Aquilegia Downy Mildewed Leaves
|COMPARISON:||TOP OF LEAF||UNDERSIDE OF SAME LEAF|
|These have not yet sporulated on the underside of the leaf.
The yellowyness is much more pronounced on the top of the leaf.
|It is very easy to see the angular edges of these yellow areas, and clearly see how they are delineated by the leaf veins.|
|Now there has been moistness, probably rain, and the DM
responds to the warmth and high humidity by growing out of the
underside of the leaf. Now it can sporulate to produce millions
of tiny, asexual spores.
This external growth may be seen, especially with a hand-lens, as fluffy, downy white (off white) growth.
|Hint: keeping leaves that are NOT yet showing any external
growth in a plastic bag with a wet tissue for a time, may
encourage growth that you can see. Or rot the leaf.
Hint 2: 'older', wettened, growth may no longer look fluffy, imagine the difference between dry and wet cotton wool. Difficult to see.
Hint 3: Use a camera with macro for a close-up photo, then view at magnification on your computer screen.
Later, affected tissue can turn browner, these darker lesions
are easier to see ...but you have missed your chance, a lot of
spores have already been released.
Particularly seen on golden or variegated foliage, where it is difficult to see the yellowy patches.
|DM hasn't deterred some aphids!
|Oops, the start of powdery mildew as well as downy mildew on this poor aquilegia leaf.|
|What are these holes? Slugs have been grazing; the fungal
hyphae (fibres) are nutritious, even if the aquilegia leaf is
poisonous. Here's a close-up:
Nothing particularly obvious here... yet look what a close scrutiny of the underside shows.
|This leaf just looks generally chlorotic, but look how much growth there is on the underside.|