Nematodes

I believe I have mentioned our struggles with flea beetles before.

And I know that our customers have seen the damage they can do to our crops and understand our need to fight them.

This is what flea beetles do.

Unfortunately, it seems that everything we try is only partially effective. But today, we tried something new.

Nematodes. Specifically, 50 million Steinernema feltiae, soil dwelling parasitic nematodes that attack only insects. Mostly, they only go after the pests - like flea beetles, thrips, and fungus gnats - and leave the beneficial insects alone.

Click here if you want to see where we bought them.

This is what 50 million nematodes look like.

When you get them in the mail, you can't actually see them. All you see is a small package of "inert powder".

So, of course, we had to check and make sure they were really there.

They were.

Then we mixed some of them with water, did a test squirt through our sprayer, and checked under the microscope again to make sure they were still there.

They certainly were.

Finally, I went to the greenhouse and sprayed all the starts that flea beetles find especially tasty, such as cabbage, broccoli, and cauliflower. Tomorrow I plan to spread some in the field on the flea beetle hosts that we have already planted.

You can't see them, but I assure you they're now here too.

Hopefully, they will keep our flea beetle population under control this year. Cross your fingers with us!

Week 10: Late Summer Life on the Farm

The hoophouse and brassicas in the late afternoon sun.

Ah...the last few weeks of August on a vegetable farm. The much anticipated crops - cucumbers, squash, tomatoes - are rolling in and the fall crops are sizing up and ripening without much effort on the farmers' part.

Onions currently curing in the hoophouse. Our work is nearly done here.

Um, right? Because that is what I planned for when I signed up for this farming gig....

Almost. 

We do have a lot of wonderful vegetables to harvest right now, so the week 10 share will include many lovely late summer items: Summer Squash/Zucchini, Potatoes, Cucumbers, Carrots, Tomatoes plus Eggplant/Pepper/Tomatillo OR Ground Cherries, Head Lettuce, Basil, and Kohlrabi.

But we still have a few challenges to contend with.

The cucumbers and squash are definitely rolling in, but the cool nights are slowing down the field tomatoes a lot. We still have hoophouse tomatoes for the shares, and I remain optimistic that we will see a lot of ripe tomatoes from the field this year, but only time will tell. The eggplants are certainly happy! 

And the fall crops are looking great too. We have, among other things, onions curing (see photo above), rutabaga getting bigger and more delicious every day, and lots of lovely winter squash and gourds sizing up on the vines.

Our biggest challenge this year remains pests. The amazing caterpillar pressure we started the season with fueled rodent pressure the likes of which we have never seen. I think mice have gotten as many ripe tomatoes out of the field as we have. 

Then there are the insects. Teeny, tiny, aphids and flea beetles, again at population levels we have never seen before. As I mentioned last week they are going after the greens in the field and, we just discovered yesterday, in our fall starts too.

Redbor kale fall starts look good, only a couple aphids to be seen.

But the Beedy's Camden kale starts are under massive attack.

We're going with the tried and true methods of squishing and dish soap as our first lines of defense (you can see a few bubbles if you look closely in this photo, I'd just sprayed), probably with some diatomaceous earth as a follow up if need be. Kale lovers cross your fingers.

In the meantime of course, you have all the vegetables in your share to enjoy. You are getting kohlrabi again this week, and I know that many of you take them home without much of an idea of what to do with them, so, though last week's recipe was a kohlrabi dish, I am featuring kohlrabi again in this week's recipe.

Kohlrabi are really simple to prepare in many different ways. They taste like mild broccoli stem and are wonderful cooked (as in the stew below) or raw (as in last week's slaw recipe).

Summer's end Kohlrabi Stew

This recipe uses several of the items in your share, but it makes a lot of food. This is easily two large meals worth of stew for us, and we are big eaters. Be sure to serve it with crusty bread or biscuits for sopping up the liquid.

• 1 Tablespoon Olive Oil
• 2 - 3 garlic cloves, minced
• 1 jalapeno (or none or more to taste), chopped. If you have any chipotle around you could use one or two of those instead.
• 1 large onion, roughly chopped
• 1 pound stew beef, cubed (I actually used venison)
• 1 teaspoon salt
• 1/2 teaspoon freshly ground pepper
• 1 large kohlrabi, peeled and chopped into one inch cubes
• 1 pound tomatoes (about what is in the share), roughly chopped into 1 inch pieces
• 2 or 3 medium summer squash or zucchini, chopped into one inch cubes

In a large pot, heat the olive oil over medium heat. Add the garlic, jalapeno, and onion. Stir until they are coated in oil.

Add the beef. Sprinkle in the salt and pepper. Stir to combine. Continue to stir frequently until the meat is brown on all sides, 5 to 10 minutes.

Stir in the kohlrabi. Add water to nearly cover the meat and vegetables. The squash and tomatoes will add a lot of liquid when you add them later, so be stingy with the water now.

Increase the heat to bring the water to a boil, then decrease the heat to simmer. Simmer uncovered for approximately 30 minutes.

Stir in the tomatoes and squash and simmer, uncovered, for an additional 15 minutes.

Colorful stew is the best kind of stew.

Bt to the rescue!

We've added a new pest control measure to our repertoire.

Here is why:

These guys like to eat tomatoes.

And scallions.

And all kinds of leaves, like this eggplant:

They like to eat the flowers too.

