Plan turf disease management now
1 May, 2007 By: Henry Wetzel III, Ph.D Landscape ManagementNow is the time to begin to think about management practices that minimize disease to ensure high quality lawns throughout the summer. Start by considering the need for balance among landscape plants, trees and turfgrass. Recognize that they all compete for water, nutrients and sunlight. Also, be aware that too much shade, or plantings that impede the movement of wind, can increase the leaf wetness duration within the turf canopy. This can increase disease severity.
 Rust |
Knowing soil type and pH are also vital to developing a successful disease management program. Soil pH between 5.5 and 7.0 is sufficient for optimal turfgrass growth and development. Soils that are too acid (<5.5) or too alkaline (>7.0) require adjustment prior to establishment or renovation, and soils high in silt and clay typically take additional time for water to percolate through the profile. Typically, lawns on sandy soils have less disease incidence. However, be aware that drought stress symptoms can be confused with disease symptoms. Make an effort to educate your clients about lawn watering practices and, if they follow your recommendations, this will minimize disease incidence and severity. Irrigate in the early morning as it will not increase the overall length of turf canopy leaf wetness duration.
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In the zone
You can also reduce disease pressures by selecting the turf species best adapted to the particular climactic zone you are working in. Transition climactic zones are the most difficult in which to choose the appropriate turfgrass. The northern-most edge may be too cool and day lengths too short for optimum growth of warm-season turf species. The southern-most edge may be too warm for optimum growth of cool-season turf species. In either scenario, the turf plant is not growing optimally. That makes it more likely to succumb to turfgrass fungal pathogens.
An excellent source of information as to how different turfgrass species and varieties within a particular species have performed within a given climactic/geographic zone is the National Turfgrass Evaluation Program (NTEP). Access this information through the Internet at http://www.ntep.org. Also, consult with a knowledgeable local seed distributor. Ask the distributor for local performance data on the particular varieties, blends or mixtures that are available.
 Summer patch |
The use of fungicides is an integrated component of an overall disease management program. But, understanding the soil physical and chemical properties, making modifications to improve sunlight and air penetration into the landscape, selecting the best adapted species and implementing sound cultural practices, should be addressed prior to using fungicides.
Here are some common turf diseases and some basic management suggestions:
RUST
Pathogens: Puccinia and Uromyces spp.
Primary hosts: Kentucky bluegrass and perennial ryegrass, but can occur on any turfgrass species
Environmental conditions conducive the disease development: cool, wet, low light intensity, weather of primarily the fall and spring
Rust disease in turfgrasses is probably one of the easiest to diagnose. With a hand lens, note small collections of spores, often referred to as pustules, that have an orange to reddish-brown color to them, on the leaf surface. When observing the turfgrass, from a distance, symptoms take the appearance of a general chlorosis or drought stress.
 Brown patch |
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