I've had to ditch two tarragon plants and four pansies due to aphid infestations. One minute things are hunky-dory, maybe some brown edges or other signs...then THEY'RE EVERYWHERE.
I returned from a two-day trip to find an eggplant flower and impressive progress of our first tomato and jalapeno fruits. Doubling back later to admire them again, I noticed some tiny holes on the eggplant leaves; sure enough, with closer inspection on the underside of the leaves, there were aphids. Being an urban gardener without a hose to spray them away, I gave the eggplant and tomato plants a treatment of neem tree seed oil-based insecticide. I've had good results with insecticidal soap in the past on bush basil that was aphid-infested.
Of course, that is a rain-dotted balcony door you see in the photo above, so hopefully the neem did its trick before being mostly washed away.
I'm a little concerned about my urban crop because I've been seeing bugs more often these days, and a little image Googling has identified them as flea, cucumber, squash and insert-vegetable-name-here beetles. Yes, where there are vegetables, there are bugs...I was hoping that the leaf-shredding winds of our balconies and rooftop would at least provide us the benefit of blowing away insects. Who knows? Perhaps we would have much bigger problems if we were ground-level in-ground gardeners; at least our plants are not sitting in puddles of water.
On a positive flying-thing-note, there has been noticeable increased bumblebee presence this year over last.