Downy Mildew attacking impatiens

jennifer28 · January 12, 2013

I just got some news from a friend of mine who owns a large working farm near me. She usually grows several flats of impatiens for me every year. This year she said that Downy Mildew has become a real problem in our area (Connecticut) and that she doesn't want to grow impatiens because there is no sense in giving me doomed plants.

She did tell me that it won't bother New Guinea impatiens, begonias, coleus, or hostas.

But I want to spread the word because I bet a lot of big box stores will still carry impatiens. I may try begonias this year in the impatiens spot. I havent decided yet. But, be warned!

paulgrow · January 12, 2013

It's been a real problem here in Michigan for the past 4-5 years. It affects curbit crops mainly. Now its spread to inpatients.
The spores are spread by the wind.
We have a huge pickle business here in Michigan, a lot of the farmers who raise cucumbers have lost their entire crops.
I hope they can come up with an effective control measure soon.

chancethegardener · January 22, 2013

There is a product, GreenCure, that I have been using for powdery mildew on my cucumber and melon plants. I have been very happy with it so far (as a preventative of course, not for use after disease spreads). It might work for you, too.

babylark · March 5, 2013

My local greenhouse is not growing any Impatiens this year. She said that the mildew will kill them all off. She usually sells thousand of plants and she will have none, cause they probably won't survive.

jennifer28 · March 5, 2013

Quote:

Originally Posted by babylark

My local greenhouse is not growing any Impatiens this year. She said that the mildew will kill them all off. She usually sells thousand of plants and she will have none, cause they probably won't survive.

I know I was really disappointed to find out my friend who owns a farm and several greenhouses will not be growing any either.

Stvrob · March 6, 2013

My peas are starting to get it.

b54red · March 7, 2013

A dilute bleach spray will kill it if you get to it soon enough. I have been using it on my cucumbers and squash for years. Any leaves badly infected will wither and die after the spraying but healthy leaves continue to grow. That is why it is important to spray as soon as the first signs of it show up. If you wait til most of the plant is affected then it will be too late.

Caution: Clorox has strengthened their formula in the past few months so dilution rates must be changed.

zeroma · March 26, 2013

Last week at my Master Gardening class we talked about Fungi: Powdery mildew, Downy mildew and Phytophthore Blight and the bottom line is there is no effective homeowner product.

Some of the best ways to deal with Pathogen like the mildews is to choose the best variety that are resistant or tolerant.

http://www.endowment.org/images/stor...n-sept2012.pdf as great photos of Downy Mildew on Impatiens walleriana

Good gardening practices and understanding of plant pathology are the first line of defense.

Not working in the garden when plants are wet helps prevent the spread of disease.

Disinfecting your tools with a 9 to 1 water and bleach for a minimum of 10 minutes.

Seeds or cuttings from infected plants will also transmit disease.

Many pathogens can survive in infected plant materials, keep the growing area free of plant debris.

Downy Mildew is host-specific, will infect specific variety. looks fuzzy, purple gray and is underside of leaf. It is easiest to see in early morning. Favors cooler wetter environments. There is no effective homeowner product.

Powdery Mildew is host-specific also. Phlox, roses, lilac, maples, dogwoods, about 30 more specific plants. It is white and looks like powder sugar. There is no effective homeowner product.

dvelten · March 27, 2013

We had a lot of powdery mildew last year. I agree with the advice to plant resistant varieties. But if you get mildew, a spray consisting of 4 oz. milk (any kind) to 28 oz. water in a 32 oz. spray bottle, with a tablespoon of baking soda, a teaspoon of Neem oil (if you have it), and a couple of drops of dish soap or insecticidal soap, works pretty well and is safe for the plants. Sounds weird but it works.

January 12, 2013	#1
jennifer28 Two-faced Drama Queen Join Date: Dec 2011 Location: Bellevue Psychiatric Hospital Posts: 955	Downy Mildew attacking impatiens I just got some news from a friend of mine who owns a large working farm near me. She usually grows several flats of impatiens for me every year. This year she said that Downy Mildew has become a real problem in our area (Connecticut) and that she doesn't want to grow impatiens because there is no sense in giving me doomed plants. She did tell me that it won't bother New Guinea impatiens, begonias, coleus, or hostas. But I want to spread the word because I bet a lot of big box stores will still carry impatiens. I may try begonias this year in the impatiens spot. I havent decided yet. But, be warned!

