Question

Leaf Problem   QUESTION: I have a problem with only one of the four types of potato I am growing in large fabric tubs. I have 2 tubs of each kind. They are lined up right next to one another. One type has started producing small cupped leaves on the new growth, and the flowers look wilted. I cannot see any indication of insects on these branches or discoloration, or fungal growth. And it hasn't spread to the adjacent tub. I looked up potato leaf curl images on the internet and it definitely isn't what I've seen. I am in the western mountains of Virginia and we have had a wild spring - enormous amounts of rain and humid overcast days, a late freeze, and yesterday another 2" of rain in 4 hours accompanied at times by bouts of grape-sized hail. Could this type of potato be more sensitive to the wet conditions than the others? That brings me to the type of potato effected. My 4 year granddaughter helped me plant them and conveniently disconnected the name of the seed potatoes from the actual seed potatoes. I know I have:Red Norland, Red Gold, Yukon Gold, Yellow Finn. Any light you can shine on this problem would be appreciated.

ANSWER: Margaret:
These symptoms of cupping/leaf distortions can most likely be caused by one of two things- (1) a virus infection or (2)contact/uptake of a certain group of herbicides (weed killers). There is no cure for any plant viruses.  This disease can spread to other plants often by some insect.  Review any use of weed killers to these plants, surrounding vegetation, even to the containers. I do not think these symptoms are related to the weather.

Steve

---------- FOLLOW-UP ----------

QUESTION: Steve,
First of all thanks for the holiday reply.
These potato tubs are located against a chickenwire fence that had been sprayed along the ground with Round-Up about two months ago, after the tubs were in place but also after the plants had been mounded up (all leaves covered). Is Round-Up in the group of herbicides that could cause this problem? Even if not applied to plant leaves? I have never used any other herbicide. Will the plant eventually die from this inadvertent application? If not, would it render the potatoes inedible?
If it's a virus, what do I do now? It hasn't visibly spread to any other plants even though they are physically touching. Will it make the potatoes inedible?
Thanks for your help.

Answer
Margaret:
It is my understanding that Roundup (when applied correctly) will not do this distortion stuff. It requires plant contact to cause damage. Roundup can be potent! Always spray this stuff when there is no wind. Some people apply it using a sponge to avoid any potential drift on a breeze. It can kill if it contacts any green tissues.
If it is a virus, there is no cure, no chemical to eradicate it. Many viruses are carried by insects, so insecticides are useful in minimizing infections. Growing resistant varieties, using clean/virus free planting seeds or slips is the best method.  Also keeping weeds controlled adjacent to your growing areas is helpful. I have not heard of any health problems by eating infected plants or plant parts.

Hope this helps. And hope you had a great holiday.  I grilled some burgers on a new grill. I had may previous grill for 22 years.  I almost cried when we gave up the old one ha-ha!!

Steve