started to curl/cup …see attached pictures.
There is more curling on the newer leaves; the older leaves are OK and
the curling is only on one side of the plant.
The Red Flame grapes planted adjacent to the Thompson Seedless grapes
are OK and no sign of curling or cupping.
These 5-gallon plants that I planted 2 years ago. All of the plants are on a dripline system
and are watered three times a week, one hour each time. Each plant has two 1-gallon drippers so each
plant is receiving 6 gallons of water per week … is that sufficient? The plants are in a raised bed approximately
18 inches deep of premium mulch/soil.
Both of the plants have several bunches of grapes and I have already pinched
off the bottom 1/3 of each grape bunch.
Any advice would be appreciated.
 |
| Leaf cupping on grape. Possibly from 2,4-D or a close relative, a phenoxy herbicide known for its effects on regulating growth of plants at very low concentrations but acting like a weed killer at higher doses. |
plants are thriving. Six gallons a week is a bit light in my opinion but watch
the plants and they will tell you. If you are getting some good vigorous growth
from six gallons then it is enough and I would not change it.
Grapes are
normally deep rooted plants and can have roots that go down dozens of feet. In
our landscapes this doesn’t make much sense to water deeply to accommodate
roots like this so your raised bed sounds like a good depth for the plants. You
are watering only to a depth of maybe 18 inches or so, so watering three times
a week right now on grapes with this rooting depth makes sense to me. After
grape harvest, you could cut back on the frequency of your application (times
per week) if you want to but it is not necessary. But you need to maintain good
soil moisture during and up to fruit harvest.
two types of grape thinning; one is removing grape bunches that are too small
and spacing bunches so they are not too close together (8 to 10 inches apart)
AND reducing the bunch by pinching off the bottom third of the bunch. This is
done as early in bunch formation as possible.
skeletonizer, leafhopper or hornworm control so I guess you haven’t seen any.
very often and that is the fleabeetle. They are small, dark blue/black rather
round looking insects that chew holes in the leaves. They are usually not that
devastating so we just ignore them but once in a while they can cause
considerable leaf damage in the spring and fall.
on developing (young) leaves since the cupping results from leaf growth in the
center of the leaf while the leaf edges either don’t grow as fast or are
damaged so don’t grow at all. There are three primary reasons leaf cupping can
occur. First is damage from a chemical growth regulator that drifted on to your
vines.
 |
| Thompson seedless from reader next to affected grapes but no signs of damage. |
Grapes can be quite sensitive to these chemicals. One common growth
regulator used by homeowners for lawn weed control is 2,4-D and sister
compounds that are also growth regulators. Commonly these chemicals are used to
control dandelions and other “broadleaf weeds” in lawns. If this chemical were
applied to a nearby lawn (could even be 100 yards away) and there was a wind
that blew this chemical from the lawn to your grape vine then that would
explain the cupping. This type of damage is usually not deadly but just causes
leaf distortion. The leaves are not just distorted but weirdly distorted. The
leaves will not un-distort or grow back normally. They will be like that until
leaf fall. The fruit is safe to eat.
cupping when they are feeding. The most common insects that do these sorts of
things are aphids. The feeding of aphids on plant leaves that are still growing
can cause the leaves to cup downward (this is called epinasty in horticultural
terms). It is thought that this type of plant reaction to the feeding of aphids
is a protection for these insects from predators. Aphids of course secrete
honeydew, a sugary substance made from the plant juices they suck, which
attracts ants. The ants in turn use the honeydew as a food source and help
protect the aphids from predators in exchange for “harvesting” the honeydew.
Aphids are not common on grapes.
 |
| Aphids feeding on new growth of plum causing the cupping of the leaves due to their feeding on expanding new growth. Aphids are also covering the stems. |
leaning towards. If the leaves were just coming out and expanding and if there
was suddenly a very hot wind OR it got hot quickly and the grapes were tender
enough to get some damage to the leaf edges then this would explain the cupping.
The leaf edge would dry out from high temperatures or a hot wind and dessicate
or dry out. The damaged leaf edge would not be able to grow or grow slowly. The
rest of the leaf would be unaffected and would expand or grow. The growth of
the center of the leaf while the leaf edge remained unable to grow or grow as
fast would begin to cup. The cupping would be worse as it grew more. And of
course this would happen only to young leaves which are still growing or
expanding. Again, all will be well but you should check to make sure the vines
are getting enough water. If they were droughty, the leaf edges would scorch
and cupping would result as well.
two gallon per hour emitters or higher and apply a surface mulch to reduce
water loss from the soil.
