Answer: What kind of damage are you seeing on your plants? Are big chunks of the leaves being eaten? This might be done by insects with chewing mouth parts like caterpillars or by slugs. Are there tiny little bugs slurping the juice out of the plant? These might be insects with piercing sucking mouth parts like aphids.
How much damage are they really doing? Are they hurting the plant significantly? If not you might want to look upon the insects as food for beneficial creatures (birds eat caterpillars, lady bugs and lacewings eat aphids) and tolerate a little bit of damage to your plants to feed the beneficials.
If they are doing so much damage that you feel a need to control them, start with the least toxic strategies first. Pick off and dispose of caterpillars, hose off aphids with a strong blast of water. You may want to spray aphids with mild soapy water (1 tsp to 1 tbsp of non-concentrated dish detergent per gallon of water - do not use citrus based soap). Before spraying the entire plant, always spray a few leaves and check the next day for leaf burn.
For more detailed information on what might be happening in your garden right now see the Maricopa County Gardening and Landscaping Web Site - Timely Tips for April http://ag.arizona.edu/~bradleyl/homehort/april.htm
In the left hand column click on "leaves" to explore some of the possibilities.
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