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- 08-06-2012, 12:46 PM #1Germinator
- Join Date
- Sep 2011
Black Spots on Apples???
I have got a small apple tree (it is a grafted one with two varieties) and some (not all) the apples have got small black spots on them. I've attached a picture. They aren't pitted or rough, in fact, they feel the same as the rest of the apple. Do you know what it is and what can be done to avoid it getting to the rest of the apples? I've picked off the ones with the black spots (hopefully the right thing to do) as there were plenty of apples on the tree anyway so when I thinned them out I made sure any with black spots were the first to go.
- 08-06-2012, 01:58 PM #2
Dunno really, but googled it and found this:
Black Spot on Apples and Pears - Hortwatch Library
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- 08-06-2012, 03:01 PM #3Germinator
- Join Date
- Sep 2011
I sprayed it with fungicide anyway. The leaves don't have the patches for apple scab / black spot. They look quite healthy. Let's hope the fungicide combined with picking off the spotty apples will help.
- 08-06-2012, 03:10 PM #4
They don't look like apples, just the little unfertilised ones that fall off anyway. Its June drop time too so your tree may be dumping some of its own accord.
I'm sure someone who knows what they're talking about will be along soon -( no offence intended PnKNutty and Norty
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- 08-06-2012, 03:45 PM #5
It is always tremendously helpful to know someone's location when giving advice.
My guess is that it's scab - a combination of wet weather and a variety which doesn't have sufficicent resistance (i.e. a fairly common variety), or a specific apple variety which is grown in large numbers in your area (hence there has been a long-term build-up of diseases which have had plenty of time to find ways round a tree's resistance).
Infections which are already present won't be cured. It is likely that the brown (dead) bits will not grow properly as the apples get bigger which often results in the skin splitting and the fruit rotting on the tree..
- 08-06-2012, 03:56 PM #6
Here's a link to a nice picture of what can happen:
BEV1595- APPLE FRUIT SPLIT ON APPLE : Asset Details -Garden World Images
As I said: once infected the brown bit is already dead and wll not grow properly (hence splitting).
On very susceptible varieties, fungicide (<shudder>) needs to be applied immediately after any period of several hours of rain.
The link provided by PnQ above gives a nice table of wet period v temperature. Periods which coudl result in scab infection are also known as "Mills periods".
A more detailed Mills table here, which shows that symptoms appear a couple of weeks after infection has occured:
- 08-06-2012, 09:12 PM #7Germinator
- Join Date
- Sep 2011
I have gotten rid of all the ones with spots on so I'm hoping the rest will be ok. I shall have to take my chances and see what happens now.
- 08-06-2012, 09:54 PM #8
Well wherever it came from, it'll probably come back from in the future. The spores may also be scattered around the tree from rain splash and fallen leaves.
Along with not mentioning location, you haven't mentioned the variety which you're growing.
These could have a large influence on whether it's likely to be transient for this wet year only, or whether you're building epidemic proportions of attack for subsequent years.
The problem with spraying against scab, is that the fungicide also kills "good fungi" which expose the tree to other attacks from other fungi (which the "good fungi" would normally outcompete and drive-out). So once spraying routines have begun, if can become a vicious circle - otherwise the consequence is a very diseased tree for a few years after spraying is stopped, until the "good fungi" find their way back to it (carried by wind or rain splash).
It is quite common for newly planted trees to suffer from diseases because they were sprayed at the nursery from which they came (and, of course, the nursery was an ideal breeding ground for diseases with large numbers of trees crowded together).
Of course, some trees - the well-known varieties you find in the supermarkets or farm shops - are often quite very prone to diseases; especially scab.
For curiosity: I have a lot of rare varieties and despite the unprecedented heavy rain we've seen (barely a day without rain for three months and we've already had about two years worth of rain so far this year!), yet the rare varieties have no fruit scab at all, and only minor leaf scab which I can only find on the odd leaf, if I look very closely. Quite impressive.
On the other hand, my James Grieve and Egremont Russet (two fairly common varieties) have both died from an overwhelming attack of canker, the likes of which I've never seen or heard of.
Last edited by FB.; 08-06-2012 at 10:02 PM..
- 09-06-2012, 01:42 AM #9
Now you're making me nervous about my two new apple trees that are not yet planted. Off to do a search on here to find out what my worst problems are likely to be.Ali
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- 09-06-2012, 05:51 AM #10