Cost is only one factor
Choosing pest control products is a multifaceted decision-making process. Factors involved include product application training, equipment, availability, need for adjuvants, odor and possible incompatibilities with other products in a tank mix.
Unfortunately, product cost is often the first consideration that inexperienced lawn care operators and grounds managers consider. Wading through the selection process isn’t easy and should be done following a careful analysis of all available information.
Residual and repeat treatments
Every pest control product has the capacity to kill target pests. However, products differ in the length of time they remain effective. For some pests, a short window of vulnerability exists due to the natural life cycle of the organism. Pine needle scale and pine sawflies are good examples; insecticide applications are only effective during a two-week period at the proper life stage of the insect. For scale and sawflies, short residual formulations such as horticultural oils and insecticidal soaps offer efficacy without the need for residual activity. If applied at the peak of vulnerability, most sawfly or scale infested trees can be effectively treated with a single application. Other pests, such as lilac/ash borers, are active over a much longer time, and often require multiple applications with longer residual insecticides.
Labor costs are part of the pest management decision-making process. Diagnosis of the problem, mixing time, adding product enhancers (crop oil concentrates, pH adjusters or surfactants), rinsing out tanks and laundering applicator clothing all cost money in terms of the salary paid to the people performing these necessary steps.
Insects or other pests that develop resistance to pesticide products cost money. As pesticide resistance develops, you will need to use more product to achieve to same level of pest control, and callbacks will become more frequent. To reduce the risk of pesticide resistance, always observe treatment threshold levels; i.e., treat only when necessary. When treatment is required, select the appropriate pesticide product (active ingredient and formulation) for the job and apply the product according to label instructions.
Potential for environmental damage
The cost of damage to the environment is another one to consider. In general, products that have the most capacity to cause harm to the environment are ones that have high initial toxicity, long residuals and that kill a wide array of organisms.
The capacity to kill a broad spectrum of organisms has long been an issue within spider mite control. For every undesirable mite species, there is a beneficial one as well. Materials that kill both beneficial and pest mite species are problematic because pest mites are usually able to rebound much sooner after a pesticide application than their beneficial cousins.
Finally, as hard as we try, it’s nearly impossible to keep every drop of pest control formulation on your customer’s lawn, tree or shrub. When applied on windy days or with the inappropriate spray equipment, pesticides can find their way to the street, down the storm sewer and into lakes, streams and groundwater. As you choose pest control product options, consider their potential to move off-site and cause environmental harm.
One option is to take advantage of biorational products. In general, these materials remain active in the environment for a shorter time than conventional synthetic organic insecticides, and are only slightly to moderately toxic to humans, pets, wildlife and other nontarget organisms.
Most grounds managers are aware of the effectiveness of products containing Bacillus thuringiensis (Bt). Various strains and formulations of this bacterium continue to play an important role in insect control in the turf and ornamental market. While Bt products generally pose little environmental risk, they may need to reapplied with each new insect outbreak.
Horticultural oils and insecticidal soaps are also available for control of soft-bodied pests including whiteflies, aphids, mealybugs, caterpillars and spider mites. An attractive feature of these products is that they are essentially nontoxic. This can be a powerful customer relations tool: effective results with low environmental risk.
Finally, it should be noted that some of the newer synthetic organic insecticides, such as chlorantraniliprole (Acelepryn), offer many of these same toxicological and environmental benefits.
Consideration of effectiveness
With all these issues in mind, the best approach could be to start with a consideration of effectiveness first, then proceed accordingly. For example, let’s say that the top three recommended products for control of insects in turf cost about the same and have similar residual activity. However, differences exist in terms of the spectrum of insect species that are effectively controlled. Because effectiveness is the bottom line, one should select a product that maximizes pest control while minimizing negative environmental impacts.
Price is a factor
Low-cost products are advantageous for the obvious reason: they require a lower initial outlay of cash. However, product cost should only be one of the factors you consider when selecting a pesticide. Efficacy, toxicity, availability, ease of application and environmental impacts must also be taken into consideration.
John C. Fech is a horticulturist, certified arborist and frequent contributor located in Omaha, Neb. Frederick P. Baxendale is a professor and extension entomologist with the University of Nebraska-Lincoln.