Every Spring around the first of May, my garden gets an infestation of flea beetles which chew those tiny pin-holes in my arugula, mesclun mix, radishes and other such greens. I've tried row cover, but it heats up the bed so that my crops bolt too early. Last year I resorted to using a rotenone/pyrethrum spray, but I really don't want to do that again as it will kill beneficials as well--though it is organically acceptable. Has anyone tried using a hand-held vacumn cleaner on the little beasties? Ideas anyone??
Here is the pamphlet on flea beetles from our extension service: http://www.ext.colostate.edu/pubs/insect/05592.html
Dr. Cranshaw, who wrote it, told my Master Gardener class that flea beetles are the toughest insect for the organic farmers he works with. He hasn't found a method he is completely happy with, either.
You may already know this - but row covers come in different weights that allow different ratios of light transmission or heat insulation. You would want one with the least insulation value, and here in Colorado I would probably use a shade cloth suspended over that.
Last year I had them on flowers. I vacuumed them, it worked okay (vacuum works better on squash bugs). Plan on cleaning your vacuum and/or changing the bag and filter afterwards - beetles will make the exhaust smell bad.
This year I'm interplanting catnip with the zauschneria (mild infestation) to see if I can get them to move on to a trap crop (nasturtiums, radishes) that they like better.
Many thanks for your input here, pollengarden! Sounds to me that a multi-pronged approach is my best bet--using every method possible. I can start with the row cover, then use organic insecticides, and keep the vacumn handy. And...hope for the best!