The Effect of Some Chemical Treatments on the Causal Fungus of Pepper Anthracnose Colletotricum acutatum In vitro

Abstract

The effect of some chemical treatments (hexaconazole, azoxystrobin, hydrogen peroxide, potassium nitrate) on the conidial spores’ germination and the fungal mycelium growth of an isolate of Colletorichum acutatum fungal pathogen that causes pepper anthracnose disease in vitro. The following concentrations were used: 1, 10, 100, 500 and 1000 ppm active ingredient in the nutrient culture. The results obtained showed that the fungicide hexaconazole was the most effective, as it inhibited the growth of the fungus by 66.8% at a concentration of 1 ppm, whereas the fungus growth was completely inhibited at concentrations of 10, 100, 500 and 1000 ppm. The fungicide azoxystrobin, produced a higher inhibition rate compared to hydrogen peroxide at concentrations of 1, 10, 100 and 500 ppm, but at a concentration of 1000 ppm, hydrogen peroxide inhibited the growth of the fungus completely, whereas azoxystrobin inhibited fungal growth by 74.4%. The least effective treatment was potassium nitrate, which inhibited fungal growth by 13.7% at the highest concentration. Hexaconazole fungicide was highly effective (100%) at the concentrations of 10, 50, 100 and 1000 ppm in inhibiting fungal spore germination, whereas at the concentration of 1 ppm it only inhibited spore germination by 32.2%. Azoxystrobin fungicide inhibited spore germination rate in the range 1.4%-60.6% at concentrations of 1, 10, 100 and 500 ppm, whereas at the concentration of 1000 ppm it completely prevented spore germination (100%). Hydrogen peroxide had good effect in inhibiting spore germination, and reached 100% at concentrations of 100, 500 and 1000 ppm, whereas at lower concentrations of 1 and 10 ppm it reached 13.5 and 25.8%, respectively. Potassium nitrate had a low effect in inhibiting spore germination at concentrations of 1, 10, 100 and 500 ppm, which did not exceed 40.7%, and at concentration of 1000 ppm, it reached 71.3%.

Keywords:

Chemical treatments, fungicides, pepper anthracnose, Colletorichum acutatum, inhibition of growth, preventing spore germination.