Asimina triloba (pawpaw) with spots: what is it?
General None Given
Hello everyone!
I'm from center Italy and I have two Asimina Triloba (aka PawPaw) planted the last winter.
One of them has been damaged by snails the other has some snails damages but has also some spots and burned pieces.
According to you what can it be?
Thank you!
I'm from center Italy and I have two Asimina Triloba (aka PawPaw) planted the last winter.
One of them has been damaged by snails the other has some snails damages but has also some spots and burned pieces.
According to you what can it be?
Thank you!
Posted
by: Mirko
(2 points)
Posted: July 6, 2016
Answers
I think the spots of your pawpaw leaves may be due to sunburn or fungal leaf spot caused by Phyllosticta asiminae.
Generally the spots caused by Phyllosticta are tan circular or irregular with dark brown borders on leaves (the center of spot become pale and bleached as disease advances). Also this spots may merge and appear bigger at later stage. Fruits may also develop dark brown to black superficial spots.
Sunburn leaves shows browning of leaf margins and/or yellowing and darkening of the areas between the main leaf veins. It happens due to prolonged periods of dry, windy weather or bright sunshine.
To know the exact reason it is important to use a microscope and look for Pathogen. Do you have University or Agriculture experiment Stations near by? If it is Phyllosticta you will see conidia (asexual spores) on this spots. Please see the attached images for your reference.
Generally the spots caused by Phyllosticta are tan circular or irregular with dark brown borders on leaves (the center of spot become pale and bleached as disease advances). Also this spots may merge and appear bigger at later stage. Fruits may also develop dark brown to black superficial spots.
Sunburn leaves shows browning of leaf margins and/or yellowing and darkening of the areas between the main leaf veins. It happens due to prolonged periods of dry, windy weather or bright sunshine.
To know the exact reason it is important to use a microscope and look for Pathogen. Do you have University or Agriculture experiment Stations near by? If it is Phyllosticta you will see conidia (asexual spores) on this spots. Please see the attached images for your reference.
Leaf Spots (Phyllosticta) on Pawpaw Tree
Cross section of leaf infected with phyllosticta showing conidia under microscope
Fruit Spots (Phyllosticta) on Pawpaw Fruit
Conidia of Phyllosticta visible under microscope
Posted
by: Dr. Ravishankar Narayana
(15 points)
Posted: July 6, 2016
Mirko commented,
Thank you. The seller (who should be the most experienced in Italy and Europe) told me that these plants have no problems with fungi. Anyway, if I have to cut damaged leaves won't remain a leaf! :D I noticed that it started with a sort of brown stain on the upper surface of the leaf (you can see an example on the bottom right of the leaf in the last pic) and now it is burned. Could it also be a damage due to direct sunlight? I read that Asimina Triloba should be protected from direct sunlight in the first two years. These plants should have at least 3 years but I bought and planted them only the last winter. almost 8 years ago.
Thank you. The seller (who should be the most experienced in Italy and Europe) told me that these plants have no problems with fungi. Anyway, if I have to cut damaged leaves won't remain a leaf! :D I noticed that it started with a sort of brown stain on the upper surface of the leaf (you can see an example on the bottom right of the leaf in the last pic) and now it is burned. Could it also be a damage due to direct sunlight? I read that Asimina Triloba should be protected from direct sunlight in the first two years. These plants should have at least 3 years but I bought and planted them only the last winter. almost 8 years ago.
Dr. Ravishankar Narayana commented,
Yes we contacted our experts and have been told that it may be sunburn. almost 8 years ago.
Yes we contacted our experts and have been told that it may be sunburn. almost 8 years ago.
Mirko commented,
Thank you for your reply! I have another question...can you tell me what kind of fertilizer I can use on asima's plants? The seller told me not to fertilize it because it can kill it but I read that it is possible to fertilize it... almost 8 years ago.
Thank you for your reply! I have another question...can you tell me what kind of fertilizer I can use on asima's plants? The seller told me not to fertilize it because it can kill it but I read that it is possible to fertilize it... almost 8 years ago.
Thank you!
Anyway I cut the most damaged leaves.
I don't know if there is a connection but, near these asimina, there are grape vines cut years before and they have new shoots.
According to me these shoots have black rot and as I read online black rot is connected whit Phyllosticta.
I give you other pics.
Anyway I cut the most damaged leaves.
I don't know if there is a connection but, near these asimina, there are grape vines cut years before and they have new shoots.
According to me these shoots have black rot and as I read online black rot is connected whit Phyllosticta.
I give you other pics.
Posted
by: Mirko
(2 points)
Posted: July 6, 2016
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