I have known about inherently resistant weeds being treated with non effective products causing a population shift and weeds where resistance was induced due to excessive use of one class of chemistry. The emerging nightmare in Hawaii is goosegrass resistant to both Revolver and Triazine herbicides. There are also specimens less susceptible to glyphosate as well. Revolver resistance is actually the most severe problem. This one could not be pinned on the lawn guys. 99% of the Revolver, simazine, and Sencor is sold to golf courses. Goosegrass thrives in saturated and compacted soils that are also nutrient poor. In an attempt to save money, fertilization was cut, instead relying on more water to keep grass green. Fast answer is to mechanically aerate. Well, I have discussed the effect of aerating soils where base content and ratios are incorrect. My chemical vendor is frustrated. Mention applying a soil appropriate product like gypsum or calcium nitrate and the sound of checkbooks slapping shut can be heard. Plenty of money to spend on Revolver, Specticle, Tower, and Sencor+MSMA if that does not work. The problem of resistance does become my problem. On a tiny island, odds of a goosegrass seed from a plant surviving every legal herbicide dropping into a residential lawn are high.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738