There could be a few "dead" whiteflies but more likely what you are seeing are molts of their exoskeletons. They shed their skin as they grow from sucking up all those plant sugars.

The plants are being sapped of energy from the whiteflies. Whiteflies can transmit some disease but it's iffy if that is the case. They are likely just sucking energy from them.

The interior leaves have done the Spock thing in the Star Trek: Wrath of Khan movie -

"the needs of many outweigh the needs of a few"
- that is to say, due to limited energy, the plant is giving up trying to maintain shaded interior leaves for the sake of the other leaves which receive more sun (and thus are better at supplying energy).

Whiteflies are tough critters because they fly off when you try to spray them.

Yellow sticky traps are a slightly effective method to deal with some of them.

I had a problem with them here until it got warmer and dry. Now I dont see them hardly at all.

WHITEFLIES!

Try doing a Vulcan mind-meld on your plants. See what they say about it. Failing that, turn your plants' cloaking devices on to make them invisible. It will drive the whiteflies nuts. They really hate that. It's a dirty trick, I know.

An infestation of whitefly strikes complete horror when I see it (second only to thrips) as they are vectors of disease and severe infestations cause irregular ripening of tomato fruit. I have turned over every leaf of many many plants just to rub out early stages of whitefly.

They are very difficult to control once established. But I am not quite sure if you mean you only have 'dead' ones --there are many beneficials that do help reduce their populations.

If you tap the plants do they flutter out. Turn the leaves over , some stages are stationary but you should see movement of the adult whiteflies.

If you do see live whitefly I think I would go with an insecticidal oil or soap and oil spray as they build up resistance to chemicals very rapidly. Or I might try something like spinosad which I have used on thrips.

Scroll down to the very bottom of the link to see recommendation to the homeowner. I would take great care to spray under the leaves.

Yes the damage you describe could be from whitefly I think but at least you are not describing symptoms of tomato yellow leaf curl virus (TYLC). I have seen a few plants with TYLC symptoms and I reluctantly just put a garbage bag over the whole plant and pulled it out. Your whiteflies may not be carriers of TYLC.

I love experiments and would be interested in your MG vs fish emulsion one. Hope you can get a handle on your whitefly problem.

Here is a link that might be useful: Info. on whitefly

Not whiteflies -- they readily move if you disturb them.

Not whitefly molts, because they don't do that.

More likely, the cast skins of aphids.

Jean, those are good points. Lets hope you are right. An aphid infestation doesn't sound too bad nor would it be difficult to control. They do vectored Cucumber Mosaic virus but he is not seeing those characteristics (ie leaf shoe-stringing) at all.

Bart1, I highly recommend a 10x hand lens (cheap ones are around $10 , good ones around $30. It is interesting to see whitefly stages magnified and you can see close-ups of aphid cast skins and some that are parasitized.

Hope your tomatoes live long and prosper ........

D.

Thanks for all the help everyone.

If it is aphid castings (is that the right term?) should I do anything about them? Or have they had their "bloom" and are now gone for another year?

Or do they have many generations per year and the problem will just keep getting worse if I do nothing?

Thanks again,
Bart

Bart, I think you need to ID this correctly one way or another. You also need to determine if you have an active live population of whatever it is.

Here is a picture of adults and cast skins. (aphids also come in other colors). Some aphids look 'blown up' like a balloon and these are the parasitized ones and you can see the exit hole where the beneficial wasp escaped.

You can take a hose and try to blast them off with plain water. Then repeat later.

Whitefly as mentioned above would flutter up when you shake the plant.

Here is a link that might be useful: {{gwi:1366942}}