Ways to Kill Anthracnose

Disease Cycle

• The spores of the disease causing fungi overwinter in their dormant state beneath the plants in the fallen foliage. Some fungal spores also persist in the infected twigs still on the tree. The spores start to resume growth under favorable growth conditions, primarily the warm and moist spring weather. The fungus spreads rapidly with splashing water to the newly emerging buds and foliage.

Cultural Control

• Good sanitation practices are among the best ways to kill existing fungus in the landscape and to keep the disease from reoccurring the following season. Clear all fallen foliage and twigs from under the infected plants and destroy them. Prune off as many branches and twigs from affected plants without harming the plant. Apply fertilizer to affected trees after spring rains and after all the foliage has grown. Avoid the use of overhead irrigation as this causes moisture to remain on foliage for prolonged periods, encouraging fungal growth.

Chemical Control

• The use of chemicals for anthracnose control is most effective when timed properly. Fungicides work only as a preventative control strategy in protecting healthy tree tissues and are not a cure once an infection has occurred. Recommended fungicides include products containing propiconazole, thiophanate-methyl or copper based fungicides. Treat healthy plants with chemicals early in the season, before the start of spring rains. Repeat application after two weeks as new growth appears, making sure that all plant areas are covered.

Turfgrass Anthracnose Management

• Anthracnose frequently appears on turfgrasses during prolonged moist, dry or hot temperatures ranging between 80 to 90 degrees Fahrenheit. Host grasses include bluegrass, fescues, Kentucky bluegrass, perennial ryegrass and bent grasses. Grasses that are deficient in nitrogen, are mowed at improper heights or those suffering from drought are more prone to the infection. To minimize chances of infection dethatch lawn regularly, water well and keep mowing height at 1 ½ to 2 ½ inches. Do not remove more than one-third of blade length during each mowing and water lawn in the morning. Healthy cultural management is usually sufficient in controlling disease.