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Newcastle, CA

One of my plants has the virus that the mad scientists shows in one of his pictures under leaf problems. The leaves are light green with dark green raised spots. It says there no cure and yes I have aphid problems. The questions is do I let the plant keep going or pull it out? It does have a kin growing on it. Will it spread to the other plants? Should I move the leaves that show signs of the virus or will they still help feed the growing kin?

7/28/2013 10:10:00 PM

Connecticut

Hi Newcastle:

The main question is how old is the pumpkin?

If 20+days old it can grow to be 1,000+ pounds

If under 20-days old it may develop structural issues leading to a problem later in the season.

I have had first hand experience with virus infected plants and I can say that yes it will most likely transmit to other plants in the patch (if it has not done so already). Removing the infected leaves will not do much as the virus is already running through the entire plant. While the efficiency may be down the leaves will still be able to produce some energy for your pumpkin.

Look at my 2012 diary (in particular June 23rd-August 21st): http://www.bigpumpkins.com/Diary/DiaryView.asp?season=2012&grower=25411&action=L

I do know of a grower that was able to get a pumpkin over 1,000lb with two types of virus ID in their plants.

Personally, I do suggest you get a virus screen so you know what virus (or viruses) you may have. This will not help you this year but it will tell you the odds of residual your patch may have. For example, Zucchini Yellow Mosaic as a low residual and in contrast Tobacco Mosaic has a 20+year residual.

Also, it seems virus infected plants may produce pumpkins with shortened shelf life, but my sample size to show this is very small so the pattern could be inaccurate.

-Mad Scientist Matt D.;-)

7/28/2013 11:31:50 PM

Citrus Heights, CA

Tom, Give me a call and I can expand on what Matt said. Ron

7/29/2013 12:35:08 AM

Newcastle, CA

Thanks Matt and Ron, I think I will let it play out. I did post a picture of a leaf I am not sure I will have the resources to get it ID'd:

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=205378

I will measure the pumpkin after work. It is not that big I am not sure how old, maybe about two weeks... I need to work on keeping better records. First year, live and learn... Thanks Ron for your time on the phone.

7/29/2013 4:35:30 PM

Oak Grove, Mn

interesting...how does a grower get a virus screen?

7/30/2013 12:04:03 AM

Citrus Heights, CA

Send a sample of the plant to a lab, short time later you get the result's.

7/30/2013 1:47:12 AM

Connecticut

Here is the lab I used. I thought they were very good at doing the crop screen and getting the results back to me. You can see in the link the common 13 and then below that you can add any number of the other virus screens for a small fee per each one you add.

It is very hard to ID a virus from just a picture, but to me it looks like you may have Watermelon Mosic so if you wanted to do the screen I would highly recommend you add this one to the list to have the lab screen for.

Link:
http://www.agdia.com/testing-services/Cucurbit-Cucumber--Melon.cfm

7/31/2013 12:58:11 AM

Newcastle, CA

I noticed the virus has spread to a couple of the field pumpkins. I hope I can get some fruit set. Trying to control the bugs the best I can. I can add this to the list for next year. I will send to a lab tomorrow. I added to my diary pictures of some fruit from the infected plant. The one large kin is still doing fine and shows no abnormalities.

Question, can I grow here next year? Does the virus stick around in the ground? Is it spread strictly by insects? Lets say it was watermelon mosaic do I need to rest this area a few seasons? After I get my lab results back I will post here the findings.

http://bigpumpkins.com/Diary/DiaryViewOne.asp?eid=205567

7/31/2013 2:12:17 PM

Connecticut

Insecticides do not help in prevention as none of them work fast enough. An infected aphid needs to only stick the leaf to transmit the virus which can take under 5sec. to spread the virus. I can die or leave after this and it is already to late for the plant.

My guess is you will have a difficult time setting a fruit as last year I had one pumpkin that was 20days old and while the plant became infected the pumpkin did not show visible signs of infection. This lead to my theory that pumpkins do not divide their cells after day 20. After do some scientific research there is some evidence that supports this theory in other crops. I am still not sure how to best utilize this but this is a major discovery in determine when and how to push future production, in my opinion.

To get toy your specific questions...

-Can I grow here next year? Depends what virus you have. Tobacco Moais (TMV has probably one of the longest residuals which is near 20+years!)

-Does the virus stick around in the soil? Depends which one you have;-) I also did a dagger nematode screen as the virus can winter over in these hosts which can then infect your plants the following year.

-How is it spread? Typically initially by insects to get it to the patch, then through mechanical transport either by you the grower or even as simple as two leaves touching one another.

-Lets say, XYZ... I would not worry about coming up the the 1,000+ different possible situations wait for the results and focus on what they say to develop a plan from there.

-Please send me the results and/or post them on bigpumpkins.com I can help you develop a plan once we have some data.

***There is still hope for next year as so far I have not seen virus in my patch even though I lost the entire crop last year to ZYMV (Zucchini Yellow Mosaic Virus).

7/31/2013 11:41:40 PM

President - GPC

@Matt... Do you think thatZ a cover crop of mustardZ would benefit the fumagation? Especially from the nematodeZ end...??

8/1/2013 10:03:14 AM

Connecticut

There are some cover crops that have anti-nematode properties, but in the case of a known virus infection I would want to preform the screen before adding any products or cover crops.

Also, as in many cases there are actually good nematodes so the reason why I would target the identification of the daggers is they are the specific ones that can carry over viruses. The goal is to focus resources to a specific problem so a plan that had the highest odds of being effective can be reached.

8/1/2013 5:08:20 PM

Newcastle, CA

Received an email from Agdia Inc.

"We have completed the initial ELISA testing of your samples and found your Pumpkin leaf sample to test positive for WMV and POTY. I hope to get a final report to you soon."

WMV = Watermelon mosaic virus
POTY = Potyvirus group test

I will post the final results once I get them.

8/5/2013 12:26:09 AM

Newcastle, CA

Here is the official results:

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=206063

Tested positive for Watermelon mosaic virus, potyvirus group and elevated results for Zucchini yellow mosaic virus.

Matt any info on residual for next year?

8/5/2013 7:35:40 PM