This installment on the discussion of integrated pest management (IPM) begins with the premise that challenges have emerged as we have new products that have a more favorable environmental profile but might need to be applied in a more preventive manner. We pick up with that concept in part two and look further at newer chemistries and how they fit into what we do each day.

Quick Tip

I think it is important that we not overlook the significant differences in the toxicities of today's modern insecticides. If we go back just 10 to 12 years ago, we were using products that had oral LD50 (lethal dose to 50 percent of the test population) to rats and birds that were measured in single digits. The lower the number, the more toxic the compound. A product with an LD50 in the single digits (kilograms/milligrams) is toxic. This included such household insecticides as diazinon. Over the past 10 years, we have seen the emergence of products that are no longer in the single digits. In fact, they aren't even measured in double digits, but rather in hundreds units and a few of them in the thousands. This is a dramatic change in the toxicity of the insecticides we were applying to the turfgrass. Insecticides under development at this time continue that trend and are pushing towards LD50s measured above 10,000. Additionally, the newer products tend to be applied at much lower rates of active ingredient per acre.

A new addition to the insecticide market has further challenged our approach to IPM and the idea of treating only when necessary. Recently, Bayer Environmental Sciences and FMC Corp. released a product called Allectus. This product contained the active ingredients of two popular insecticides Talstar and Merit. There are several perceived benefits to this product that include its broad spectrum of control that has the potential to control both surface and soil insect as did some of the older, more toxic chemistries, such as diazinon.

While the concept of a more broad-spectrum insecticide, such as diazinon, being back on the market might sound very attractive to us, there are a couple of things we should keep in mind. First, broad-spectrum control historically meant a higher level of toxicity to unintended organisms in addition to insects. This could include aquatic organisms, birds, people and pets. This was a characteristic that companies have worked hard to get away from. We should remember that diazinon uses were severely curtailed and eventually eliminated a number of years ago because there were numerous documented cases of bird kills, particularly on golf courses. While we don't want to regress environmentally to attain broad-spectrum control in our products, some characteristics of the older products are still viewed by turfgrass managers as being very favorable.

Fortunately, when we combine two products that have modern chemistries to obtain a broader spectrum of control, such as addressing surface-feeding and below-ground insects, we don't necessarily increase the hazard or risk. If the two insecticides used in the combination product have favorable environmental profiles, then it is quite likely that the overall concern won't be any greater than that of the product's individual characteristics. This is important to understand as Allectus is one of several combination-type products we are beginning to see in the marketplace.

A second consideration that concerns some people about using combination products is that in some instances, you might be applying two active ingredients and only getting a benefit from one of them. In other words, it might be viewed as a wasted application or simply overkill by others. How often do you have two insects causing a problem in one location? Well, it can and does happen as I have seen fire ants, mole crickets, white grubs, and other insects all pose problems at the same time in one area.

A combination product is going to cost more than a product that contains only one insecticide. Therefore, the vast majority of turfgrass managers are going to take a long, hard look at such products and ask the question as to whether or not they are getting additional benefit from the use of such a product. The answer in some instances will probably be "no", and another, less-expensive product likely will be selected.