Originally Posted by georgialawn88
i agree w turf dog. i spot sprayed fescue In a bermuda lawn with celcius 3 weeks ago and its dead now. it just takes longer but it seemed to work fine for me
The part about how long it takes for activity in cool weather is the main issue, I think. It also looks like Bayer saw this and made a thinly veiled attempt to correct it. Look at the 3 active ingredients in Celsius:
Iodosulfuron: an ALS inhibitor (which are notoriously slow in cool weather). WHen you dig into the physiology, as soon as Iodosulfuron is taken up into a plant, it is metabolized into metsulfuron, water, and carbon dioxide. So, it's no different than applying Manor, except that it's more expensive.
Thiencarbazone: a PPO inhibitor that causes some contact membrane disruption. This one's no different than carfentrazone (Quicksilver), but a lot more expensive.
Dicamba: You'll see this carboxylic acid in most of your standard 3-way mixes, since it has reasonably quick activity on perennnial weeds and legumes (think dandelions and clovers) in cool weather.
To get the same spectrum of control, you could mix your own Manor and dicamba for a lot less money -- or you could add your own PPO inhibitor of choice to get the quick symptomology you're looking for.