Causes of leaf curl?

[spyfferoni]

I have several of my plants that have leaves curling up. Some of the plants only have some of the leaves doing it, while others the whole plant seems effected. I hope I don't have the tomato Curly Top virus. I noticed some black aphids? on the plants and some of the undersides of the leaves are shiny, like something or the plant has oozed something on the leaf. I'm wondering also if the Cucumber Mosaic virus causes curling---I have some plants that look like they might have that---from what I saw on the tomato disease photo gallery. I need to get some new batteries for my camera, and then I'll try to take some pictures tomorrow. If I do have either or those viruses, is their anything that can be done? Also, can weeks of temps in the high 90s and triple digits cause leaves to curl?

Thanks,
Tyffanie

[montanamato]

tyffanie...Probably the heat at this time...It is getting to be late enough to be out of danger from curly top...If it is the virus, the lower branches often get a weird angle and hang down. The leaves get tough and leathery too. The actual top of the plant that is curling will get sort of disfigured looking and skinny...If just heat curl, the leaves and plant look pretty much OK, just upward curling....Look closely on the stems and near where curling is happening...You should see some little thrips if curly top virus is the problem. The thrips are spread to my garden from mustard weed that is widespread in a lot of our pastures...The wind carries the thrips into my garden and the lower end has already gone down to curly top...My upper plants are so huge and thriving I am pretty confident I am in the clear on those...Generally town gardens that aren't next to fields or pastures should be pretty safe.

Jeanne

[carolyn137]

Also, can weeks of temps in the high 90s and triple digits cause leaves to curl?


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For sure.

I think some time spent looking at the Problem Solver thread which is near the top of this Forum might be very useful for you in terms of distinguishing between Curly Top and CMV, for instance, as well as other possibilities.

But to answer your question directly, leaves curl when the plants are too wet, too dry, too cool or too hot. And they also can curl when there's a heavy fruit burden. In addition most modern hybrids have leaves that curl.

If the leaves curl over into a tube like structure then look for aphids.

Other than that I totally ignore curling leaves unless other symptoms appear.

Most viral diseases cause not just curling but actual distortion of the leaves as I know you'll see when you look at some of the links in various posts in that Problem Solver Thread.

[spyfferoni]

Are there black aphids? What I see on the tomatoes are tiny black fly, gnat looking things. We have new sod and have been watering a lot so it will make it through the heat, this seems to bring additional insects/gnats into the yard.
How often should I be watering my tomatoes when the temps are sooo high and we are in a drought? I have most of my garden on a drip system that is supposed to water the plants 1 gallon per hour. The plants bordering the lawn I don't give extra water because they seem to get some water from the sprinklers. If I do have aphids what do I do to control them??? Something is definately eating my pepper plants too. I'll get out and take some photos today.

Thanks so much!!!


Tyffanie

[Suze]

Originally Posted by spyfferoni

Are there black aphids? What I see on the tomatoes are tiny black fly, gnat looking things.

Yes, there are black aphids; they can be a variety of colors. Do a Google Images search on "black aphids" (use the quotes) to see pictures. Maybe they could be gnats though, if that's what you think they look like.

Try to decide first if aphids are your insect, then we'll go from there.

As for your peppers, aphids wouldn't be eating them. From the wording of your post, wasn't sure if that's what you meant or not. I find flea beetles to be a fairly common pepper pest (at least here anyway), but of course it could be something else eating them too. How big are the holes?

How often should I be watering my tomatoes when the temps are sooo high and we are in a drought?

Can't give you specifics about drip rates, because I don't know much about it. But I will say overwatering can be counterproductive. It is tough to give specifics about how much someone should water -- there are just so many variables involved including soil structure (free draining/loose or clay, etc.), plants mulched or not, temperatures, relative humidity, and so on. One thing I am a big believer in is training plants early on for deep infrequent waterings. A way to help accomplish that is to mulch well, and of course, water deeply/infrequently from the get go. This forces plants to send roots down deep, and I find makes for a healthier plant that is better able to withstand stresses in a warm climate later on -- including underwatering, and yes, even the occasional overwatering due to torrential rains.

In the absence of rain, I water every 5-7 days (even with mature plants loaded with fruit). My soil is extremely free draining and in raised beds, but I use a lot of mulch. Most warm climate folks would say they water a little more than that, I suspect.

The one gallon/hour rate you mentioned doesn't make sense to me; do you mean per row/bed? How long do you let it run for?

[spyfferoni]

The one gallon per hour rate is per emmiter. I have them set up right now to receive a 1 gallon every other day. I realize that is probably too frequent, but I set it up that way because I was worried about my plants while I was away for a week. I'm going to lower it to once or twice a week for an hour and a half which is supposed to be 1 1/2 gallons of water. The holes in my pepper leaves range from tiny to about as big around as the sharpened tip of a crayon, maybe a little bigger on some plants. I had a problem with snails in the Spring, so there may be a multitude of insects eating at my plants. I have a light gray weed block material and some grass clippings for mulch. The grass clipping don't always stay put because of the wind. I lost an apple tree from high wind last night. It was 3 years old, pretty small still and had its first good crop of apples. My little boy cried. It totally bent over at the base of the tree and broke. That's the kind of wind we deal with on occasion.

Thanks Suze!

Tyffanie

[montanamato]

Tyffanie...I can't keep mulch down either, due to winds...We have high winds for 6 plus hours a day most days anymore...I find w/o mulch I sometimes overwater too...I usually dig down in my lower tomatoes and if it is dry I water...I am watering daily but we have 102 and 30 mph winds all day long. My containers are drying out much quicker than in past years.
The little black bugs sound like the thrips that bring me curly top...I hope not, but you should be finding out soon.
Whenever I have aphids the ladybugs are quickly on the rise, and have always kept thing under control in a short time. Are you noticing any ladybugs ?
Good luck.

Jeanne