Papaya Tree Leaves Gone Bad (#2)

I tried this question in the Tropical Fruits Forum about a month ago.

http://davesgarden.com/community/forums/t/789765/

Folks there were interested, and helpful, but couldn't resolve the question. Perhaps someone here will be familiar with this problem(?)

About two months ago the leaves on one of my papaya trees started coming in very disfigured, and very much smaller. (See image attached) Now I notice that the problem has spread to another tree.

Upon close inspection, I find no evidence of insects whatsoever; and in fact have sprayed with insecticide anyway, as well as fungicide.

Does anyone have any ideas?

Thank you very much,
~~zapatero

Aloha zapatero, welcome.
I haven't seen this problem on my papaya, but I wonder if it could be broad mites? I have had a couple of brugmansia with broad mites which typically shows itself with small distorted leaves, usually slightly downward cupping, attacking the new leaves. Broad mites are microscopic and cannot be seen with the naked eye. Common insecticides do not seem to work on broad mites, at least I have not been able to find one...I remove all the infected leaves off and destroy them, and pray. Broad mites can be killed (so I am told) by a hot water bath (110 for 15 minutes) but of course that is impossible in your situation.
Sorry I cannot be of any real help, do you have a dept of agriculture in Thailand that would be able to identify the problem? I feel for you, especially as it is spreading. I don't think it is one of the common virus.
Perhaps others who are more knowledgeable will chime in.

The deformation leads me to ask you if you are fertilzing the plant with any particular thing?
I've not seen that sort of fungus on my papayas before, but I have seen deformation after using hasta grow, or seaweed based fertilzer. I would remove the leaf just in case.
Rj

Papaya mosaic potexvirus

Carica papaya - systemic vein-clearing and downward curling of leaves, then mottle or mosaic.

Transmitted by means not involving a vector (mechanical innoculation.)

I went to a higher power for an opinion on this one! This is one of the best resources for diagnosing plant viruses:
http://www.agdia.com/

Good luck!

Might be due to virus. It widely spreads in Thailand. Please check this link.
http://www2.dpi.qld.gov.au/horticulture/5333.html

Thank you all for your kind replies. I will try to respond to each:

Braveheart: Other plant people here have suggested the possibility of broad mites, however I have put the leaves under 20x magnification and have found nothing that I would recognize as a mite. But please see below.

rjudd: Good thinking! However, I've used no fertilizers. And the fungicides and insecticides that I have used have had no similar effect on the other plants...

fauna4: I followed your Agdia link and explored around in there. I found both your "mosaic" as well as "ringspot", however was unable to locate any pictures. But you set me onto the virus track, which I hadn't thought of. With a little searching of Google Images, I was able to duplicate the leaf pattern. Based upon those pictures, I now believe that it is PRSV potyvirus. Here is the link, if you are interested:

http://www.padil.gov.au/viewPestDiagnosticImages.aspx?id=399

I spent some time poking around in the PaDIL (Plants and Diseases Image Library) site, and was pretty impressed. If I can contribute something back to the group, here is their Home link. (Pretty obvious from the above, I guess):

http://www.padil.gov.au/

As to my own course of action, I need to digest these findings for a while; but I expect that my response is going to be, regrettably, to destroy the trees. Too bad -- I liked them...

Thank you all, again, for your interest and assistance!
~~z

kukiat: I just now received notice of your response, while I was typing. Thank you! I will follow your link after this post...

This message was edited Dec 13, 2007 11:02 PM

You guys are so smart! Well done!
Good luck, Z, do come back to visit us, you can see there is a wealth of info among "our guys"

Hey Z. I should have posted a link to a site with pictures, but my brain is more on the diagnostic laboratory wavelength. I agree with destroying the plants. There are no cures for viruses, and the only real management practice is to destroy the plants to prevent spread to future plants. Sorry this happened to your plants.

Thanks for that website PaDIL - Pests and Diseases Image Library..that will definately come in handy!

It looks exactly like 2,4-D herbicide damage to me.

I am no expert on papayas but is this the same mosaic disease that put a lot of papaya growers out of business for a while? That is the reason many are now growing the new genetically changed papayas that do no get the disease. Aloha

My papayas have this precise problem too. I sprayed them with F10. Has anyone tried that? Can coddling save the ones who don't have it too badly or is it totally lethal?
Thanks for being there!
Ila