By Balcony
Cambs,
United Kingdom 
Yellow Crookneck Squash (Possible virus infection?)
This is the first time I’ve ever grown these squashes. The seeds were sent to me by my sister who lives in Texas, USA. They were sown in the greenhouse on the allotment & a few weeks later transplanted to a bed at the top of Gerry’s plot.
That had been looking alright till these past couple of weeks. Now two of the plants have developed what looks like a virus infection & their fruit (at least on the only plant that has fruit at present) is mottled yellow & green – as can be seen in the photo. The leaves are quite different from those plants that are not showing any symptoms of having a viral infection.
My question then is: What is wrong with these plants? If it is confirmed as a virus, should I destroy the plants? Will it be transmitted to the healthy plants & will it be transmitted to the Zuchinnis/Courgettes they share the bed with? Could it be transmitted to Pumpkins? What about Cucumbers? I have all 4 growing in different areas of the allotment.
20 Aug, 2013
Answers
You say that the seeds were sent to you from USA - was it a retail pack of seeds or seeds from your sister's own crop?
The reason I ask is that there are restrictions on the importation of plants and plant products. These plants are obviously infected with something - could be a UK/home grown disease but equally it could have been imported with the seed.
It may seem that it was a nice thing for your sister to send you some seeds but you might want to consider some of the diseases that spread on contaminated plant material - ash die-back, potato blight....
Check out the DEFRA page https://www.gov.uk/personal-food-plant-and-animal-product-imports - 'Plants' are about 3/4 of the way down.
21 Aug, 2013
p.s.: re my answer above, I've just looked on Google and found the link below, re "'cucumber' mosaic virus" which may help (and alas, dismay!) you:
http://apps.rhs.org.uk/advicesearch/profile.aspx?pid=143
21 Aug, 2013
Urbanite: Thanks for the link. The seeds were commercial seeds as my sister doesn't grow anything that I'm aware of! :-((
Monjardinlra: Thanks also for your link.
Even though I'd never seen it I was right then in my own suspicions! I thought it looked like a virus infection! Now I wish I'd destroyed the when I noticed them the first time!
I asked the same question on another gardening forum which is even more international than this site but I haven't received any replies yet. :-((
27 Aug, 2013
I destroyed the plants as soon as I went down to the plot a couple of days ago. I don't want the rest of my plants to become infected. They seem to be OK for the moment & the virus doesn't seem to have spread to my Pumpkins or to the cucumbers in the greenhouse.
29 Aug, 2013
Previous question
I've never grown this particular squash, but we used to get something very similar sometimes in my garden in Norfolk on courgettes (distorted leaves and mottled fruit). It was called Mosaic Virus.
In those days (20 yrs ago) the advice used to be: yes, it can infect other things of the same family (e.g. cucumbers, pumpkins and others such as aubergines) and there wasn't a treatment other than rapidly removing and disposing of infected plants, alas! I think it is spread by insects so I should think others of your plants might be at risk but maybe there is a treatment nowadays? (check further before destroying!)
21 Aug, 2013