Hundreds of tiny insects inside row cover. Ack!

[ScottinOregon]

Hi there!

I live in the pacific Northwest (Portland, OR area). I'm new to gardening, and am trying to do some organic vegetable gardening. Really enjoying it so far, but I'm learning the hard way about some pests.

I recently had a leafminer problem show up and it's been attacking my swiss chard. I wasn't using any row covering, but learned that I certainly should. So I've been taking the eggs off by hand and installed some half ounce row cover fabric (rebar and 10' schedule 40 pvc pipe for support), hoping I'd be able to keep the population down by just seeking the eggs out myself for a few days and preventing new adults from coming in.

Anyway, I installed the row cover last evening, and this morning woke up to find hundreds (maybe thousands?...ugh) of tiny flying insects crawling around on the inside of the row cover. They're small enough that they can just move right through the fabric (I watched a few go in and out). As far as I can tell, they're not interested in the chard or the kale that is under the covering; they're just crawling around around the cover, mostly on the inside, along the pvc ribs.

I can't seem to tell if this is an entire population that was already living in the garden and is now confused about being closed in or if they're somehow being attracted to the inside all of a sudden. I'd guess the former rather than the latter, but I don't know.

I'd sure appreciate any advice. I have no idea what to do here, and my Google Ninja skills have failed me in looking for a solution.

Thanks in advance,
Scott

 

[ScottinOregon]

It occurred to me that some pictures might help. Here's what I'm looking at.

 

[Chuck]

It occurred to me that some pictures might help. Here's what I'm looking at.



View attachment 8462 View attachment 8463

I would sure like to see a close up of those little bugs. Also, how far apart are your chard plants?

 

[ScottinOregon]

Thank you for the reply, Chuck.

The chard plants are about 9" apart.

Here's a closer view of the buggers:

 

[Chuck]

Thank you for the reply, Chuck.

The chard plants are about 9" apart.

Here's a closer view of the buggers:
View attachment 8464

I think, but am not sure, that the insects you are encountering are the larval stage of flea beetles. Spinosad, an organic pesticide will easily take care of them, or for that matter, just about any insect that will harm your garden including ants.
IMO your chard plants are a little too close together. Chard is my favorite leafy vegetable and I grow a lot of it. It will grow to well over a foot tall and as wide. My suggestion is that when the leaves of the plants overlap each other harvest every other plant. When chard is crowded there is a greatly diminished air flow and you will more than likely encounter detrimental fungus. It will also stunt the growth of the surrounding plants. Another suggestion is, if you maintain the covering, is to put a box fan at one end and thereby greatly increase air circulation. Chard, for some reason in a greenhouse type atmosphere, seems to attract white fly and movement of air greatly diminishes their numbers. As for leaf miners, they will probably disappear on their own but to make sure spray with Neem Oil, another safe organic product, and it will smother any eggs and also act as a deterrent to any fungus diseases. It will also kill the insects that have invaded your garden, but spinosad is, IMO a better product for biting and sucking insects. Spinosad will not do anything about any eggs

 

[ScottinOregon]

Well, that might end up being a pretty big bummer about the chard spacing! The 9" spacing now is after moving from a direct sow. They didn't like being moved much and it looked like all of the transplants were going to die, but they sprung back to life. I'll try to be conscious of preventing an overlap. Harvesting every other plant makes sense; thanks for that idea.

I've been reluctant to try any pesticides. I think I read somewhere that since pesticides kill the good bugs too, it does more harm than good. Is there any sense to that?

Over the course of the day, I'm seeing far fewer of these little things crawling around the inside of the cover. Either they found their way out or went somewhere else. I don't see any sign of them on the chard or the kale. Weird.

 

[Chuck]

Well, that might end up being a pretty big bummer about the chard spacing! The 9" spacing now is after moving from a direct sow. They didn't like being moved much and it looked like all of the transplants were going to die, but they sprung back to life. I'll try to be conscious of preventing an overlap. Harvesting every other plant makes sense; thanks for that idea.

I've been reluctant to try any pesticides. I think I read somewhere that since pesticides kill the good bugs too, it does more harm than good. Is there any sense to that?

Over the course of the day, I'm seeing far fewer of these little things crawling around the inside of the cover. Either they found their way out or went somewhere else. I don't see any sign of them on the chard or the kale. Weird.

I too don't like to use pesticides unless necessary either, but if it comes down to losing or limiting your crop in order to save a few beneficials then so be it. Those insects sound like a swarm of some sort, maybe some kind of ant and if they are heading elsewhere don't worry about it. Keep a close watch though. Those little flea beetles can do quite a bit of damage

 

[ScottinOregon]

I really appreciate the help. I'll watch for another day and if they're still around, it'll turn into (organic) chemical warfare.

 

[Beth_B]

Yikes, almost look like fruit flies but probably what Chuck said.

I'm another organic, but when schmidt gets real I'll use pesticides, gardener. My rainbow chard has been doing fantastic this year. May not be a viable option for you in the PNW because moisture renders it ineffective, but diatomaceous earth is another strategy for any hard-shelled insect. It works mechanically, not chemically.
http://www.richsoil.com/diatomaceous-earth.jsp