January 12, 2013	#2
paulgrow Tomatovillian™ Join Date: Jan 2011 Location: Allen Park, MI Posts: 178	It's been a real problem here in Michigan for the past 4-5 years. It affects curbit crops mainly. Now its spread to inpatients. The spores are spread by the wind. We have a huge pickle business here in Michigan, a lot of the farmers who raise cucumbers have lost their entire crops. I hope they can come up with an effective control measure soon. __________________ A world without tomatoes is like a string quartet without violins. ~Author Unknown~

March 5, 2013	#4
babylark Tomatovillian™ Join Date: Dec 2006 Location: Lebanon, PA • Zone 6a Posts: 145	My local greenhouse is not growing any Impatiens this year. She said that the mildew will kill them all off. She usually sells thousand of plants and she will have none, cause they probably won't survive. __________________ I can not be held responsible for anything typed above, as I believe my Corgis have learned to type!

March 26, 2013	#8
zeroma Tomatovillian™ Join Date: May 2012 Location: SW Ohio Posts: 637	Last week at my Master Gardening class we talked about Fungi: Powdery mildew, Downy mildew and Phytophthore Blight and the bottom line is there is no effective homeowner product. Some of the best ways to deal with Pathogen like the mildews is to choose the best variety that are resistant or tolerant. http://www.endowment.org/images/stor...n-sept2012.pdf as great photos of Downy Mildew on Impatiens walleriana Good gardening practices and understanding of plant pathology are the first line of defense. Not working in the garden when plants are wet helps prevent the spread of disease. Disinfecting your tools with a 9 to 1 water and bleach for a minimum of 10 minutes. Seeds or cuttings from infected plants will also transmit disease. Many pathogens can survive in infected plant materials, keep the growing area free of plant debris. Downy Mildew is host-specific, will infect specific variety. looks fuzzy, purple gray and is underside of leaf. It is easiest to see in early morning. Favors cooler wetter environments. There is no effective homeowner product. Powdery Mildew is host-specific also. Phlox, roses, lilac, maples, dogwoods, about 30 more specific plants. It is white and looks like powder sugar. There is no effective homeowner product. Last edited by zeroma; March 26, 2013 at 11:11 AM.

January 22, 2013	#3
chancethegardener Tomatovillian™ Join Date: Jan 2011 Location: WV Posts: 604	There is a product, GreenCure, that I have been using for powdery mildew on my cucumber and melon plants. I have been very happy with it so far (as a preventative of course, not for use after disease spreads). It might work for you, too.

March 6, 2013	#6
Stvrob Tomatovillian™ Join Date: Jan 2013 Location: Jacksonville, FL Posts: 1,413	My peas are starting to get it.

March 7, 2013	#7
b54red Tomatovillian™ Join Date: Sep 2009 Location: Alabama Posts: 7,068	A dilute bleach spray will kill it if you get to it soon enough. I have been using it on my cucumbers and squash for years. Any leaves badly infected will wither and die after the spraying but healthy leaves continue to grow. That is why it is important to spray as soon as the first signs of it show up. If you wait til most of the plant is affected then it will be too late. Caution: Clorox has strengthened their formula in the past few months so dilution rates must be changed.

March 27, 2013	#9
dvelten Tomatovillian™ Join Date: Feb 2013 Location: Bolton, MA Posts: 4	We had a lot of powdery mildew last year. I agree with the advice to plant resistant varieties. But if you get mildew, a spray consisting of 4 oz. milk (any kind) to 28 oz. water in a 32 oz. spray bottle, with a tablespoon of baking soda, a teaspoon of Neem oil (if you have it), and a couple of drops of dish soap or insecticidal soap, works pretty well and is safe for the plants. Sounds weird but it works.