Rust Diseases on Home Lawns
Rust appears as an orange or yellowish-orange powder (spores)
on grass leaf blades, especially in late summer to early fall when
the weather is dry. Rust typically develops on lawns growing very
slowly. Overall, the turf may assume a yellow, red, or brown appearance.
Close examination will reveal the pustules, which easily rub off
on your hand. Rust spores can easily be tracked into homes.
Low fertility (in particular nitrogen) and low water availability
slow down turf growth, allowing rust to develop. Seasons with excess
rain may have rust outbreaks due to depletion of available nitrogen.
Cool nights with heavy dew and light, frequent rainfall add to the
ideal conditions for rust to develop. Warm, cloudy, humid weather
followed by hot, sunny weather also favors rust development on lawns.
Kentucky bluegrass, perennial ryegrass, and tall fescue are all
affected, depending on cultivars. Rust spreads via air, water, shoes,
equipment, and vegetative turf material (sod). Rust may weaken turfgrasses
and make them more susceptible to other problems.
Control rust through sound turf management. Begin by choosing a
quality turfgrass seed blend of several cultivars of the species
desired for the site. Resistance to rust can vary according to the
race of the disease present. A diverse turf stand helps combat rust
and numerous other turf problems. Maintain lawns through sound watering,
mowing, and fertilizing. Water early in the day so the grass dries
quickly. Manage problem thatch. Increase vigor with an early fall
nitrogen application, but don't overdo it. Check soil phosphorus
and potassium levels through soil testing. Also assure good airflow
over the site and light penetration by pruning trees and shrubs
in the area near the lawn.
When rust occurs in late summer, improved growth conditions of
early fall often get lawns growing more vigorously and the rust
fades away. Early September is a key time for fertilization. If
conditions are dry, irrigation is also needed to increase the growth
rate of the lawn. Fungicides are rarely suggested on home lawns
for rust control. Focus on cultural practices described above.
August - September 2002:
Purple Plants Can Be Pesky
Rust Diseases on Home Lawns | Spring Bulbs
Late Summer ‘Do’s and ’Don’t’s
| Fall Lawn Care