avocado mineral deficency (forum)

nick starts with ...
Hi looking for a opinion on a suspected mineral deficency on a grafted wurtz advocado about 3 years old 2.5m high, soil is sandy/loam ph appears normal maybe a touch towards acid,rainfall/moisture is not a issue,no frosts, it produced plenty of flowers/fruit but all dropped i suspect its still establishing itself i have lightly fertilized with wormjuice/seaweed solution and chicken poo pellets,would appreciate some advice.
Pictures - Click to enlarge

Picture: 1
Picture: 2

Time: 4th January 2012 1:19pm

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About the Author nick9
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amanda says...
Nick - is it the older leaves, young leaves (or - all over) that are like this?
I don't know what avo's are typically fussy about (maybe Brendan, Jason etc..?)


Time: 5th January 2012 12:08pm

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About the Author amanda19
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Jason says...
HI Nick, that's an interesting leaf, I haven't seen any like that myself here. When mine are lacking they just go a more uniform pale colour and they only need nitrogen to fix it. But the good news is you don't seem to have a mineral deficiency so I'd just sprinkle around some general NPK fertiliser for evergreen fruit tree with about 20% nitrogen. Worm juice and chicken poo generally isn't strong enough for a tree like an Avocado

Time: 5th January 2012 2:39pm

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About the Author Jason
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Mike says...
It looks like the green veins with yellow between are symptoms of Mg,Fe or Zn defiency.Fe and Zn defiency usually results in small leaves with Mg and Fe defiency often accompanied by down curled leaves.If it is not purely from poor soil applying to much calcium in products like gypsum or too much phosphorous may have an antagonistic influence on the availability of the micronutrients mentioned.The natural fertilisers you mention may be stacked towards N and not have enough micros.Foliar applications with all micros should help.

Time: 5th January 2012 3:34pm

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nick says...
thanks for all your response guys, i forgot to add the tree had dead/burnt leaf tips prior to flowering also we have had a lot of rain for the last 3 months and apart from new growth 65percent of the tree has affected leaves as shown in the photos

Time: 5th January 2012 10:40pm

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About the Author nick5
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amanda says...
It can be really hard to tell the difference with a deficiency - even more so when then are 2 (or more) at play...

If the new leaves are much smaller, if the vein pattern is confined to a leaf class (young or old) etc...all matters.

Not saying this is your problem at all - but sometimes deficiency can even be transient (eg- I get an iron deficeincy thru over watering on sandy loam - even tho' my pH is normal - it just leaches too easily - and as soon as the weather dries up - it's not a problem anymore)

In times of real doubt I choose trace elements and a nitrogen fix (as Jason mentions)

Not sure about the burnt margins - maybe chook pellets are not a good choice for avo's where u are - apparently they are high in salts? (like chook poo) and avo's hate salt.

Not sure there - but when in doubt I go for blood n bone now...much safer for fussy trees..

Time: 6th January 2012 12:00am

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Original Post was last edited: 6th January 2012 12:02am

About the Author amanda19
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Brendan says...
Hi nick, I asked the garden guru here about your avocado, and here's his reply:
"This is Zinc deficiency, apply Zinc and Manganese under the canopy spread one clenched handful per sq metre, this is available from Garden centres in 500gram packs. To displace any salts apply Gypsum, four clenched handfuls per sq metre, it will be a salt causing the tips to burn."

Hope that helps.

Time: 9th January 2012 8:24am

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Original Post was last edited: 9th January 2012 8:25am

About the Author Brendan
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Jason says...
You get burnt tips on older leaves on Avocados with magnesium deficiency, it looks nothing like that picture and is pretty common, almost standard on Avocados around here since the soil in Australia has next to no magnesium, probably the main reason Australians are so unhealthy compared to Europeans. I guess zinc might do something to younger leaves

Time: 9th January 2012 7:31pm

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Original Post was last edited: 9th January 2012 7:32pm

About the Author Jason
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amanda says...
Umm...my sand has the right levels of magnesium Jason..? :) Isn't Sydney sandstone country? I know limestone is a pain to grow on - whats sandstone like? (just curious here..)

I was thinking the same as Mike, Mn, Zinc or Iron - nick what is the size comparison between one of your oldest leaves compared to a recently matured leaf?

I'd go for trace elements too...it would be nice to check the response for for both iron chelates and the Zn/Mn separately tho...then u could target it specifically in your fertilising regime.

My pH is normal and my citrus trees still need the Fe/Zn/Mn combo...none of my other trees have this problem - only my citrus (and most severely - my lemon and limes..) it's just the way they are..?



Time: 10th January 2012 10:29am

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Original Post was last edited: 10th January 2012 10:30am

About the Author amanda19
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Jason says...
My soil is acid and surprisingly my Citrus don't need anything other than the odd dose of nitrogen to be perfectly happy, just about ever other plant seems to want much more fertiliser added than the citrus

Time: 10th January 2012 7:40pm

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About the Author Jason
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nick says...
thanks for all the info guys ,Amanda all the leaves on the avo appear normal in size its putting out alot of new growth,im on the coast fairly protected from wind but we do get a lot of rain/coastal showers average 1000/1400 mm annually ive given the tree small amounts of magnesium/zinc old chook poo and blood and bone all bases covered will keep you posted

Time: 10th January 2012 10:17pm

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amanda says...
Jason...I am beginning to think that citrus prefer more acid myself...? My orchard citrus are really different to my 'free range' ones - they get the recycled water from our Biolytix (total waste water - black also) and they only need nitrogen too...the soil in my orchard is slightly more acid because of the Biolytix...

Out in the open (non-Biolytix) they all complain of the same problem...Zn/Mn/Fe.

I think it's really interesting myself - the difference between a pH of 6 and 7 can be a lot for some plants it seems..? It's strange that it's more pronounced with my lemons and limes (4 types)compared with my tangello, mandarins, oranges and grapefruit...? (so I suspect the rootstock has influence too perhaps?)

Nicks tree is most certainly lacking a trace element - I would be really interested to see what a foliar spray of chelated iron does...?

Here is a very basic link on Sydney sandstone (don't know what nick has - but the info here was interesting anyway!?)

http://www.abc.net.au/gardening/stories/s2954298.htm



Time: 10th January 2012 11:30pm

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About the Author amanda19
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Brendan says...
Hi nick, Jason,
The zinc & manganese was to fix the motley leaves in the top photos. Nick added later he had some leaf tip burn, that's what the gypsum was for :-)
I have never heard of a lack of magnesium causing leaf tip burn on avocado trees? I'm not saying you're wrong, I've never heard it before.
I've 'fixed' a few avocado trees that had leaf tip burn with extra phosphorus.

Time: 11th January 2012 8:12am

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About the Author Brendan
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amanda says...
yea - I think we all agree it's not magnesium...I'd be giving it a load of good manure (cow,pig or sheep) to fix. It will breakdown more slowly in the rainfall and provide the trace elements in a more friendly form.
Lots of organic matter = better pH buffering and less of these trace element problems....

Time: 12th January 2012 10:00am

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