15% chance of rain

Seemed like the perfect day to spray chufas. Wasn't a cloud in the sky at 10 am; now it's raining. Spraying with a 25 gallon ATV sprayer containing 10 oz Clethodim, 2oz Milestone, and one pint of surfactant. One patch went 3 hours without getting wet, next one about 90 minutes. Third one maybe 10 minutes.

Ag experts, what do you think? It hasn't rained a lot, but enough to wet the fields. I've got 2 fields with Bermuda and Johnson grass. If I wait to see if the Clethodim worked, they will have really taken over the field. But spray them again and if it stuck the chufas get a double dose and probable herbicide damage. So what to do?

PCP,
It is very species dependent. However, you are probably ok with 3 hours. 1.5 hours may show some activity, but not what you want. 10 minutes will need to be resprayed. Even a light rain can negatively impact performance.

As long as the surfactant holds you should be alright on the first two. The third you are probably screwed.

Thanks, 007 and Turkey neck, that's about what I figured. And to make it worse, Intellicast said there was a 1% chance of rain at 4 pm, so I went ahead and sprayed the 4th field. 30 minutes later it is coming a downpour.

I guess I will just spray the last 2 again tomorrow.

Like washing a car without a cloud in the sky.

Yep. Now another question - everything is wet, but it looks like it won't rain again until tomorrow afternoon. I have never liked spraying until the dew is gone, but that will probably not happen until noon tomorrow. How critical is it for the plants to be completely dry? The choice is likely gonna be to spray a wet field or let the weeds continue to get ahead of my chufas for another week or so.

I've been growing chufas a long time, never seen a year like this.

Not ideal, but probably won't matter that much for what you are doing, PCP.

Thanks, guess I'll spray it again. Gotta feed my starving family.

Don't complain about a rain in July or august PCP

I'm not complaining but the concern is growing. Got 2 different trucks stuck 5 times in 1 day earlier this week. Watched a dozer pull out a Tiger Cat yesterday morning on a place I thought was dry. Rained out yesterday by 8 and way behind.

It beats drought for sure. Still, making a good crop of Johnson grass ain't much better than making nothing.

Now they say 50% chance of rain by 9 am. Guess I will forget it.

Weather forecasts are absolutely useless this time of year. Wasn't a cloud in the sky at 10 am so I resprayed the last 2. But the spraying yesterday stuck to some extent because the morning glories are already dying. I've noticed that the Milestone works much faster on the broadleaf weeds than the Clethodim does on grass.

Usually you can't take what labels say on rainfastness and cut it in half. Not all the time but most.

Milestone has some soil activity. 2 ounces is pretty low, but Morninglories are fairly sensitive. Most grass herbicides take a little longer to show activity.x

Thanks, and that was the reason I was hesitant to spray again the next day. Others have told me they used 4 oz of Milestone without hurting chufas. Guess I will find out if I got away with it.

Milestone is absolutely death for morning glories. I sprayed a patch a few weeks ago and they were starting to shrivel up 3 hours later. Amazing it can work that quickly.

Thanks to all for the replies. I'll post the results next trip.

I promised pics of the results of the spraying when I was dealing with rain. The first patch that was sprayed a few hours before the rain looks fine.



The second patch doesn't look quite as good and has more weeds, but it's still ok and should make a good crop. The third patch that got sprayed twice shows a lot of Clethodim damage. The fourth that also got sprayed twice does as well. Here's a pic of it.



The Clethodim damage is pretty severe, but I would have made nothing in this field if I hadn't killed the Johnson grass. I let it get way too big before spraying, but we went a couple of weeks without a day that was dry enough to spray. Even this field should still make a lot of chufas, and the other end didn't have Johnson grass so I didn't spray it the second time and it looks good.

Just to show the difference, here is a pic of the other end of the last field. I turned around about where the pic starts because the Johnson grass ended here. You can see the yellowing chufas at the front, but they are just green after that.



If I am ever in this position again, I don't think I will risk another spraying. Also, I am having second thoughts about Clethodim being the best grass herbicide for chufas. I've had more than one field damaged by it the past 2 years, and I don't remember having this back when I used Poast. I'm using a different brand of Clethodim from what I did prior to last season, so that could be part of the trouble. If I do use it again, I'm gonna cut back to 8 oz per acre.

Thanks for all the help.