One of the significant challenges in potato cultivation is the infestation of late
blight disease caused by the fungus Phytophthora infestans. Currently, controlling
the disease using biological control agents, such as the fungus Trichoderma spp.,
is widely promoted due to its potential to reduce negative environmental impacts.
This study was conducted to determine whether the antagonistic fungus
Trichoderma spp. can be used to control late blight disease. The research design
employed was a Completely Randomized Design with a Single Factor, using
different concentration levels as the variable. The results showed that in the
control treatment (G0), the intensity of late blight disease reached 9.72%.
However, when Trichoderma spp. was applied at different concentrations, the
intensity of late blight disease significantly decreased. In the G1 treatment
(Trichoderma spp. 10g/l), the disease intensity reached 8.33%. In the G2
treatment (Trichoderma spp. 20g/l), the disease intensity reached 5.83%. In the
G3 treatment (Trichoderma spp. 30g/l), the disease intensity reached 3.89%. In
the G5 treatment (Chemical fungicide 5g/l), the disease intensity reached 4.03%.
Higher concentrations of Trichoderma spp. resulted in better control of late blight
disease compared to the control and other treatments.