We recently received the following question: I am a home vegetable/herb gardener in San Diego.  I have only been growing for three years, so I am still learning.  I tried to grow cauliflower, broccoli and cabbage last cool season and they looked so wonderful.  I harvested them and got ready to cook, and they were FULL of aphids!  What a disappointment.  I spoke to my local nursery, Walter Anderson, and they advised me to “just give up growing cole crops organically.”  Well, I just refuse to believe that!  Can you help me with some tips on controlling aphids on my cole crops here in San Diego?  I'm in Sunset climate zone 23. Thanks, Jennifer Boles

For the answer, we contacted Nick Sakovich and here are this thoughts.

I wouldn't give up. There are some things to do: The two main organic insecticides you can use are horticultural oils, including neem oil, and soap sprays. These will do a decent job. Spraying when you first see the problem, i.e. when the aphid population is low, is best. Other organic insecticides that can be used -- but are more toxic to humans and beneficial insects -- are the pyrethrins (derived from the chrysanthemum flower) and rotenone. One should always read the labels to make sure the product is registered to be applied to that particular crop. When spraying with insecticides, repeat applications are needed since the sprays usually do not control all stages of the insect’s life cycle. Labels usually recommend at least two applications at 5 - 7 days apart.

Other options (click "read more" for rest of article):

I recently had Nick Sakovich come to visit the herb and vegetable gardens we put in earlier this year here at the Ritz-Carlton, Kapalua. Like a lot of new gardeners, I didn’t grow up farming so felt I needed some advice on what I was doing right and wrong (mostly wrong) and couldn’t have found a better person than Nick, who was the farm adviser for the University of California in Orange, Ventura and Santa Barbara counties and ran their master gardener program. Now retired, Nick lives on the Big Island where he gardens on three acres and writes a column for the Hilo Tribune. He came out with his wife for a three night stay, where we filled them with good food in exchange for his help with the garden.

Mostly Nick’s advice centered on the theme of bringing what we’re doing back to the science -- that if you have a scientific foundation for what you’re doing, you’ll be in much better shape.

Here, specifically, are a few of the areas we concentrated on:

The Soil. It’s important to analyze the soil you’re working with so you know what nutrients you’re lacking and therefore what kind of fertilizer you should be using. A specific test for plant pathogenic nematodes can also be performed. Or you can just pull up some susceptible plants like tomatoes and look for knotted or galled roots. The damage is obvious. I’m pretty sure we’re dealing with a lot of root knot nematodes. If you do have them, there are some things to do to manage them; namely plant non-host varieties and species in the infected areas. In regions with warm climates -- lots of sunshine -- soil sterilization is an option. Certain marigold species also help in reducing nematode populations. (Click "read more" for whole article)