Leaves Turning White and Papery - Peppers and Tomatoes - Answered

Today after work, I ambled out to the garden for my daily check-in.  To my dismay, my sweet peppers and tomatoes are exhibiting a problem that's totally new to me.  Portions of the leaves are turning white and going all flimsy.  When viewed from underneath, it's clear that something has sucked out all the green part of the plant and left just a paper-thin white remnant in the shape of the leave but with no internal supports.  The white part is like a soft gauze.

I don't know how else to describe it.  Here are some pictures:

On the picture above, you can see that the tips of my pepper plant are complete turned to gauze and the affected area extends around the entire perimeter of the leave.  On the left hand side, that portion that is hanging down along the center of the leave is a part that tore off when I tried to handle it.

Here are a couple of other plants.  In the picture immediately below, you can see the papering on the right hand leaf, but on the left hand side, that's not a flash glare on the leave but rather whiteness from the same problem.  

 

All of the above pictures are of my pepper plants, but there is at least one tomato suffering from the same ailment.  The tomatoes and peppers are planted adjacent to each other. In the below picture, again, while it looks like sunlight is reflecting off the right-hand leaf, it's not.  I took this at dusk.  That is whiteness of the leave all around the edges. 

This is freaking me out.  If this much damage can happen in a 24 hour period, I fear what I'll come home to tomorrow.  Decimation of my peppers?

All of these plants have been hardened off and have been outside weathering heat and cold for some time now.  So it's not sunburn. 

I looked diligently for pests and could find none on the leaves.  Perhaps it's a disease??

Amy - help!


ANSWER

I haven't ever encountered this before, but I'm afraid it might be a kind of virus. There are several mosaic viruses that are vectored by aphids. You can't kill the aphids before they infect your plant, and both peppers and tomatoes can "catch" them. There is the cucumber mosaic virus, the tobacco mosaic virus, the alfalfa mosaic virus and a few others. If I had to make a guess, it would be cucumber mosaic virus, as it affects the most plants. Unfortunately, there isn't any treatment. There is only eradication and prevention.

Once an aphid has contracted the virus, it can only infect a plant within a few hours. But flying aphids actually move around quite a bit, so the viruses can spread very quickly. They like to probe a lot of different plants until they find the right one. It's nearly impossible to control for the aphid population if the virus is spreading around your area.

The tomato plants look more like the typical mosaic virus, in that there are separate spots around the leaves that turn white. But the symptoms are pretty varied.

I've gotten to this a little late, so can you give an update? Sometimes plants can overcome the virus, but the general consensus involves sacrificing the plants. Otherwise it can spread. Unfortunately, the other recommended action is to get rid of all weeds in the area. I understand how difficult that can be, if you don't control an entire field. Can you check for symptoms in some of the weeds in the area?

Now for my disclaimer: it's entirely possible that there is some insect that causes these symptoms and I just haven't encountered it yet. Before sacrificing all of the plants, it would be worth it to pull one and check it's roots, under the leaves and all over it. It could possibly be a powdery mildew, but you should be able to rub that off.

I wish I had a better answer, but this type of damage makes me nervous too. Especially the damage I see on the tomato plant.

UPDATE

I think you might be right.  I did some further internet reading on mosaic viruses.

- http://www.extension.umn.edu/distribution/horticulture/dg1168.html
- http://www.extento.hawaii.edu/kbase/crop/type/cucvir.htm
- http://www.ipm.ucdavis.edu/PMG/r783102811.html

This really really really sucks.  I do remember finding some clusters of aphids on my peppers during the hardening off process, back when I had two flats into which I crammed all of the peppers and tomatoes together.  The aphids may have come from my yard or they may have come from the ONE tomato plant that I bought (at the Tilth sale) and set in with all my home-grown seedlings.

But I fear I might be the vector.  I tend to touch my plants when examining for insects, turning over the leaves and such.  I have certainly not been washing my hands with hot soapy water in between touching each separate plant, or disinfecting my garden tools by boiling them for 5 minutes, as recommended by the UMN website. 

