Insect control plays a major role in the success of our plants this time of year.
Just when our prized plants and landscapes start to excel, invariably, insects join the party and take their share. Insect identification plays an important role in choosing the right method to control insects.
Using the wrong insecticide can cause more damage than good. There are a few things to think about when selecting insecticides. If physical removal of the insect is not an option, choose insecticides that are either plant based or made from naturally occurring products. A few examples are Bt, spinosad and insecticidal soap.
Bt is short for Bacillus thuringiensis. Bt is a soil dwelling bacterium that, when ingested by a larval stage worm, reacts with the cell lining in a insects gut and paralyzes the digestive system. Without the ability to digest and feed, insects will die within a day or two. This product is very effective but does have some limitations.
Bt will degrade naturally with sunlight and is washed off the leaf surface by rain or watering. This will result in a shorter time frame between applications to ensure coverage and activity. However, the major advantage is that Bt is nontoxic to people, pets and wildlife. This is beneficial for use on food crops or in other sensitive sites where pesticide use can be a problem.
Spinosad (Saccharopolyspora spinosa) is also a soil dwelling bacterium. Spinosad is relatively fast acting. Once the bacterium is ingested, the nervous system of the insect is sent into overdrive and will thus cause death. Spinosad is both a nerve poison and a stomach poison, so it kills pests that it contacts and those that consume it on the foliage they eat. The insect dies within one to two days after ingesting the active ingredient.
This product works on many different types of insects (caterpillars, flies, thrips and beetles) but most beneficial insects are spared. This means that you may need to spray less often if you use this type of material. The natural enemies will be preserved and should help moderate pest populations later in the season.
Insecticidal soaps work best on soft-bodied insects such as aphids, mealybugs, spider mites, thrips, and whiteflies. Insecticidal soaps work only on direct contact with insects. The fatty acids disrupt the structure and permeability of the cell membranes of the insect. Thus, the insects' cell contents leak from the damaged cells and the insect quickly dies.
The insecticidal soaps can be either purchased at home and garden centers or nurseries. However, if you like to do-it- yourself, you can make your own soap and water solution and save a little money in the process. Do not use soaps that contain a degreaser. The degreasers will damage the leaves of the plant.
The degreaser may cause leaves to be deformed or discolored, or even die back. In addition, it is best to be mindful that soaps that advertise as a concentrate will need to be diluted much more than simple soaps. More than likely, the generic soaps are a good choice. Another good choice would be to use a soap that contains a citric acid.
The acid benefits the effectiveness of the solution by increasing irritation of soft bodied insects. Regardless of what soap product is used, sprays are always applied diluted with water and typically at a concentration of two to three percent.
Insect control can leave you in dismay when you visit a local box store or nursery. The sheer number of chemicals that line the shelves can be discouraging. With a little research, you can choose a product that is going to have the desired result for your situation.
Keep in mind to read the label on products you purchase.
The label states all the information that is needed to use the product safely. The label will also state the type of equipment that should be used and what insects are controlled with the particular product.
The chemical world provides the tools we utilize to combat the issues we face with insects, however; with a little planning and education we can choose products that are just as effective and have less impact on the environment.
Michael Potter is a horticulturist with the Texas Agrilife Extension Office in Nueces County. Readers may contact him at 767-5217.