Thanks. I too was wondering what was causing leaf cupping on my grapes and some other fruit trees. I knew it wasn't aphids, nor anything else I could see. My neighbor sprays all kinds of herbicide–sigh–but I too go along with it probably being the hot dry winds (Phoenix, AZ).
If anyone is looking for a new cultivar, "Blueberry" grape is really doing well (its second year) here. Better than ANY other grape I have seen. I get flood irrigation every 2 weeks and have mine on the west side of a block fence wall UP on the irrigation berm (raised). I have not watered it at ALL this year other than what it gets from the irrigation and it's growth is amazing. Several other permaculture people have agreed with how pleased they are with this cultivar as well. It is still to early for fruit (maybe next year now that it is training out) so no report yet on the most important attribute. Maybe the fruit will be nonexistent or fall off, raisin on the vine, or maybe it will suck but I am really hopeful. All blue grape cultivars here don't color up properly so I am hopeful on this variety for coloration too, but will settle for a good tasting crop. The fall leaves are incredible colors too.
Thompson and Flame are the most reliable around here too.
http://www.lecooke.com/Images/Grapes/Blueberry_Grape%28RGB%29.pdf
I sprayed zinc and boron liquid after that I see the curling in young leaves what should I do for better ment of my grape plant
Why did you spray with zinc and boron? Did you have some reason or some test results telling you the plant needed it? What did you use? Boron can be very toxic to plants even though it is a minor element needed by plants it is needed in extremely small amounts and it can be toxic at very low amounts as well.
Generally we used this type of growth promoter from local market can u please recommend any remedies in this condition
Can you tell me more about what you are using? Maybe you can send a picture of it to [email protected] and then I will understand it.
No sir this type of liquid we used generally for growth of a plant from local market,can u please recommend any remedies for the condition, thanks a lot
I am sending u photo
With your permission I will post that and my response to it on the blog here on a separate post but I will reference this post when I do.
Sir I gave npk to these plant but still a single new leaf come from these plant ,what could I do right now
The most important nutrient needed throughout the year is nitrogen. This should be applied to plants when you see leaf color change from dark green to light or medium green. You can also use the amount of new growth to gauge if you should apply. If growth is strong, dont apply nitrogen. An exaample of a high nitrogen fertilizer is 21-0-0. This might be applied every 6 to 8 weeks if the plant needs it. Look at the plant and judge if you need to apply it or not. Phosphorus is not needed as often. If you apply phosphorus too often it can cause some nutrient problems. So apply it only once during the year. This is at the beginning of new growth. The plant does not need more than this. An example of a high phosphorus fertilizer is MAP or DAP such as 18-46-0 or something similar. Or you can use only phosphorus as 0-45-0. But be careful and dont apply phosphorus often. Potassium will not cause problems like phosphorus. Most people do not apply enough potassium. But it is harder to find. Whenever you apply fertilizer, try to apply a fertilizer that also contains potassium. Sometimes I will use wood ash for potassium if I cannot find a supply of it. But not too much. Maybe only once a year. A good all purpose fertilizer for grapes is something like 10-5-10 or 20-10-20. High nitrogen, lower phosphorus and high potassium. Compost or manure also can be a good source of nutrients. Apply this only once a year before new growth. It releases nutrients to the plants slowly. Apply it one half meter…1 1/2 feet,… from the plants. Not too close.
It's my pleasure
I am sending you the picture of plant and photo of that growth hormone that I used before 15 days , curling percist till now .
Sir I gave npk to these plant but still a single new leaf come from these plant ,what could I do right now
I transplant about 15 cuts from my very healthy 15 years old grape wine at the end of summer and planted them in 4 pots. I now have about 9 new wines. They are inside my walking basement and were doing great without sun. since I moved them close to windows and getting 4 hours of nice sun, my new leafs start cupping. I noticed a bunch of little white color thing on the stems that I think is a kind of aphids and cleaned the stems and spray the whole plants with soapy water. still my new leafs are getting out of shape and cupping.The older leafs that were"t in the sun are healthy. Does the sunshine create extra heat and caused cupping? may be it's the same problem that other people had. Please advise. Thanks
At 115°F I've never had that problem of leaf cupping. I have seen it on citrus and some other plants but not grapes.
yes, yes, yes on the last. Sudden hot, dry winds are common in the high desert.