In the time since I last posted, things haven't changed much, although the problem does seem to be getting worse with respect to the peppers.  Here are some additional photos:

All of the above pictures are on my peppers, which are planted in front of the tomatoes. 

This picture below is one of my tomatoes that I planted separately in a pot against the house.  It has a lot of white spotting, and something has also been eating the leaves.  The fact that this tomato exhibits the white spotting tells me that the spread of virus occurred back when I had all of the seedlings in flats together with the peppers, rather than spreading in the garden bed (because this one is in a different part of my yard far away from the garden bed).  

My plan:

1.  Pull out the peppers and the worst-infected tomatoes in order to try to save the tomatoes that so far look uninfected.  This makes me very sad, by the way.

2.  STOP touching the plants with my hands and will boil my hand tools today and wash with soapy water.

3.  Throw away my pink gardening gloves that I used when doing most of the planting and tending of these plants.  I have some new ones that I haven't used yet this season, and I'll switch to those for handling soil and any other plants. 

4.  Cross my fingers and toes.

I'll post updates along the way.

Broccoli Leaves and Aphid Poop

Amy,

Creatures are feasting on the leaves of my romanesco broccoli. The good news is: they left the gorgeous purple broccoli head untouched, and I'm probably going to eat it soon anyway, so no worries. This is the last of my romanescoes this year. I started with six plants, and the other five all matured much earlier this spring. They are delicious - very delicate flavor when steamed and served with butter and salt and pepper. For some reason, this one lonely broccoli took much longer to mature than the other 5. None of my broccoli plants showed any pest damage until now.

I peeked under the leaves and found some aphids (see below). But the aphid population isn't all that large. The picture shows one of the largest clusters that I found. Are the aphids causing the main damage, or is it something else? I would like to know for future reference and also to assess whether the problem might spread to my other veggies nearby, which include swiss chard, leeks, carrots, tomatoes, green beens, and squashes.

Rachel,

So, the good news is that the aphids aren't really a problem. I mean, get them off of there before the population explodes. If you have a few warm days, that little colony could overtake the garden. Seriously. Females can reproduce asexually. Each adult female can produce up to 80 offspring in one week. Each of those 80 offspring then produce 80 of their own, who produce 80 more. That brings us from 1 female up to 512,000 aphids in less than three weeks. Anyway, wipe them off. I assume you already have, but it bears repeating. Do this even though you're about to harvest the broccoli, cause they'll just create some winged forms, pop out a few males, and fly over to your tomatoes to start all over again.

Aphids don't take bites. They have piercing sucking mouthparts. It's like a straw. They insert this straw into the leaf and look for a vein full of phloem. This is the sugar/sap and basic life-blood of the plant. They drink a lot of this. Actually, they drink enough to poop out some stuff that is basically sugar. We call this honeydew. There's a lot of evidence suggesting that the manna the Israelites ate was Honeydew from a particular kind of insect. It's pretty sweet, and not at all poopy tasting. (and I probably shouldn't admit that I know that, but, whatever). Ants will eat it. Ants will actually farm honeydew producing insects, protecting them from natural enemies. So, while ants are not pests, they're a pretty good indication of a problem if you find them all over a plant. Anyway, you can see how the leaf has turned yellowish underneath the aphids. That's typical aphid damage.

About the bites. Are you sure that's not slug damage? I'm less familiar with slug damage. I always look for slimy trails, because I can never remember the size of their bites. Those don't look like smooth margins. You have a lot more experience with slugs than me, so I'll defer. I'm curious about your slug program, though. Have you ever used beer traps? Copper barriers? I've heard inverted melons work really well too.

If it isn't a slug, then it's probably some type of caterpillar. These things are voracious. Since you'll be harvesting soon, let's focus on preventative measures. Look for caterpillars in the early evening or late morning. A little Bt wouldn't hurt, just as a preventative for your nearby plants. I'd suggest that you at least remove all of the leaves right after harvesting. It might be a good idea to remove the plant and turn the soil.