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!

Breaking up ain’t hard to do… if:

  • Don’t water the leaves late in the afternoon, especially if it’s cool
  • Pick up any fallen leaves and dispose of… don’t compost!!!!
  • You don’t overcrowd your plants, Downy Mildew loves no air circulation
  • Don’t overfeed plants with high nitrogen fertilisers… it’s just bad news!
  • Make up a milk mix (about 3 parts full cream to 10 parts water) and spray it on affected plants. It won’t prevent it but it will knock it right back!
  • Excessive overhead irrigation will seriously encourage me!
  • Try some store bought stuff, low environmental impact of course


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

Banner image: Forest & Kim Starr, CC BY 3.0 us, https://commons.wikimedia.org/w/index.php?curid=71901983