Antifungal activity of plant extracts against Colletotrichum lagenarium, the causal agent of anthracnose in cucumber.

BACKGROUND

Colletotrichum lagenarium is an important plant-pathogenic fungus that causes anthracnose of cucumber, a disease that is widespread under both greenhouse and field cultivation. To find a promising method for the control of this disease, extracts of eight plants from China were screened in the study presented here.

RESULTS

The results showed that the extract of Cinnamomum camphora (L.) Presl had significantly greater inhibitory activity against C. lagenarium than the other seven plant extracts tested in vitro. At 5 days after inoculation in a potted seedling experiment, C. camphora extract demonstrated 95% control of C. lagenarium at a concentration of 16 mg mL⁻¹, and the MIC₅₀ was 2.596 mg mL⁻¹. Microscopic observation showed that this extract had a significant impact on the morphology of the fungus, leading to shorter hyphae that were more branched; this observation was associated with the inhibition of mycelial growth. Stability assays revealed that the extract was relatively stable at 80 °C, under acidic conditions and when exposed to light and short periods of UV radiation.

CONCLUSIONS

These results demonstrated that the extract from C. camphora could be used as a potent phytochemical fungicide.