Released April 10, 2009
LITTLE ROCK, Ark. - Practicing good sanitation around landscape plants is one of the best things you can do to prevent plant diseases before the growing season gets started, says Steve Vann, assistant professor/extension urban plant pathologist with the University of Arkansas Division of Agriculture.
"It's best to start these practices just after the threat of the last frost, usually around early to mid-April in Arkansas," he says. "This is the perfect time to clean up around your plants by removing fallen leaves from the ground and pruning dead portions of plants caused by weather damage or previous disease activity."
If feasible, collect and bag all plant debris, then burn it, if your community allows this practice, otherwise dispose of properly, he advises.
A vast majority of ornamental diseases are caused by a diverse group of microorganisms called fungi, according to Vann. These organisms are capable of surviving from one season to another on dead plant parts and on infected portions of plants. They're able to withstand adverse weather conditions for extended periods.
"By removing and destroying all of this dead plant debris, sources of disease infections can be reduced or eliminated, especially if you have had a significant disease history," he says.
Sanitation is especially effective for leaf spots and twig blight diseases. When temperatures begin to warm, many fungi begin actively growing, producing microscopic structures called spores, he notes. These spores may be spread by splashing with water or carried on wind currents to susceptible plant material. These spores are important in the spread of the disease from one area to another.
Rainfall and overhead irrigation are important ways disease organisms can spread. Avoiding overhead water from sprinklers or misters are useful in minimizing diseases, he warns.
"If sprinklers are used, operate them in the early morning hours for plant surfaces to dry by mid- to late morning," he says. Wet foliage can contribute to dieback and blight diseases of woody and herbaceous plants. Early morning watering helps control many turf diseases. To reduce plant stress, always install plants in well-drained soils.
High clay content soils tend to hold water, creating an anaerobic condition to plant roots. This condition can predispose the plants to attack by root rot organisms. By properly installing our landscape plants, you can often minimize plant stress and reduce the need for expensive fungicides that may or may not be effective, he explains.
"Disease organisms can be introduced into the landscape in a variety of ways," says Vann. Some common ways are: Introducing infected plants and seed, infested soil, insects and weeds. It's important to recognize these sources as having the potential to adversely affect the aesthetic value of our landscape plants, he warns.
"Correct disease identification is the single most important first step in designing an effective plant disease control program," says Vann.
An early diagnosis of the disease allows the grower to take correct the problem and reduce economic losses or aesthetic losses. Submitting an appropriate plant sample to the Plant Health Clinic at Lonoke is essential in an accurate diagnosis. It should be collected and submitted fresh. The sample should also be representative of the symptoms of concern.
Refer to extension fact sheet FSA 6114 "Submitting Plant Samples for Disease Diagnosis" for information about plant sample collection and submission. The fact sheet is online at: http://www.uaex.edu/Other_Areas/publications/PDF/FSA-6114.pdf. For more information on this free service and how to collect a good plant sample, contact your county extension office.
--30—
http://www.uaex.edu/news/april2009/0410spring_cleanup.htm
Contact: Lamar James, (501) 671-2187, ljames@uaex.edu
