I discovered an invasion in the lettuce and greens garden, but I did find out how to destroy the invaders, organically with food grade diatomaceous earth. You can see the Flea Beetle invader and the chewed up Rocket Arugula in the picture above.
Diatomaceous earth consistency is powdery, it's fossilized remains of aquatic organisms. When bugs crawl around in it, it gets in their joints - like little shards of glass it rips up their joints and immobilizes/kills them. It does not harm humans or animals. This is food grade diatomaceous earth, there are many farming, animal, and human health uses (Source) - it kills all bugs, including ticks, spiders, roaches, bed bugs, silver fish, ants, fleas, slugs, silverfish, beetles, centipedes, etc. (Source).
I removed the bug netting from the garden row box to sprinkle some diatomaceous earth onto the greens being eaten by the flea beetle - these pests found their way into the garden before the netting was added.
So far this flea beetle has been only eating the greens, not the lettuce - I did plant the greens a week before the lettuce, so it's possible it's just the timing, but I haven't found a spec on the lettuce plants. I first noticed the little holes on the mustard greens and tatsoi, I was hoping it was just from growing up through the hay, but the new leaves have them too.
As I took a closer look at the Arugula, I finally caught a glimpse of the pest.
The Rocket Arugula was hit hard too, along with the smaller Dragon and Voyager Arugula rows.
You can see below that the spinach is untouched and looking good - definitely a leafy green, but it was much later to pop out of the ground, so it seems more like timing.
It's mostly lettuce on the the North Side of the garden box.
The Green Aerostar lettuce is doing well, no flea beetle bites...
The Purple Aerostar lettuce has a solid and deep purple, lovely...
The flea beetles did manage to find the Mizuna Greens. Nice looking greens, before they were munched on - also one of the earliest greens to pop up in the garden.
The Romaine's coming along nicely, I'll have to water this garden soon, there's no rain in the forecast until Sunday night...
The Salad Bowl Lettuce is filling in, no bites on these...
The Royal Oakleaf Lettuce is off to a good start too...
The Flea Beetle Fix is In
I grabbed a hand full of the grainy and powdery diatomaceous earth and started shaking it generously onto the Flea Beetle bitten greens. Most of them should be dead or disabled in a few hours - after 24 hours I'll rinse the white powdery diatomaceous earth off the leaves with a generous watering.
I re-covered the hoop row with the bug netting.
I inspected the plants this morning, no sign of alive or dead beetles, good enough. I'll have to keep a close eye on the new leaves to watch for bite marks, and for any other signs of pests.