TechNotes Oct. 28 – Rust, Late Seeding and Soil Temps

RUST IN COOL-SEASON TURF. With the arrival of cooler temperatures through the Midwest, cool season turfgrass growth has slowed. Rust is becoming more evident. Leaves that are showing rust symptoms have orange pustules present on the leaf surface. Although rust is often associated with dry conditions, the wet cloudy conditions have been favorable for this disease. At the moment rust symptoms are most noticeable within the drip line of trees, and shaded areas along side homes. If symptoms are severe enough, walking through an infested lawn may result in shoes and pant legs turning orange.

At this time of the year, fertilizing to promote growth may not be advisable due to the probability of reducing the turf’s winter hardiness. Fertilization should be applied as a late season application. A fungicide application could be made if disease severity is great. If not, it may be wise to remove clippings after mowing, and pruning landscape trees to increase light penetration.

TOO LATE TO SEED? As cooler temperatures settle in across the northern United States the question often raised is how late can one seed? For most of the northern United States the ideal seeding window has passed. The decision to seed now is risky. If seeds germinate over the next several weeks producing seedlings that do not have a chance “harden off” prior to winter, turf kill often occurs. Dormant seeding - the fall planting of seed where germination does not occur until spring, is done when soil and air temperatures are low enough that germination does not occur would be recommended. In the Midwest, current temperatures remain relatively high. Dormant seeding should not be attempted until average soil temperatures fall below 50 F. A problem with dormant seeding is that the potential for a high seed mortality based on environmental conditions (wet cold conditions) may occur.

SOIL TEMPERATURES.