Out there (Tucson, specifically) the best protection I've seen are those that totally enclose the garden with a breathable/mesh shelter around their planting area...which is neither attractive, nor convenient to install/maintain (especially with the wind). Small fences work in some more urban or less animal-active areas. There's a quite active AZ Gardening forum on GardenWeb...some people there might be able to help you out. http://forums.gardenweb.com/forums/azgard/ Here is a link that might be useful: GW AZ Gardening forum

When insects attack (should make a good TV show) ..... ..... plants mount a number of genetically encoded responses to the wounding, ALL of which require energy allocation. In plant cells, there are genes that control proteins functioning in defense, sending defense signals, altering metabolism, controlling cellular maintenance, and regulating photosynthesis, as well as many genes of unknown function. In short, plant energy reallocation is prioritized in the plant's own defense, & other things, like every day metabolism and photosynthesis are put on the back burner. When wounding occurs (insect attack) there is a "wound response" that occurs both at the site of injury as well as distally (in other plant parts). Plants can even differentiate between the wounds of a pin and those of insects and react in different fashion to the "attack". Without getting more technical, the plant produces various anti-feedants, anti-metabolites, and toxins that make the insects feel pretty unwelcome - as long as the plant is in good vitality, which means growing strongly, or has high energy reserves. In other words, as long as the plant is in good health. Stressed or strained plants cannot quickly or efficiently respond and ward off insect attack. The speed with which the response occurs, and the effectiveness of the defense response are also both energy driven, so it should be no surprise that plants grown indoors under constant stress are highly susceptible to insect marauders. If you want to keep the bugs away - your first line of defense should not be to reach for a systemic poison, but to keep your plants growing with as much vitality as possible, which is a cultural - not a chemical thing. ;o) Al

Ein-Yahav collectively produces about 34,000 tons of peppers, watermelons, melons, tomatoes and other vegetables ****in protected greenhouses, net houses and tunnels*****. Because they need that so the bugs stay around. And they are constantly introducing fresh predators. ====== we have one month during summer when it is not allowed to grow anything in your plot, in order to make a vacuum �" if there are no plants, the insects die off. Then, when you plant in August, you start the season without insects and without any need to spray.â Another thing very few home gardeners will do: clear out the greenhouse for sanitation. This annual rest period also protects against soil disease. âÂÂWe cover the soil with plastic during this time, and the sunâÂÂs heat takes the temperature up to 50 to 60 degrees [Celsius] and it kills any fungus that causes diseases,â So if they have a once a year sterilizing period they start each year with a ZERO pest load ... good practice if you can do it.

Systemics aren't particularly effective against chewing insects. I suggest that you consider Dipel or Thuricide, which are two trade names for Bacillus thuringiensis Kurstaki, a naturally occurring bacterium strain that only effects caterpillars. There are probably other brands, too. Bacillus products have been around for many many years and are used not only by organic growers but by those who aren't reluctant to use chemicals. It's very effective. Apply the product at the very first sign of caterpillar damage.....which will take some observation on your part. Think how small the caterpillars must be when they first hatch from those tiny eggs. That's when the Btk will be most effective. If you wait until the plant is half eaten, it's too late. Btk will be readily available at any decent garden supply outlet or any online seller of organic pesticides. Be sure to read the label....you want Bacillus thuringiensis var. Kurstaki. There are other Bacillus strains available for the control of other pests. One of the most common caterpillars to be destructive to petunias is the tobacco budworm but others can be culprits, too. Good luck, I don't plant petunias anymore, but I know how quickly they can be munched down to nothing.