Question
I am a new gardener in Seattle, WA.  I planted butter lettuce this year which has been growing beautifully (due to the abundant rain this late spring/early summer period) but when I checked on it the other day, there were holes all over the leaves.  Something is eating away at my lettuce!  While I have found several snails in the yard, I don't think they're the ones destroying my lettuce because there's no silvery slime and the holes are pretty small (1/8 inch in diameter).  What could be eating my lettuce and how do I fix this problem?  Any help would be appreciated!

Answer
It sounds like it could be any of three flying insects, including flea beetles, whiteflies, or aphids. Regardless of what the insect is, the treatment options are the same.

Two great organic pesticides are pyrethrin 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.
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 ?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.

Finally, you can apply oil sprays, also known as dormant sprays, that are organic and break down very quickly.  Oil not only kills live insects, but also suffocates their eggs, reducing future infestations.  These also can be purchased at your local garden center or through Gardens Alive.

Slugs can be very hard to control. I am happy to say that I抳e finally discovered an effective deterrent.  It is a product sold by a company named Gardens Alive, and is called Escar-Go.  Although it is a pesticide, it is organic, and is therefore non-toxic to humans and pets.  It also stays active and solid even after a heavy rain.  Just sprinkle small amounts around each plant, and reapply every 10 days.  In case you抮e interested, click on the attached website and search for Escar-Go.

http://www.gardens-alive.com

If the area is large, making this product impractical, try spraying the soil with an ammonia solution.  Mix one tbs. lemon ammonia and one tbs. of non-concentrated dishwashing liquid per gallon of water. You抣l need to apply this solution twice per week, and preferable in the early morning hours when slugs are most active.

Recent studies have also showed that slugs are deterred by coffee grounds. Many gardeners apply used coffee grounds to their soil as an organic amendment. These same studies have shown that plants with old coffee grounds sprinkled around them have 80% fewer slugs than those not treated. It also has shown that the coffee grounds kill young slugs. They suspect it is the caffeine, but they are still researching the actual cause and effect.

I hope this solves your problem.  Please write again if you need more assistance.

Regards,

Mike