Study The Biological Properties And Bioefficacy Of Chlamydospore And Conidium From Trichoderma Viride

Trichoderma is an important Bio-Control agent against many plant pathogens. It can produce both chlamydospore and conidium as propagule. We contrasted the differences between chlamydospores and conidium respectively obtained under submerged and aerial culture condition on the biological properties and the soil fungistasis to them, as well as their bioefficacy to Phytophthora capsici. The results are listed as follows:1. Temperature had significant influences on the germination of Chlamydospore and conidium. The Chlamydospore normally germinated at 15⁴0℃, and Conidium normally germinated at 20³5℃, but the optimum temperature was 25³5℃ and 30³5℃ respectively.2. The selected carbon and nitrogen resources could promote the germination of both Chlamydospore and Conidium. The five carbon resources used in the experiment could promote the germination of chlamydospore, but there were no difference among them. However there were obvoious difference to the conidium germination. Both chlamydospore and conidium germinated best in the peptone and beef extract solution. But the urea, (NH₄)₂SO₄ and NaNO₃ had negative effect on the spore germination, especially on the spore germination of conidium.3 Both Chlamydospore and conidium had a wide spectrum of pH, the Chlamydospore could germinate at pH 3—10, especially at pH6, and conidium at pH 3⁹, especially at pH5. And no conspicuous effects of illumination were found on the Chlamydospore and Conidium germination.4.The light had different influence to the two kinds of spores.Chlamydospore was able to resist much higher doses of UV radiation than conidium. When the chlamydospore and conidium were exposed to the UV light for 210s, the chlamydospore germination was 66.32%, and however the germination were not found on conidium. And no conspicuous effect of illumination was found on the Chlamydospore and Conidium germination.5. There were obviuous difference in the shelf life of chlamydospore and conidium formulations The initial population of chlaymdospore and conidium were estimated to be more than 10⁸cuf/g.A significant decline was noticed after 180d stored. The number of viable propagules in chlamydospore formulation declined to 10⁵cfu/g, and the conidium declined to 10³cfu/g. So we could conclude that chlamysopore had longer shelf life than Conidium.6.The inhibition of Fungistasis of soil to chlamydospre and conidium was different. Germination rate of laboratory-grown chlamydospore in natural soil was 6.48% after inoculation, and conidium germinated in soil at 1.96%. After adding the exogenous nutrients to the soil, the spores germinated well with the increase of concerntration. the results showed that the spores germinated better in peptone than in starch solution.7. There was no difference about bioefficacy of chlamydospore and conidium to P. capsici. the results indicated that the precaution experiment was more effective than cured experiment using thesame spore solution.In conclusion, chlamydospore was superior to conidium at the aspects of germination, resistance to UV and the shelf life. And also chlamydospore was less sensitive to soil fungistasis than conidium. At the same time, it had the same biocontrol efficacy as Conidium against P. capsici. So chlamysopore had more advantages to be formulated into a new formulation to test bioefficacy.