It should be under 80 degrees to spray, but if you do it in the evening when the sun is not shining on the roses, you should be OK.

Since the Bayer is a systematic, as soon as it dries on the plant (about an hour) you can water, it will not run off.

Spray before nine in the morning and you will be alright.I spray every Tuesday-only thing I worry about is rain.You can spray tomorrow Evening.Once the sun is on the horizon and not overhead.I don't spray Daconil over eighty but I only use that in the winter as there are some fungus Bayer does poorly on.I never worry about the temperature with Bayer-its the suns intensity thats the problem this time of year.

I water well in the evening and then spray early morning before it gets too hot. If I didn't spray when it was hot I wouldn't spray from April till October. I spray weekly and as long as they are well watered and you don't spray them mid day they should be good. I try to not spray in the evening. I want them to have time to dry.
Nancy

Fungicide in the evening isn't going to cause fungus-lol
I never worried about the plants being hydrated before spraying as the spray does that.

OK, thanks. Forecast is for a cloudless sky tomorrow so I'll water well in the morning and spray tomorrow evening.

Barbara

The best time to spray in hot weather is in the late afternoon thru twilight time, ie., after the sun has dropped below the horizon. Be sure to water deeply at least six hours before you spray to be sure those plant cells are as full of water as possible. This will cut down on heat stress, and roses stress very easily in hot weather. Sometimes, when the heat has been very oppresive, I have cut the spray dosage in half, but wether you do so or not, is up to you.

I've never understood why some people think it's better to spray in the evening than the morning. In the morning the roses are well hydrated, while in the evening they may be recovering from moderate water stress during a hot afternoon, even if recently watered. Sprays with copper should not be used in the evening, because they need to dry fairly promptly and not soak too long. I have long experience with phytotoxic materials like sulfur and Daconil, and I normally spray these in the morning. Evening is fine, though, for anything but copper.

I haven't heard a single report of Bayer or Banner (alone or with mancozeb) burning rose foliage. You shouldn't spray the systemics in the hot sun because they will dry before the needed one-hour absorption time. Otherwise, I wonder if people are fretting needlessly.

They are but thats what people do.lol

Things that can burn:
copper (in cool, damp conditions)
sulfur
any oil
soap
baking soda
potassium bicarbonate
Daconil
folpet
excess of glycol spreader-sticker
many miticides

Things that don't burn in normal circumstances:
Bayer
Banner & other propiconazole
mancozeb, maneb
Immunox
Cleary's
Avid (?) (no experience)

Michael, I love to fret ;-) Seriously, thanks for the information--it's good to know that Bayer won't burn.

Barbara

Now, Barbara, I didn't go that far :) I just said I'd never heard of it. But fretting is part of the whole rose deal, isn't it?

The Ortho fungicide with triforine is also non-phytotoxic (normally).

Oh, yes, it is definitely part of it. Thanks again.

Barbara

Playing devil's advocate for a sec---I spray every Saturday. Sometime after coffee and before dinner. As long as it's not raining (or about to) I spray because if I don't I'll forget completely. Never had a problem with burn from Bayer.

PS, just came back from vacation and the roses went CRAZY in my absence! Must take pictures...

Elaine

Thanks for sharing your experience, Elaine!

Barbara

Like Nancy said, if I never sprayed when the weather was too hot, my roses would go un-sprayed at least half the year. Whether Banner Max, Ortho triforine, or Bayer tebuconozole (sp?), I've never had a burn problem from anti-fungal sprays. I HAVE burned roses with chemical fertilizers a number of times. Ouch!
I always try to make sure the plants are well-watered before spraying, but honestly, I don't count out 6 hours. Sometimes I spray an hour after watering. And I've sprayed morning, mid-day, or early evening, just depending on my hectic schedule. It certainly dries fast at mid-day, but if that's preventing a needed absorption period, I can't tell, because I still haven't had any blackspot in ages--ever since I started spraying some of the time with Bayer Advanced Disease Control. That stuff is a miracle product! (I do alternate it with Banner Max, since I already have a good supply of the Banner Max). Might as well keep the fungal spores off-balance.

Mike

I too have black spot on my David Austin roses and I’ve bought Bayer Advanced Disease Control to spray them. Should I also be spraying for insects and if so, what is best to use? My roses are 3 years old and I live in Texas.

I just fertilized them this morning with David Austins Rose Food and watered it in well. Will it hurt them to spray the Bayer 1 day after fertilizing?

Thanks in advance for any comments I might receive.

Karen

Thankyou so much for the advice.