please tell me what this is?

jules1964

I have discovered this white stuff all over my asters. The foilage below is dead, but the top is still alive but covered in white stuff. Does anyone know what it is and how I can get rid and save the plant.

thanks.

http://i797.photobucket.com/albums/yy251/jules_1964/photo2.jpg

20400keith

Is the white stuff like a powder? If so, it sounds like powdery mildew.

Provide adequate air circulation (thin out the plants if necessary). Remove and destroy infected leaves and flowers, and avoid fertilizers high in nitrogen that promote new growth, which is more susceptible to infection.

Powdery mildew is unsightly but doesn't usually kill plants.

jules1964

20400keith wrote: »

Is the white stuff like a powder? If so, it sounds like powdery mildew.

Provide adequate air circulation (thin out the plants if necessary). Remove and destroy infected leaves and flowers, and avoid fertilizers high in nitrogen that promote new growth, which is more susceptible to infection.

Powdery mildew is unsightly but doesn't usually kill plants.

Thanks Keith, the whole of the leaves are infected and the lower ones have gone brown and died.

20400keith

Yes, this happens with powdery mildew. It doesn't look good but it shouldn't kill the plant.

Powdery mildew often occurs in mid to late summer. It flourishes when we have cool evenings and warm, humid days.

You can treat powdery mildew with a fungicide.

Good luck!

elsien

You can get sprays to use on powdery mildew if you wish. I've never bothered, as I find it's better to get a bit more air circulation going. Lack of water can make it worse as well, apparently.

amcluesent

It's a bad year for mildew on my asters, I reckon the water stress in the Spring.

emiff6

I agree with what Keith has said, jules, and I would add, don't cut into healthy growth with secateurs that have cut mildewed growth - clean in water with a drop of bleach added, otherwise you may spread the mildew spores picked up on the secateurs onto the fresh healthy cut.

Sulphur is the best cure/preventative for mildew, and as garlic is high in sulphur, you can make a spray by crushing or whizzing up a few cloves with water, then strain and spray on the leaves. Or buy commercially available products.