Summer Time Diseases and Maladies


Pythium Blight

This photo was taken around July 21, 2003. It has been a particularly bad season for fungus. The disease spreads very fast in the warm, humid conditions. Mycelium is obvious in these images. Keep clicking on the pictures to zoom in. For more on the subject see:

 "Pythium Blight", Richard L. Duble, Turfgrass Specialist, Texas Agricultural Extension Service

"Pythium Blight of Turfgrass", John E. Watkins, Extension Plant Pathologist, Robert C. Shearman, Turfgrass Specialist

"Controlling Pythium Blight on Overseeded and Established Turf", ANR-594, New July 1993. Austin Hagan, Extension Plant Pathologist, Professor Plant Pathology, Auburn University


Red Thread

 A unique disease that attacks the grass blades and causes a reddish orange color. Besides the grass, it coats and discolors equipment and shoes. It is most prevalent in hot and dry conditions. Click on the pictures to zoom in closer.

These images were taken on August 4, 2002, the 6th day of a mid summer heat wave. Temperature from 95 to 100 degrees Fahrenheit with humidity over 90% was common. During this period virtually all areas had to be watered extensive to prevent damage from excess drying. Many problems not typical of cooler months were encountered such as cutworm infestation and damage from foraging animals, fungus attack, rapid drying out and death of turf plus damage and death due to mowing while too hot.


Pythium blight: An aggressive fungus that thrives during periods of high heat and humidity. Beginning as a small dot, it rapid grows out from the center while attacking healthy grass. It can progress to rings several feet in diameter in a single day. If rapidly treated it is non-fatal. If left untreated it will kill bentgrass. This disease can be, for the most part, prevented by the regular application of appropriate fungicide prior to and during warm, muggy summer weather. If it remains unchecked for even short periods, extensive damage and death may occur.

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Damage and death of patches due to mowing on a sunny, drying day while temperature was in vicinity of 100 degrees F.









Death of bentgrass due to advanced stage of summer patch infestation.

Death of bentgrass due to burning by  micronutrients applied during extremely hot periods. One should be cautious to apply the materials during cool periods only. Unfortunately this is not always possible, and application of materials at curative rates may actually damage bentgrass if freshly applied during very hot periods.

Crabgrass grows and thrives in hot, humid conditions. It is best prevented with the use of pre-emergent. Large patches can be treated as long as the plants are not too mature although bentgrass typically suffers damage in the process. Weeding is an effective means of removal of crabgrass without damaging bentgrass.






Excessive drying and death of localized areas due to shallow installation of bunker drainage

Cutworm killed by application of insecticide.

Damage from squirrels foraging for insects or other food stuffs under turf.

Two-tone appearance of green due to application of two separate types of micro nutrients.