Downy Mildew is a type of fungus that likes wet conditions and infects the undersides of leaves of plants like grapes, cabbages, and lettuce. It reproduces by releasing spores at night that spread in the morning. It thrives in conditions with over 10mm of rain and temperatures over 23 degrees Celsius where leaves remain wet for 24 hours. Common control methods include fungicides and practices like avoiding overhead watering, removing fallen leaves, and not overcrowding plants.

1. Downy Mildew
Hi, my name is: Downy Mildew
Describe yourself: I get really sick of people thinking I am
powdery. He’s my cousin, and, to quote him, I am also a
pretty fun guy (you know… fungi!). I’m a little duller than
him though, some may say grey, but I prefer grey-brown. I
look kinda furry, but I am pretty shy!
Hobbies: Don’t like going out that much, mainly hang
around on the undersides of my favourite leaves (grapes,
cabbages, onions, lettuce, stocks and vines). I like sporing,
but am pretty shy, so I only do it at night for release in the
morning.
Likes: I love it wet, especially when there is 10mm or more of rain, it’s over 23 degrees and leaves
are wet for 24hours. Picky I know, but I just can’t get enough of it! I love water……in fact, my spores
can’t live without the stuff! I love young leaves…..the younger the better!
Dislikes: Hate dry weather, drip irrigation, clean gardens, full
cream milk sprayed onto me, home made bi-carb remedy or store
bought fungicides. I really dislike seaweed solutions in the soil
around the bottom of my plants!
You’ll know you’ve met me when: The upper surface of your
leaves is yellow and patchy, and you can see me on the lower
surface! In cool wet areas, I am the king!
Old School Control Methods: Bayleton, Baycor, Mancozeb Plus
Breaking up ain’t hard to do… if:
Don’t water the leaves late in the afternoon, especially if it’s cools
Pick up any fallen leaves and dispose of… don’t compost!!!!s
You don’t overcrowd your plants, Downy Mildew loves no air circulations
Don’t overfeed plants with high nitrogen fertilisers… it’s just bad news!s
Make up a milk mix (about 3 parts full cream to 10 parts water) and spray it on affected plants. Its
won’t prevent it but it will knock it right back!

2. Excessive overhead irrigation will seriously encourage me!s
Try some store bought stuff, low environmental impact of courses
Photographs:
Pic 1: www.ces.ncsu.edu
Pic 2: www.umassvegetable.org
Pic 3: http://hgic.clemson.edu Description: Downy Mildew symptoms as seen on the upper leaf
surface
Pic 4: www.apsnet.org Description: sporangiophore and sporangia of downy mildew