Today's Options In Insect Control: Insect Management

Most turfgrass managers realize the biggest question about insect control isn’t if you will need to treat, but rather when or where or how often. In many areas, the threat from white grubs, chinch bugs, armyworms and a number of other insect pests is frequent and severe enough that turfgrass managers enter each season prepared for battle. This battle is often long and expensive, however, each year additional tools become available for contractors’ use against a range of turfgrass insect pests.

One of the welcome trends observed in turfgrass insect control products has been a shift toward products that are lower in toxicity, considered reduced risk, and in some cases are natural in composition. This move toward such products reflects the demand for such products from society and turfgrass managers alike, but it is also a sign of advances in research and technology.

Research on natural, biological, and organic pest control has produced a number of new options for insect management in turfgrass. In some instances, these new approaches are unique chemistries for conventional pesticides.

NEW GROUPS. One major group of new chemistry has been the increase in products in the class of synthetic pyrethroids. In general, these pesticides have low use rates as compared to other conventional pesticides, low mammalian toxicity, and a broad spectrum of control against surface feeding insects. On the other hand, they have limited activity against some of the soil insect pests (i.e., white grubs), and are relatively toxic to fish. These products, all labeled for use in residential landscapes, include Tempo, Scimitar, Battle, Mavrik, and Talstar.

Many turfgrass managers have found these products to be quite practical and useful due to the low use rates and rapid knockdown of pests. Some are surprised by the higher price, but one must consider the use rate for 1,000 square feet before automatically assuming these products are more expensive to use.

Two newer products directed primarily at white grub control are Merit and MACH 2. Merit reached the market first and attracted interest when the U.S. Environmental Protection Agency provided an accelerated registration and classified it as a reduced risk pesticide. However, the unique chemistry of this product requires that the application be made in a preventive manner. A turfgrass manager cannot simply wait until large third instar grubs are present and then use Merit to remedy the situation. Merit must be used against small, newly hatched white grubs to be fully effective.

One important feature of Merit is its low toxicity to mammals, fish and birds. This is due to the unique chemistry (a class called chloronicotinyls) which affects a nerve site in insects that is very sensitive. Merit also has systemic activity that is somewhat unique for a turfgrass insecticide. We are still learning about all of the options for using Merit against turfgrass insect pests, but this product has been widely accepted by the lawn and landscape industry.

Another product that has received a lot of attention during the past year and also has a favorable toxicity profile is MACH 2. This product is similar to Merit, providing excellent white grub control with relatively low toxicity, and it has a tendency to work best when applied preventively.

The mechanism by which MACH 2 controls insects is much different than for Merit or any other white grub insecticide. MACH 2 stands for molt accelerating compound, which means that it speeds up the normal molting process in grubs. The accelerated growth causes the insect to stop feeding, eventually stressing the insect to death.

Similar to Merit, MACH 2 has low toxicity to birds, fish, earthworms and wildlife and, despite the requirement to be used in more of a preventive fashion than on an as needed basis, it will probably have good success in the marketplace. Such products challenge our traditional concept of integrated pest management where we use pesticides more on an as needed approach when a pest problem threatens the turf.

When other control options (e.g., cultural or biological) are not practical, then a pesticide can be called upon to quickly remedy the problem. Fortunately, in the case of white grubs, many turf managers are familiar with high risk sites for infestations. In areas where problems from white grubs are expected, the use of a preventive application of a pesticide prior to the infestation is not necessarily counter to IPM philosophy. This is particularly true when the pesticides used have favorable characteristics that may justify their use in such situations.

THE NATURALS. Another new product that is classified as a natural product is Conserve SC. This product is in fact the result of a fermentation process involving a soil organism. The fermentation product can be produced commercially and packaged as a readily available product. Conserve SC has many of the desired characteristics of conventional pesticides, such as good shelf life and ease of application.

This product has shown good effectiveness against a wide variety of caterpillar pests of turfgrass. While the spectrum of control is limited to caterpillars, the availability of a natural product for such use is welcomed by many turfgrass managers. The active ingredient, spinosid, is similar to the conventional insecticides Merit and MACH 2 in that it is quite selective and affects primarily only the pest species.

Another natural product that has been around for a long time but that only recently generated interest from manufacturers is Neem. Neem extract from the neem tree that grows throughout the semi-arid tropics contains an active ingredient called azidirachtin. This product acts as an insect growth regulator and immature insects stop growing properly and/or are repelled by it.

New formulations provide a reliable product that is proving effective when used against caterpillar pests if applied while they are still small. Products such as Turplex, BioNeem and Azactin are available for turf and ornamentals. Once again, as is the case with several of the newer products, it is critical that the application be targeted toward the smaller, more immature insects to obtain best results. This means a good scouting and monitoring program and a working knowledge of the pest biology and life cycle is essential.

Another biological product that has been around for many years, yet was never commercialized on a large scale, is the fungal pathogen, Beauveria bassiana. At least one company and possibly a second will have this product available for turf use in 1998. Naturalis-T is labeled for the control of crickets, chinch bugs, and white grubs. There has only been limited testing conducted by university specialists and the exact fit of Beauveria bassiana products is still not clear. Hopefully, more complete data on these products will be available soon to help guide turf managers in the use of these products. It is known, though, that these products are sensitive to light and that application late in the day appears to improve performance.

NEMATODES AND BACTERIA. One final biological product that has been available for years has been the entomogenous nematode products. A variety of products have been on the market for several years and have enjoyed a wide range of successes and failures. The changes in products and companies over the years, as well as inconsistent results and special storage and application requirements, have reduced the popularity and attractiveness of this control technology.

Several species of nematodes are available, and each species is most effective against a particular group of insects. For example, Cruiser is most effective against white grubs. Specific application guidelines for each product are critical for success. Failure to follow guidelines exactly will often result in a complete failure of the product.

The use of various bacteria for insect control has been explored for many years and several products are available, but they received limited use in turf. Several products containing Bacillus thuringiensis, including Dipel, Caterpillar Attack, Javelin and Thuricide, are newer strains that are fairly effective against caterpillars.

A new strain, Bt. Japonensis ‘buibui’ was under development for a number of years and had shown excellent promise as a biological control for several species of white grubs. However, Mycogen Corp. discontinued development of this product in 1996 and there is no new information on any plans for further development. A biological control of Japanese beetle grubs, milky spore or Bacillus popilliae, continues to be available in limited quantities, but grub control is typically less than 50 percent.

SUMMARY. A number of new tools are becoming available to meet the needs of turfgrass managers and help move turfgrass pest management into the next century in an environmentally conscious and cost effective manner. However, this promising outlook for the industry is going to require a renewed commitment to education. First, those of us in the industry need to commit to education concerning all of the tools available for turfgrass insect management. Many of the new products require a very thorough understanding of how they work and the specifics of how to make them work most effectively and in concert with other management strategies. In addition, there is a need for an even better understanding of pest biology to target products toward the most susceptible stage.

Customers also need education about the use of these new products. There must be an understanding of the limitations of certain products, which may include effectiveness against only the smaller stages of a pest and slower activity or control. Improved scouting programs may be required, and the cost of such activities may need to be passed on to the customer.

The advent of new products and strategies for turfgrass insect control is a bright spot for our industry. Research indicates the development of products that meet customers’ needs will continue. Keeping abreast of their development is essential to the maintenance of a profitable business.