St. Augustine Diseases
I live in Arlington, TX. My St. Augustine, turns yellow, then black then gray. I have used peat moss to acidify the soil, I have sprayed insecticide, I have used an anti-fungal, I have planted sod and plugs. I am fearful my entire yard is going to die next year. I really appreciate any information that can help me treat my grass.
Tarrant County Texas
From the 2 photos you submitted - there are some observable symptoms that are consistent with take-all patch damage. Unfortunately, there can be multiple things that goes wrong at the same time on turf. It appears that you are already doing many actions to help remedy the situation.
My suggestion is to go to the AgriLifebookstore (http://agrilifebookstore.org) and search for publication E-306. This publication should provide some guidance. Additionally, with the various approaches you are using - I would also suggest reading the labels of the products carefully for proper usage applications and rates.
Many times, disease and insect problems are made worse when plants are stressed. Our environmental conditions has not been kind to turfgrasses. You should also consider the following:
proper irrigation (enough water - not too much and not too little, soil should be moist - not wet)
proper fertility (fertilizing at the proper time - there are many different ways to accomplish this. For the DFW area - I would suggest 2-4 light feeding throughout the growing season, starting at green up and last feeding in the fall 2-3 weeks before the grass goes dormant).
Treatments: there are many and combination of them all is NOT always beneficial. If using peat moss, consider 1-2 application of top dress a year, typically done in the early spring (good quality compost can also be used). If using fungicide, make sure that fungicide has effect on the diagnoses pathogen (utilize a diagnostic clinic to get a confirmatory diagnosis). A treatment is the fall on a yard that has previous problem may be beneficial.
If damage area currently is small, consider stripping the affected area plus 1-2 feet buffer area. Properly prep the area and resod.
For additional guidance on area prep, please contact your local Texas A&M AgriLife Extension county office in Tarrant County.