Up to now the garden has been free of pests. Last weekend I noticed the white cabbage moths fluttering around the garden, so I knew I had to get protection in place soon for the brassicas. So I spent Sunday putting up the hoops and row cover to protect the row of broccoli and kale in my in-ground plot. On Monday I took a look at my turnips and radishes in the raised beds and was amazed at the flea beetle damage done in just a few days. Just a few days ago there was not a hole to be seen, now the plants are crawling with the tiny black beetles.
The Broccoli raab and Soloist Napa cabbages were doing really well and are now just pin cushions. It doesn’t pay to be a pioneer, you just wind up with arrows in your back. There are no brassicas elsewhere in the garden and no wild mustard anywhere near. When you get a hatch of hungry crucifer flea beetles and your garden has the only meal around, expect to be attacked.
Likewise, the radishes and turnips are damaged, while the kohlrabi are untouched The trouble I have is they are small plants that get put here and there in the garden and it is difficult to come up with a system to protect them. These were sprayed heavily with Spinosad on Monday to hopefully knock down the population. Spinosad is effective against flea beetles but is not yet licensed for them. I will alternate the Spinosad with a pyrethrin spray. Both are approved for organic gardens.
For the in-ground plot, I am organizing it by row. The row in the back is the large-rooted brassicas, specifically broccoli, kale and Brussels sprouts. I used black plastic mulch to minimize watering and inhibit weeds. Since these plants do not have to flower (in fact, we do not want them to flower), they can remain covered. The hoops you see are 10-foot (3 m) sections of inexpensive 1/2-inch (1.3 cm) plastic electrical conduit, pressed into the soil and bent over. The material is PVC, which is not ideal, but at least it is marked to be UV-resistant. You could use PEX water tubing, but it is not UV-resistant and rapidly breaks down when exposed to sunlight.
The key to this system is the availability of 10-foot wide (3 m.) fabric. I used Agribon 19 which I sourced from Johnnny’s Seed. I bought the 250 foot roll so it should last me a while. The trick was to get the fabric over the hoops. Of course, as soon as I was ready to raise it over the hoops, a breeze started blowing. I had to have another gardener help me and I had to use large binder clips to hold it in place. So far it has held up to the usual windy conditions we get in the spring and the brassicas underneath are bug free (although they got sprayed with the Spinosad just in case). It’s necessary to seal the edges because the flea beetles are fully capable of getting underneath. Hopefully this will keep the plants beetle and caterpillar free this summer.
I also saw my first cabbage butterflies this past weekend and was busy putting up more netting yesterday. I plant all of my brassicas together just so that I have an easier time when it comes to covering them up. Those flea beetles really did a number on your plants - do they come in stages or would they be here to stay for the entire season?
ReplyDeleteNo, the flea beetles are here to stay. So are the cabbage moths. They were still around last October and that's when the caterpillars did the most damage.
DeleteThe row covers I use aren't good enough to keep flee beetles out. But I so hate Agribon 19. It is so fragile and I can't see through it well. I use two kinds. One is pretty sturdy but horribly expensive, white, and you can't see through it any better than Agribon. The other is just cheap fabric netting, which is prettier, cheap, but about as fragile as Agribon. Though the wind goes through it so there isn't as much stress on the fabric. Luckily for me flea beetles aren't too much of a problem here as both have holes big enough for one of those to get through. I have such a love hate relationship with my row covers.
ReplyDeleteAgribon 15 would be better to use because it lets more sun through but it isn't available in the size I want. If I'm careful I get two-three seasons out of it.
DeleteYikes, those flea beetles are a menace in your garden. I see them here, but not in the numbers that you get.
ReplyDeleteI know the "when your garden is the only meal" feeling ... it seems like every pest pops by my yard first to see what's for dinner! I have not noticed cabbage moths here yet, but if Margaret has seen them, they won't be far behind for me.
ReplyDeleteFlea beetles are terrible. They are really going after your seedlings. I use diatomaceous earth in early spring for eggplants but rain does wash it away.
ReplyDeleteI gave up eggplants for a few years because of them I grow a few Ping Tung eggplants now which seem to be a little more resistant.
DeleteHere in the UK we can get a product called "Enviromesh", which is a type of very fine-mesh net. It comes in various thicknesses / mesh-sizes. It is pretty strong, yet still lets through about 80 - 85% of the light. I used it last year to protect my carrots from Carrot Root Fly and it worked a treat.
ReplyDeleteI ended up having to sew mesh bags for my eggplants. I have a drawstring at the bottom and a zip up the side. It doesn't keep ALL the flea beetles off, but it reduces them to a survivable number. I also fight them with duct tape. I wrap it around my hand, go out in cool temps when the bugs are sluggish, and stick the tape to each leaf removing the bugs. Also works for other small beetles.
ReplyDeleteWow, mesh bags with zippers. That's too ambitious for me. I do pick the beetles off before I spray, but not with tape. I just roll them between my finger tips to crush them.
DeleteThat is a great setup for the row covers. I use shorter hoops for mine since the veggies aren't in the ground all season, only spring or fall. I am thankful we don't have a bad flea beetles problem here. I can deter them with neem oil, and they seem to favor eggplant but not the brassicas.
ReplyDeleteThat's because there are different species of flea beetles that feed on different crops: http://davessfggarden.blogspot.com/2013/06/flea-beetle-management.html
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