Sensitivity of Colletotrichum gloeosporioides isolated from rubber tree to ethephon

ObjectiveThe present study explored the effects of ethephon on growth rate of Colletotrichum gloeosporioides in rubber,spore germination and appressorium formation,so as to provide new measures to prevent and control rubbertree anthracnose.MethodRC169 strain was taken as material,effects of ethephon at concentration of 50.00,25.00,12.50,6.24,3.12 and 0 g/L on RC 169 mycelium growth were detected using mycelium growth rate method and spore germination method.Effects of ethephon at concentration of 0,0.2,0.4,0.8,1.6 and 3.2 g/L on spore germination rate and appressorium formation rate were also detected.ResultWhen concentration of ethephon were at 50.0,25.0,12.5,6.24,3.12 and 0 g/L,its inhabitation rate on RC169 were 98.6%,88.1%,34.7%,25.0%,8.1% and 0 respectively,the regression equation was y=2.9157x+1.9585,R2=0.9518.Spore germination rate of RC169 at different ethephon concentrations (0,0.2,0.4,0.8,1.6 and 3.2 g/L) were 92.20%,36.70%,20.60%,12.30%,2.63% and 0,and the regression equation was y=-1.3945x+7.0663,R2=0.6803.Appressorium forming rate of RC169 were 90.50%,5.37%,3.13%,1.10% 0 and 0,regression equation was y=-1.7383x+6.7965,R2=0.8493.Conclusion When the concentration falls within certain scope,ethephon can inhibit mycelium growth,spore germination and appressorium formation.With the increasing of ethephon concentration,the inhibition rate enhances.