What do we use and how do we use them? A good question from member.
Firstly we do not use any organic herbicides. I did some experiments about five years ago and found they did not work well. We cultivate, mow or flame weed our weeds.
Lets talk about bugs; we do have some but notable exceptions there are really no problems. I can’t remember when I last sprayed for Tomato Horn worm. In the past cucumber beetles have been a problem but as the years go by they have become just a minor irritation. Why is this? Well I would like to think that the biodiversity of the farm is encouraging a very nice balance between the pest and their natural predators. The natural predators always need a few pest around so we do see them but so long as they do not get out of hand I do not have to intervene.
The big exception is aphids, the continue to be a problem. This spring we have all seen them on the Red Russian Kale. Organic pesticides work only by making contact with the pest. For example soft soap lowers the natural water tension so that water can enter the spiracles of the aphid through which it breathes. Making contact with every pest on the plant by spraying soft soap solution or any other organic pesticide is very difficult. We had a tractor mounted sprayer made for us about 12 years ago. It was described by the local pesticide store as the most sophisticated sprayer he had seen. The reason was that to make the organic pesticides work we had to have many nozzles pointing in all directions at the plant and a high enough pressure and special ‘tips’ so that we misted the material on and it found every aphid hiding on the plant. With this sprayer we use a material called Stylet Oil. It is a mineral oil that as very fine particles smothers the aphid and stops it being able to find feed.
As it is very difficult to kill pests by direct spraying them with organic materials we use another approach. This one is to slow their feeding. Covering what they eat so that they ingest it. We use a material called Ceder Guard. Exactly how it works, I believe, is really not know but the pests do seem to slow down and move on. Another material is GC Mite which is not now being registered for organic use although we can still use supplies on hand. If you have a material you want organic farmers to use use register it with the Organic Materials Research Institute www.omri.org
As for diseases the only material I use is lime sulfur to control peach leaf curl. This can be sprayed at a high concentration at the end of November and mid winter. It works by etching away the protective coating of the over wintering spore of the disease. It also etches away the coating on your protective equipment. Upon application the acid is neutralized so it is safe for the environment but I do not like using it. The only time I use it is just as the buds break when a much lower dose is required. This is fine but this year it was raining when I needed to spray and now I have a bad peach leaf infection on the trees.
To sum up there are organic pesticides but it is much better to create diversity on the farm. It is good to know that when problems get out of hand there are organic options.