Effects Of Trichoderma Asperellum T-6 On Growth Promotion And Disease Control Of Tobacco

Tobacco black shank,black root rot and brown spot are caused by Phytophthora parasitica var.nicotianae,Thielaviopsis basicola and Alternaria alternata.They are the main diseases in tobacco production,which seriously affect the yield and quality of tobacco.The control of tobacco diseases mainly depends on the chemicals.Long-term use of chemicals cause drug resistance and pesticide residues.Trichoderma is an important resource fungus,which has certain control effects on pathogens,but lacks the same kind of Trichoderma to control different diseases of tobacco.This experiment determined the biocontrol effect of T.asperellum T-6 on three diseases of tobacco.The results are as follows:1?The inhibition rate of T.asperellum T-6 against P.nicotianae,T.basicola and A.alternata was 49.62 %,59.23 % and 51.18 %.After 7 days,T.asperellum T-6 covered the pathogen colonies.2?The growth-promoting test of T.asperellum T-6 on tobacco showed that T.asperellum T-6 spore suspension had a significant increase in root length,plant height,fresh weight and dry weight.When the spore concentrations was 1×108spores/m L,the root length,plant height,dry weight and fresh weight increased by 58.14 %,32.21 %,67.65 % and 77.44 %.3?The control effect of T.asperellum T-6 on tobacco black shank reached 74.45 %,the incidence rate was reduced by 48.05 % compared with the control.The control effect T.asperellum T-6 on tobacco black root rot reached 75.14 %,and the incidence rate was reduced by 52.01 % compared with the control.The control effect of T.asperellum T-6 on tobacco brown spot is only 26.80 %,the size of the lesion has a significant difference in size.4?The spore suspension of T.asperellum T-6 can increase the content of chlorophyll and carotenoids in tobacco.On the 6 d,the chlorophyll content increased by 50.63 % compared with the control.On the 10 d,the carotenoid content increased by 57.46 % compared with the control.The root activity of tobacco reached the maximum on the 4 d.The activities of peroxidase(POD),superoxide dismutase(SOD)and catalase(CAT),were also increased in tobacco.When the enzyme activity reached the maximum,it increased by 47.26 %,46.78 %and 27.52 % compared with the control.The results indicated that T.asperellum T-6 could control tobacco black shank and blackroot rot effectively,promote tobacco growth.And aslo induce system resistance of tobaccos.