Most “organic” products are effective and may be more beneficial to the environment. For example, insecticidal soap purchased from a garden center is effective for scale, spider mites, and many other insects, and is safe to use on most plants, including houseplants, and does not contain a rinsing agent. Some people make their own from dishwashing liquid. However, dishwashing liquid has a rinsing agent which is desired in rinsing dishes but makes for a very short residual when used on plants and the chemicals may be toxic to some plants. The insecticidal soap purchased from the store is formulated and tested for use as a horticultural insecticide. Be sure to use as directed on the label and only on the plants listed. It has been tested on those plants and found not to be harmful at that rate. I used it last year on all my houseplants before I brought them in for the winter. I also used it to control mites on my dwarf Spruce tree. The main downside of most organic pesticides is the length of the residual and thus may have to be applied more often. Neem oil is approved for organic gardens as a combination insecticide and fungicide. Some brands of insecticidal soap are made from Neem oil so you get the benefit from both.

          Horticultural sulfur is an effective fungicide. It and copper were about the only fungicides available for many years to our parents and grandparents. The only caution is to be careful using these fungicides in the heat of the summer as they burn the leaves. Lime-sulfur is still the treatment of choice as a preventative for peach leaf curl. It can also be used as a dormant spray on other plants to control a number of diseases. In early spring I spray my Peach trees, Pie Cherry tree, Plum trees, and Raspberry canes with lime-sulfur. I also use granular horticultural sulfur around my Azalea, Rhododendron, Blue Hydrangea, and River Birch every year to lower the pH. These plants like a more acidic soil than we usually find in eastern and central Nebraska. Liquid Copper Spray in the spring is the treatment of choice on evergreen trees for Diplodia Tip Blight Sphaeropsis Tip Blight) or Dothistroma Tip Blight. For Diplodia apply the first spray at bud swell. In Eastern Nebraska this is usually around April 24th to May 8th. The second application goes on about 2 weeks later. For Dothistroma Tip blight apply the first spray about mid-May and the second about mid-June

          Corn gluten is an effective organic crabgrass pre-emergent and post-emergent herbicide (weed killer). Use the granular corn gluten as you would any pre-emergent. A liquid spray of corn gluten is also available as a spot weeder. Support our farmers with this natural product that comes as a by-product from processing corn. Many full service garden centers now carry this product and it is organic and natural. The downside is the cost and the length of residual. It is more expensive than non-organic pre-emergent herbicides and has a shorter residual than most so you will need at least two applications in the spring, about six weeks apart. A third application applied in early August will prevent germination of Henbit and Ground Ivy seeds.

          Milwaukee, Wisconsin, treats its sewage and sells it as a fertilizer under the name “Milorganite”. It is lower in Nitrogen than other fertilizers so will not burn your grass and recently was approved for use in vegetable gardens. Corn Gluten products listed above are also an organic fertilizer as well as herbicide. This was developed by Iowa State University.

          Mulch (wood chips, dry grass clippings, straw, and/or compost) placed around your plants and trees is an organic way to control weeds. Mulch, 2 inches to 3 inches deep, can help in weed control as most weed seeds need sunlight to germinate. Do not pile mulch more than 3 inches deep. Mulch also helps keep rain from splashing up on the lower leaves of plants from the soil, thus preventing the inoculation of plants with soil borne diseases. This is especially effective for controlling black spot on Roses and blight on Tomatoes.

          Clematis sometimes gets yellow leaves which looks like iron chlorosis. It may be magnesium chlorosis, or a deficiency of magnesium. A book that Gladys has on Clematis suggests the use of Epsom salts as a good source of magnesium for plants. Place 2-3 Tablespoons around each plant each spring and water in. Many rose growers and tomato growers also recommend this.

          Very soon the Grasshoppers will be starting to hatch. NoLo Bait is a grasshopper suppression bait made from flaky wheat bran which is sprayed with a suspension of distilled water, a sticking agent (Methylcellulose), and Nosema locustae spores. It is non-toxic to humans, livestock, wild animals, birds, fish, or life forms other than grasshoppers and species of insects closely related to grasshoppers. It is very important to understand that NoLo Bait or "Nosema locustae" does not work rapidly. Because grasshoppers are extremely migratory and can move over great distances it is optimal to inoculate your area frequently throughout the season. This will help to spread the infection further and aid in long term control. Nosema may not work as quickly as chemical pesticides, but used correctly, it will have a noticeable impact on populations in the long term. You may observe more obvious results the season after application has taken place than during the season in which you inoculated. This is due to an overall decrease in egg laying capability, and infection of the new spring hatch.

          There are many more good organic controls for weeds, insects, and diseases. Prevention is the best control. For more information contact your local County Extension educator. Also be careful as not all organic controls are safe. More on this in another article.

Copyright 2012