They also like pepper plants, chard, lettuce, and beet greens. We've only found a couple in the mustard greens. 

It's pretty unusual for a pest, particularly a caterpillar, to attack so many different plant families with such voracity. Especially scallions. Who ever heard of a caterpillar eating a green onion?

We first noticed them in the greenhouse, around the time we started setting plants out for the season. We didn't think much of them because 1. we've never had any kind of bad caterpillar issues before this year 2. we've seen these before but their population has never reached a problem level 3. we were kind of busy. 

I thought we'd see a little damage, then they would disperse when the weather warmed and they had access to other vegetation outside. But suddenly they are all over the place. They're in the field, in the hoophouse, and still on the few starts remaining in the greenhouse.

Apparently we have a caterpillar problem.

So far, we can easily bounce back from the damage. But if the population increases there will be some significant losses.

So we started a bit of research. It turns out our caterpillars are a Helicoverpa sp. As you might a imagine, they have about a zillion common names - one for every crop they attack. Some of the more popular are corn earworm, tomato fruit worm, and cotton bollworm.

They are very common agricultural pests, but they don't over winter this far north, which is why we have never seen them in large numbers before. Apparently the moths can fly quite a distance in the spring, spreading north. Our best guess is that this spring was warm enough that they arrived in time to squeeze in an extra early generation of northern caterpillars, resulting in the population boom we are currently witnessing.

We've decided to combat them with an equally common biological control method. Bacillus thuringiensis, usually called Bt. Basically, Bt is a naturally occurring bacterium that, when ingested by caterpillars (and only caterpillars) creates a lethal toxin. If you would like to learn a little more about it, please click here. Normally it lives in the soil. We've simply bought some in a concentrated liquid form. We're spraying the bacteria on our plants so the offending caterpillars are sure to ingest some. This control method is allowed under organic certification.

For some of you, Bt may sound familiar because of its association with genetically modified crops. I want to be clear that we are not using anything genetically modified, nor are we using a synthetic pesticide, nor something toxic to anything other than caterpillars. Also, if there is a caterpillar nearby that isn't eating our sprayed crops it will not be affected by the Bt because caterpillars have to actually eat the bacteria before they will produce the toxin.

As for the GM connection. You may have heard of Bt corn. Bt corn has been modified so that all parts of the plant produce the toxic proteins that Bt bacterium normally produce when ingested by a caterpillar. Farmers grow this corn to kill European corn borers, another caterpillar pest of corn.

As a result, Helicoverpa caterpillars in general have been exposed to a lot of Bt toxins, in the form of corn plants, and some have developed a resistance to Bt.

Let's hope the caterpillars currently munching our tomatoes have not.    

Attack of the Flea Beetles

Flea Beetle on Rainbow Kale

Tiny hopping beetles in shades of metallic green or decorated with orange flame stripes, they would be cute. Would be, were it not for their evil streak.

I know that they are just doing what comes naturally to them (See the holes in that kale leaf. That is the nature of the flea beetle.) but I still choose to think ill of them.

As pesticide free farmers we are faced with an annual dilemma when it comes to the flea beetles. Flea beetles eat small holes in brassica plants, also known as crucifers or members of the cabbage family.

Because brassicas tend to do well in cool, short season climates like the Upper Peninsula, we grow about 15 different crops that flea beetles like to dine on.  As long as the plant being fed on is established the flea beetles don't really hurt it, they just cause cosmetic damage.

Like this:

Or this:

Seedlings are a different story. Hungry flea beetles can munch a radish seedling into oblivion if given the opportunity. 

So here is our dilemma. What do we do about this insatiable insect? 

We have a few tricks up our sleeves. Garlic oil sort of kind of helps a little. Row cover (see the photo below) helps even more by literally hiding the tasty brassicas from the beetles.  

Kale, Broccoli, Brussels Sprouts and Cauliflower in the foreground.
Two rows of mustard and radish seedlings hiding under row cover in the center.
Peas and Favas in the back.

So, we use row covers when we direct seed brassicas, to protect the seedlings. Sometimes we apply garlic oil to the row covers if the beetles find their way under. I'm not convinced that the garlic oil does anything but make us feel better though.

Our seedlings almost always survive with this treatment, but not unscathed. Our mustard and radish greens are always a bit holey.

And what about the kale, cauliflower, broccoli, and brussels? They are just left in the open to fend for themselves against the flea beetles.

We start those crops in the greenhouse, then transplant them into the field. By the time we plant them they are too big to hide under row cover, and they would have to come out sooner or later even if we could cover them at first.

There is a chemical option for treating the flea beetles. It's even allowed under many organic certification programs. Pyrethrin. It comes from flowers (Chrysanthemum cinerariaefolium) that look like oxeye daisies. It has been used for 100 years and is generally considered the safest insecticide to use on vegetables. Organic growers use it. It's probably okay, right?


Well...it is a neurotoxin to all insects, not just flea beetles. It is also toxic to fish. It can cause symptoms such as drooling, seizures, and death in humans (granted, only if consumed in large quantities - in small quantities it is completely non-toxic to mammals). 


Every year when the flea beetles attack we say to ourselves "We could use pyrethrin. It would work." And we decide not to.


We don't want to spray poisons on our food. We just don't. So the co-ops don't pay us as much for our arugula, our farmers market customers baulk at the holes in our kale, and we worry that the CSA members won't understand. That's the price we pay for our decision. We think it is the right one.