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Grape disease diagnostic

Grape    Syria

Hello,
I am a new grape farmer, And I need help to diagnose my grape disease, The following symptoms are visible, it is bunch closure time in our region,:
Stunted growth, short shoots compared to healthy vines and smaller leaves
Chlorotic leaves
Some fan shaped leaves(i might be mistaken) and some cupped leaves
Cracked berries ,
Red to Purple color on the cracks
Brown mildew like infection on berry skin
Brown mildew on shoot base
I posted pictures of the symptoms, i hope you can advise me if it is one or multipple diseases and what are they?
This might be not a disease and caused by birds or other natural events, please advise me
Best regards


Posted by: youssef al ghadban (1 point) youssef al ghadban
Posted: June 21, 2018


Wendy McFadden-Smith commented,
Images A and B are herbicide injury of some sort. What herbicides were applied in the vineyard? Necrotic spots in C could be spray burn or a leafminer insect. If the latter, you should be able to see the larva inside the lesion if you hold it up to the light. E does not look like mildew, it might be thrips injury. The fungus on shoot just looks normal to me but maybe thrips? I have no idea about the berry splitting but if there is a lot of herbicide drift or other injury to the berries when they are small, as they start to grow near harvest, they may split along the injuries. Sorry I can't be more help with the last bit.
7 months ago.

youssef al ghadban commented,
Hello,
Thank you for your help I appreciate it.
All the leaves on the vine are small comapared with others healthy vines,
The shoots are also very short,
most of the leaves looks normal but small,
and some of them look like the ones shown in Images A and B.
Could herbicide damage have such symptoms?

7 months ago.

David Hughes commented,
Has anyone used herbicide near these grapes? Also, do you see an increase of decrease in symptoms?
7 months ago.

youssef al ghadban commented,
Hello David,
glyphosphate herbicide was used in the field,
only few leaves are showing the symptoms of images A and B.
The rest of the leaves are very small in size compared with healthy vines.
other symptoms are small, stunted shoots.
There is no increase nor decrease in the symptoms.
Awaiting for your reply.


7 months ago.

David Hughes commented,
Where are the healthy vines? In the same field? Go through your vineyard counting how many vines (if possible) and how many have small leaves. Do you see only small leaves on a few vines? Are they close to each other?

7 months ago.



Answers

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Dear grape grower,

I shared the pictures with Penn State grape pest and disease experts, Bryan Hed and Andy Muza. Here our answers.
Please note that without any background information or more pictures, these are guesses at best.

A and B: Looks like a growth regulator type herbicide injury. Characteristic of 2,4-D injury that we see here in the USA. However, certain viruses can also cause leaf distortions that are similar.

C: Not sure if this is disease or not. Doesn’t look like anything we are familiar with. It appears that some lesions have fallen out (?) to give a shot-hole appearance; could be contact herbicide damage?

D: Cracked berries: Hail damage is our first guess. The leaves look a little ragged too, which would lend evidence to hail/weather damage. However, you said there were not caused by natural events.

E: The brown scarring at the base of the first internode could be mite damage. Grape rust mites can cause scarring at shoot bases, cause short shoots with a zig-zag growth pattern. Mite infestation would fit in with a relatively dry climate like that I would expect in Syria.


Posted by: Michela Centinari (2 points) Michela Centinari
Posted: June 28, 2018


youssef al ghadban commented,
Hello,
Thank you for your help I really appreciate it.
Maybe I was not clear in the quetion but it could be because of natural causes, As I was away from the farm Hail did happen and this is the cause of injury.
In Image E (the berries image) there is a brown like scarring on the skin of the berry at the end of the cluster.Is this a mite damage or sun damage or mildew?
In addition, all the leaves on the vine are small comapared with others healthy vines,
The shoots are also very short,
most of the leaves looks normal but small,
and some of them look like the ones shown in Images A and B.
Could herbicide damage have all these symptoms? or is it something else?

7 months ago.

David Hughes commented,
The hail could be responsible for causing damage and then you have secondary growth of a microbe. The question is still the same. Are you seeing the symptoms spread?
7 months ago.

Michela Centinari commented,
Herbicide damage can cause different type of symptoms. Affected vines might have short shoots (shorter than average), stunted growth without showing the distorted leaves. Damage can also affect the flowers/fruit.
7 months ago.



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