تاثیر عصاره‌های گیاهی در مقایسه با قارچکش‌ها در کنترل بیماری آنتراکنوز گل‌ها و گیاهان زینتی

The fungus Colletotrichum gloeosporioides is a significant pathogen affecting both annual and perennial plants, causing anthracnose disease in a wide range of agricultural, horticultural, and ornamental plants, totaling 283 species, in both warm to cool and humid regions worldwide. Symptoms of anthracnose include leaf spots, cankers, dieback, and fruit rot. The most important strategy for controlling this disease is spraying the aerial parts of plants with effective fungicides. Given the limitations of using fungicides in residential and office spaces to control anthracnose in flowers and ornamental plants, non-chemical methods such as using plant extracts are prioritized. In this research, extracts from savory (Satureja hortensis), rosemary (Rosmarinus officinalis), peppermint (Mentha piperita) and Shirazi thyme (Zataria multiflora) plants, extracted using 70% methanol solvent, were compared with the fungicides mancozeb (Dithane M-45), iprodione + carbendazim (Rovral TS), and tebuconazole (Folicur) for controlling anthracnose in ornamental plants. To this end, the inhibition of mycelial growth of the fungus in potato dextrose agar (PDA) culture medium was investigated using the mixed culture method, meaning the extract or fungicide was first added to the culture medium, and then a fungal colony disk was inoculated onto it, and the growth rate of the fungus was measured for three days. All extracts were tested at doses of 1, 10, 100, 500, 1000, 10000, 25000, 50000, 750000, 80000, 85000, 90000, 95000, and 100000 parts per million (ppm) with 4 replications. Fungicides were also tested at their registered doses. To ensure the results, the experiment was repeated. The results obtained from comparing the average mycelial growth and the percentage of inhibition of fungal growth of Colletotrichum showed that the highest mycelial growth was observed in the treatment containing savory extract (6.78 mm/day) and the lowest mycelial growth was observed in the treatment containing rosemary (6.41 mm/day). Treatments containing peppermint, rosemary, and thyme extracts (6.46, 6.41, and 6.46 mm/day) were in one statistical group, and the treatment containing savory extract (6.78 mm/day) was in another group. All fungicides showed 100% inhibition of mycelial growth of the Colletotrichum fungus. The overall conclusion is that all three fungicides were able to completely prevent the mycelial growth of the Colletotrichum fungus; however, there was no significant statistical difference between the four plant extracts. Nevertheless, rosemary extract caused the greatest inhibition of mycelial growth of the Colletotrichum fungus. Based on this result, it is suggested that further studies be conducted to formulate the best extracts.