View Full Version : Difference between diseases and stress
05-26-2002, 01:11 PM
Can anyone help describe how to tell the difference between a lawn that is under "heat stress" and one in which actually has a disease? I've got numerous customers who have irrigation systems and I'm fairly certain they water regularly, but they still have brown areas (these are all Tall Fescue lawns, clay soil, in Raleigh, NC). I don't think these areas are diseased (brown patch) because we've been way too dry. Most of the grass blades are really thin and completely brown. Mowing seems to be fine (sharp blades, correct mowing height, etc.) Other areas of the lawn are fine, only certain areas affected. My Ag agent says the only way to tell is to send a sample to local university, but it seems most other turf pros don't have to do this. I'm losing customers because I can't tell the difference, HELP!
05-26-2002, 06:07 PM
One way to tell disease from stress is to know the conditions under which disease is prevalent. Have you had the conditions that promote disease? Remeber the disease triangle - you need a :1) susceptable host; 2) fungus pathogens present; 3) the right environment (weather or watering practices) and time for the disease to appear.
05-26-2002, 09:24 PM
Get a soil thermometer & a probe. The probe will demonstrate mositure as well as profile, thatch, & compaction properties. The soil thermometer will indicate rootzone temps. The 2 together won't cost $100.
Also see if you can pick up a good turf field guide (small for the truck, not the coffee table) or the popular Turf Disease Chart (send me an email & I'll mail you a set free) & begin to study the visual symptoms of the various diseases. Technically, anything that interupts the normal growth of a plant & cause less than optimum growth is a disease. The problem can be fungal, insect, or environmental. It takes time to get a handle on them all. But you'll do it.
i run into this all the time. not all sprinkler systems are fool proff and some spot watering will be needed.
05-26-2002, 11:51 PM
From your description it sounds like the areas are thirsty.
05-27-2002, 10:04 AM
We have had drought for the last 5 years here in central FL. Hot spots show up on a regular basis when temps. are above 92 degrees. Folks think they have either disease or chinch bugs. So far none of our yards have had either.
We have people lightly sprinkle dry non-bleach laundry powder out at 1 lb. per K or so and water in thoroughly. This helps the ground absorb water after it has become hydrophobic. St. Augustine responds overnite in areas that haven't completely browned.
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