoderma, i.e., Bio-Fungus, Binab-T, RootShield, Supresivit, T-22G, T-22HB, Trichodex, Trichopel, Trichoseal, Trichoject, Trichodowels, Trichoderma 2000used to control Botrytis, Fusarium, Gaeumannomyces, Pythium, Rhizoctonia, Sclerotinia, Sclerotium, Verticillium and wood rot fungi.In the fermentation of Trichoderma spp.it is still unable breakthrough mass production of chlamydospores in any solid or liquid media.So above mentioned products in market are using conidia as main ingredient.As known conidia are less resistant to various stresses, e.g., dryness, ultra violet light and poor nutrient conditions resulted in poor performance in the field.After several year investigations, now we are able to mass production of chlamydospores from any Trichoderma spp.In the shaking culture chlamydospore concentration is usually up to10？/ml.And field trials the concentration needed to perform good control are only 10？/ml.In this project two isolates of Trichoderma spp YT3and AHS-06are chosen.The former isolate is able to control vegetable seedling blight caused by Rhizoctonia solani, damping off caused by Pythium spp.and promotion of vegetative growth of the host plant.The later isolate is capable to control stem rot of Taiwan Anoectochillus caused by Fusarium oxysporum.In the past these two isolates were mainly using conidia in the formulation.Although disease control efficacy is satisfactory, however application of biocontrol agent had to be very frequent once every 7-10days.Germination rate of the conidia and shelf-life both were low.Hopefully, in the formulation using chlamydospores as main ingredient will improve all above mentioned disadvantages
