[hereistay]

Two weeks ago I bought 45 plants of Pistacia Terebinthus.
These have 2-4 years and are inside a 9x5 alveolar polystyrene tray.
The seller told me to put them outside and to humidify the soil.
I live in Center Italy, at the same latitude of Rome but on the Adriatic coast, at about 10km from the sea with an altitude od about 200m slm.
Here in Abruzzo Pistacia Terebinthus grows spontaneous on mountains, and at an altitude of about 600m slm.
These plants come from southern Italy where the temperaturea are higher than here but they have been cultured at 1000m slm, so the temperature is not a problem I think.
When the plants arrived, leaves were yellowing and there were black spots on leaves.
Now, after two weeks, a lot of leaves have dried and it doesn't seems to be due to fall season.
This is a deciduous plant, so it is normal loosing leaves at this time, but there are these spots and i want to understand what it is!
I can add that the first 10 days I put the plants inside a big agricultural greenhouse because temperatures seemed to have lowered and it was raining but this week temperatures raised so I asked the seller and I decided to put them outside.
What is strange, according to me, is that the seller told me to water twice a week, because I read that this plant suffers of root rot and can live on rocks without water for a long time!
So, by watching these photos, are you able to tell me what these spots are?

[David Bracey]

It looks very much like Septoria leaf spot. 

[Alisdair]

Septoria pistaciae commonly affects deciduous Pistacias around the Mediterranean and elsewhere. Trials in the 1990s in commercial pictachio orchards in Arizona found that common fungicides including Benlate did control the spotting, so much so in fact that while in untreated trees the leaves around nut clusters had died off by harvest those in treated trees were still alive. (But the trial plots were too small to show whether this improved the actual harvest yield.)
I doubt if it's worth bothering to spray your plants, unless you find the spotting really disfiguring.

[hereistay]

Ok...
So if it is Septoria, have I to remove leaves or to prune?
I would to spray cupric because I read that next spring the disease may occur again and my goal is to let them grow to graft with Pistacia Vera from next year, so I want vigorous plants.
Now I'm going to put about 30 plants inside phyto bags (the black plastic bags for plants) and I'll leave them there and I'll try to graft while they are inside bags.
I want to  plant in orchard the remaining 25 plants and try to graft them in the coming years.
According to you have I to plant now or is better to wait next spring?

[David Bracey]

Your questions are not straight forward.  Frankly with this level of infestation I suggest that you ask your supplier for clean material.  Is P. vera susceptible to disease?  I would cut back as hard as you can to an obvious bud, collect all the clippings and fallen leaves and burn.

Move these plants to a clean area.  Spray now with benlate, copper or any general fungicide and again in two weeks.  Start to spray in the spring as soon as fresh growth appears.

Probably it is better to plant now..... assuming you have confidence that the shortened plants will establish and grow.Perhaps you should ask the supplier for his advice----after all he should be the expert.

[hereistay]

The supplier told me to plant now in orchard or to leave inside the polystirene tray until next spring!
Today I removed the dried leaves and tomorrow I'm going to put about 20 plants inside plant bags and to spray a cupric fungicide.
I'm going to spray cupric sulphate g.10 (=124 g/l) in a ratio of 16ml/l.

[hereistay]

Today I moved the plants to plant bags, now i have 20 plants in plant bags, 3 plants in pots and 22 plants in the polystirene tray, so they have more space than before!
About the treatment for Septoria, someone told me to use triazole fungicide, because a cupric one is ineffective, but someone told me if these plants will survive after this treatment because they are too little!
What do you think about it?A fungicide treatment will kill them?
I thought also to put some straw on the top of the bags to defend from cold, what do you think about it?It's a good idea?
In general it's a good idea to leave these plants outside?

Here some photos:

Plants in plant bags (23):



Plants in tray (22):



I placed the plants on a old house terrace south-facing, as you can see in the photo below.
Do you think is a good place?
Have I to build a shelter from rain?

[David Bracey]

The literature is not very good however it seems that all the Pistacia spp are equally susceptible to Septoria.  The modern fungicides based on strobulirins give the best control however most broadspectrum fungicides seem to work satistactorily.  It really depends on what is available on the market.  Two sprays in the 3 Quarter seem to give best control but clearly you need to find out the local recommendations. 

triazoles will do a good job.

[hereistay]

Somenone told me that fungicides based on strobulirins doesn't work at low temperatures...
So you mean strobulirins works good from July to September?
Anyhow now I'm not going to spray any fungicide because the leaves are falling and the incoming low temperature should stop the fungus.
I'm going to spray some penconazole at new growth in february-march!

[David Bracey]

Penconazole is a broad spectrum triazole. I think you should spray now to try to reduce the innoculum that is building up in your plastic house.  Clean up the fallen leaves as well. 

[hereistay]

Plastic house?
The plants are outside...
Anyhow, do you think that sprying fungicide will kill these little plants?
And...what ratio have I to prepare to spray?On the label there is no ml/l quantity for pistacia terebinthus of course!

[David Bracey]

A spray now will not hurt your plants. I cannot tell you what dose to use unless know the concentration of the product. .

[hereistay]

I don't know if I can write the brand of the product...on the label is written:

Active Ingredient in 100g of product: 19g (200 g/litre) PENCONAZOLE in the form of an oil in water emulsion.

Also contains: 139 g/litre hydrocarbon liquids, 1,2-benzisothiazolin-3-one.

For the control of Powdery Mildew in Grapes, Cucurbits, Peas and Apples and
Blackspot in Apples and Pears.


I have a question.
In a italian gardening forum, some members told me not to give fungicide because leaves are falling and low temperatures will stop the fungus.
Is it a good idea?
If I avoid the leaves to touch the soil, next spring Septoria will reveal again?
Is it true that winter low temperatures will kill Septoria fungus?

[David Bracey]

Is you product aliquid of powder??  Not clear

[hereistay]

It is liquid!