Bear with me as this may be a bit lengthy...

Two years ago, when we moved into our new house (in Texas), our red tipped photinias were 12 - 15 feet tall. I wanted them cut down to shrub height, unaware of their susceptibility to different diseases (we're from Michigan.) Within a week of being pruned, they began to show signs of leaf spot.

This year, I did an extremely aggressive rejuvinative pruning on them. I cut them all down to about four feet tall and stripped them of all branches and leaves. As the new growth began appearing, I sprayed them every two to four weeks with a fungicide/insecticide in the hopes of preventing the leaf spot, or whatever malady was affecting them, from returning to the new growth. So far, so good.

Well, I can't say that the leaf spot has returned, but I have areas where the leaves are dried, curled, and or the edges are brown. I am now noticing these incredibly small (like the size of a pin-head), bright green bugs on the leaves, but they don't seem to be eating the leaves. These bugs are killed by the chemical I sparay on them, but return rather quickly. I'm not even sure they are damaging the bushes in the first place.

I'm trying to maintain my lawn organically now. This weekend, as I was spreading cornmeal on the grass I thought to myself, "What the heck. It has fungicidal properties, why not throw some on the bushes?"

The next day, I was out in the yard again, and happened to look at the bushes, not expecting to see anything. I was quite surprised to see all these little green bugs had turned black and died.

So, is this coincidince? Does cornmeal have insecticidal properties? It almost appears that the cornmeal dehydrated the bugs.

Anyone's thoughts?