Question
I am trying to grow different varieties of lettuce in containers and find there are lots of tiny tan spots all within the leaves themselves.  I'm wondering if they are bugs that just grew into the leaves and died in there so I don't want to eat them. I wanted organic produce so I hate to spray them but I did rinse them with the hose when I saw aphids.    Thanks for any help you can give me.

Answer
The tan spots are caused by dehydration in the areas infected by bugs. The bugs are most likely no longer on the surface of the leaves. Once they suck an area of the foliage dry, they move on to another area. They also do not lodge themselves inside the veins of the foliage.

Two great organic pesticides are pyrethrum and rotenone. Both are plant extracts which are non-toxic to humans and pets, and can be sprayed right up until harvest. They can be purchased separately or as a combination.

For caterpillars, an effective organic control is BT (bacillus thuringiensis), which is sold under the brand name Dipel.  Another good organic solution is MVP II which can be purchased from the site specified below.

Home Harvest, Concern, and Dragon sell these solutions through most reputable garden centers, nurseries, or the Internet.  You can also purchase this product on-line through companies that specialize in organic products. One that I use quite frequently is Gardens Alive.  You can find their website at: http://www.gardensalive.com/

Two homemade solutions that are very effective are insecticidal soaps and garlic spray.  You can purchase either of these at your local garden center, or make them at home.

Soap is a very popular insecticidal control.  I use it myself in combination with ammonia.  Simply mix one tablespoon of regular non-concentrated dishwashing soap and one tablespoon of lemon ammonia to one gallon of water.  Spray it liberally on your plants.  It destroys the digestive tracts of the insects and kills them within a few hours of ingestion.

To make garlic/pepper spray, liquefy 2 bulbs of garlic and 2 hot peppers in a blender ˝ to 2/3 full of water. Strain the solids and add enough water to the garlic/pepper juice to make 1 gallon of concentrate. Use 1 cup of concentrate per gallon of spray. To make a pure garlic tea, simply omit the pepper and add another bulb of garlic. Add two tablespoons of blackstrap molasses for more control.

I hope this answered your question. Please write again if I can ever provide assistance.

Regards,

Mike