The first Aphids are finally starting to show up. I've killed about a half-dozen so far, all before they were able to produce any offspring as far as I can tell. Still for everyone I find I'm sure there are a dozen more I've missed. I've been doing a complete search of every one of my tomato plants each morning. They're still rather weak due to some chilly nights, and I don't think they'd handle an aphid infestation well.
At this point in the year the Aphids should all be the first generation hatching out of eggs that have over-wintered. They're so huge because they're full of offspring that they will give birth to live. From the first generation on its all live aphids until the last generation of the year in the fall that again produces eggs. Taking care to kill these first aphids can have a positive impact on stunting future generations. Still I'm sure they'll become a problem despite my best efforts, just as they were last year.