I dont see anything other than immature leaves? PM is generally white and well.. powdery :)

How about aphids or other bugs?

Hi Scott-
It seems to me that these leaves are whiter, scrunched up, fuzzier, and wavier than most of my other trees leaves. I don't see any aphids, and I did do a couple dormant oil sprays. When I Google, I see Powdery Mildew pics and {{gwi:99914}} and that seems to resemble my situation. My other leaves seem to look different than these. Last year, I ran into the same thing with 1 other tree and thought it was PM. Thanks, -Glenn

Those just look like young leaves to me.. Every tree grows its leaves in a different way.

Scott

Ok, thank you Scotts. Maybe I spend too much time staring at my trees. :-)
-Glenn

Glenn:

I think your first photo definitely shows powdery mildew, but just a touch; the second, I don't see it. When I see this disease, I usually prune it off immediately and put the prunings in the trash, but since those are very young trees you might not want to do that. If Immunox is effective against PM, I would spray it now. I use a fungicide called Topsin in my early cover sprays, but I got it from a commercial source and it is not widely sold on the consumer market.

In my experience, PM is more likely to be widespread in warm, even dry weather. Cedar apple rust is the one that enjoys cool, rainy, windy weather. I have a couple of trees that are highly susceptible to PM; the others are not. One tree, a Jonagold, is so susceptible that the PM can end up covering the entire tree unless I take preventive measures. I don't know how to explain this, but if you have a susceptible tree it is better to be safe than sorry. PM can weaken the ability of a tree to support fruit to such an extent that any apples that have set just don't grow up. At this stage, when your trees are very young, you want them to grow as quickly as possible.

I would probably remove any apples that set and hold on this tree to allow it to direct its energy to growth.

Don Yellman, Great Falls, VA

Thank you Don as always! Ok, so maybe IÂm not seeing things. Glad to see that IÂve caused a discussion even among the experts!

I originally took that 2nd picture as a contrast to show to what my other good leaves looked like, but then, looking at that pics some more, I started to wonder. Anyway, I agree. The second pic is fine.

Yes, Immunox is indeed effective against PM. See this table from Cornell. Myclobutanil gets a 4 out of 4 rating on PM.

According to my notes, Yellow Transparent is moderately resistant to PM (see here), but yet it appears to be the case.

This 5-1 tree was actually planted 3 years ago (before I knew anything about fruit) in the back yard where it only got about 50-60% light, so it really didnÂt grow too much. This year, just before it woke up I transplanted it to the front yard (not in my new official orchard, but on the other side of the driveway). Other than the PM, it seems quite happy. It has plenty of new growth already, and has bloomed on 4 out of the 5 branches, but I wonder if it was Âshocked into bloomingÂ. As much as it will hurt to remove the fruit, I know itÂs the right thing to do. Thankfully I have a couple other trees which will produce some.

Last year I saw the same thing (PM) happen to my new Espaliered Liberty. I was surprised because of LibertyÂs disease resistant qualities, but wondered if it picked it up in the nursery where it was grown. Anyway, by the time I obtained the Immunox, the treeÂs PM had advanced further than this. This year, that tree is on the Immunox side of my Ferbam Immunox experiment, and it is showing no signs of PM. I wanted to spray it this year for PM just in case there was any PM overwintering from last year (not positive if thatÂs possible). Next year, it wonÂt get any fungicides (like my other Liberty and disease resistant trees), and IÂd only spray it to put the breaks on something like this.

Anyway, IÂll closely inspect my other trees again tomorrow, and then whack it with the Immunox. I wonÂt be able to use that tree for my Ferbam/Immunox comparison data, but OÂwell. Even if we were wrong here, the Immunox certainly will do no harm.

Thank you and everyone again for their opinions/help.

-Glenn

If you want to avoid other fungicides for your comparison, I've read (and will be trying it out this year) several research papers that suggest that bicarbonates (including sodium bicarbonate -- baking soda) can kill powdery mildew on contact. If I recall correctly, the ratio is generally 0.5% to 1% sodium bicarbonate in water. 2% is reportedly damaging to leaves. It needs to be reapplied weekly.

I've already done some leaf spray tests on my melons and squash with a 1% solution, and they tolerated it just fine. So, this summer I'll find out whether it really works to control the disease.

Hi Karen-
Too late. Already sprayed it this morning. Let us know how the baking soda works out!
-Glenn

Glenn: By all means in the future, submit a sample to your state plant pathology lab, they will give you a definitive answer.

Michael

Hi Michael-
I hadn't even thought of that. Good idea. Is that usually expensive? My 5 minutes of Googling didn't turn up anything, but I probably contact the plant pathology department at University of Rhode Island which is right down the road. Thanks!
-Glenn