Hank,

If the flies are small black to gray flies with yellow markings, they are probably spinach leaf miner flies.The female flies will lay their white eggs on the underside of the leaves. When the maggots hatch in 2 to 4 days, they will eat their way through the part of the leaf that lies between the upper leaf suface and lower leaf surface, leaving winding, white tunnels. In about three weeks the maggots will pupate and mature into another round of flies. The cycle will repeat itself several times.

It could be whiteflies if they have a whitish appearance. Whiteflies are very small flying insects, but they are not actually flies. If you could view one under a magnifying glass it would look more like a tiny moth than a fly. Whiteflies feed on your plants and excrete a sticky honeydew in which a black fungus or mold will grow.

Finally, it could be flea beetles. They are tiny and more or less black and eat little holes in the leaves. Some of them have red heads. There is one specifically called the spinach flea beetle. When I have flea beetles they tend to attack veggie transplants that have been set out in the garden recently. When you wave your hands over the plants, the flea beetles jump up into the air.

For any of these you could try an insecticidal soap or a general-purpose insecticide.

Dawn

I was about to ask where they came from when I realized that this is the reason for using sterile potting soil to start seeds with, isn't it? So I can blame the place that started these plants, right? Except I got them for free and the ones planted in other gardens are doing OK.

I do have a black thumb after all.

Hank,

They could have come from anywhere, you know. They have been hanging around, lurking, just waiting for someone to plant something they really, really like so they could gobble it up.

Insects are just a part of the natural world. Sometimes it does amaze me that they can find gardens that contain the very plants they most want to eat.

Take asparagus beetles for example. There are not an overwhelming number of gardeners in Oklahoma who grow asparagus. However, just plant some asparagus in your vegetable garden and somehow the asparagus beetles will find it. How do they do that?

I have found that garden pests are the worst in new gardens. I guess a new garden is like a buffet to them.

I think the insects are worse in general if you don't have a lot of the good bugs like ladybugs, green lacewings, trichogramma wasps, beneficial parasitic nematodes, predator mites, spined soldier bugs and praying mantids. The good bugs help keep the bad bugs under control. It took me a long time to learn this.

When I was a kid, my dad always raised tomatoes. Every year, about late June or early July, the red spider mites would show up. They showed up not just on his plants but on the tomato plants of all his gardening friends in our neighborhood. Once the red spider mites showed up, you knew that your plants' days were numbered, no matter what you did. The gardeners would whip out the Kelthane and spray the plants and it seemed that, instead of helping control the spider mites, it made their population spiral wildly out of control. No matter what you did, the mites got worse and worse and worse.

As a young adult with a new (to us) home and garden, I planted tomato plants. About the 3rd or 4th week of June, the spider mites showed up. We sprayed with Kelthane and got the same results my dad always got. More spider mites.
It really made me crazy.

The second year we were there, 1985, here came the spider mites in late June. I was already beginning to move towards gardening organically, so I decided I would not spray Kelthane on the plants. Guess what? The spider mites never went away, but they didn't get worse and they didn't kill my plants. I began to understand that spraying a poison miticide or insecticide did not guarantee a bug-free garden.

Still, it took me many years to really understand it all. As I gardened organically, I came to have more and more good bugs over time and fewer and fewer bad ones. It took me FOREVER to really grasp the concept that the good bugs were keeping the population of the bad bugs under control.

What I finally learned, from reading a lot about organic gardening and THEN from seeing it in my own garden is this: if you spray a miticide to kill spider mites, it will kill ALL the mites, including the predator mites that eat spider mites. The bad bugs always rebound first as the predator bugs won't arrive until there is a good supply of bad bugs to eat. So, by killing off the one insect, the predator mites, that would kill my red spider mites, I had actually made my spider mite population worse.

Nowadays I have a good balance of bugs in the garden and the good ones help keep the population of the bad ones under control. Even though insect and mite damage is unsightly, it usually won't kill the plants.

For what it is worth, this year I have the fewest bad bugs I have EVER had. I can't explain why, but I would say my bug population is only about 10% of what it normally is. It might be the cold weather we had in April killed them off and they have been slow to rebound. It might be that last summer's drought killed off a lot of them. Whatever the reason, I am enjoying it.

Dawn