BIOLOGICAL PEST CONTROL: Biological Basics

While insects and parasites are the problem for lawn care operators (LCOs), other organisms might be able to help LCOs combat pest infestations. Some green-industry professionals are currently experimenting with these biological controls as pesticide alternatives and/or additions.

Some of the interest in biological controls stems from municipalities passing restrictions on traditional pesticides. "In some areas like New York, New Jersey and Maryland, there are some restrictions that have forced service companies to quit using the standard pesticides and fertilizers that they’ve been using and switch to either biologicals or bio-based products," explains David Shetlar, associate professor of urban landscape entomology at Ohio State University in Columbus. "Because of regulations, we’re going to see that more and more."

DO THEY WORK? From a lawn care operator’s perspective, biological pesticides often don’t make business sense. "Most of what I call traditional landscape management firms are not using these," Shetlar explains. "They use the tried and proven insecticide products that they know will perform at rates that are on the labels, and they don’t have to worry about storage and fresh products."

In general, biological pesticides have shown to be less effective and cost more than traditional pesticides, according to Shetlar. With pesticides, contractors can typically expect 90 percent or better control, he says, opposed to biologicals, which may provide 50 to 70 percent control. Upfront costs are less for biologicals, but in the long run the necessary multiple applications result in higher overall expenses, Shetlar explains.

"We’re talking about products that have less consistency in their performance, so you have a trade-off," he says. "If you’ve got a product that costs you $20 to apply and it offers 100-percent control, it’s almost equivalent to a product that costs $15 to apply, but is only 50 to 60 percent effective. Biologicals are not that expensive. The expense comes in care of application and call-back frequency."

But Don Taylor, president of Lakeland, Fla.-based Poulenger USA, predicts that chemical and biological pesticides will be running neck and neck in the near future when it comes to efficacy. "Most of the chemicals aren’t on the market anymore," Taylor says. "The one-application stuff is gone. Because of environmental concerns, many active ingredients today are not as potent."

Biological controls cannot be 100-percent effective because Mother Nature won’t allow it, explains Cozette Hadley, business unit manager of Ames, Iowa-based biologicals manufacturer Becker Underwood. If biological agents were 100-percent effective, they would lead to extinction of the targeted pest, she says.

On the plus side, bio-pesticides are relatively harmless to people and pets, according to Shetlar. "That’s the real reason why municipalities and anti-pesticide groups want biologicals used," Shetlar says. "They’re virtually non toxic to anything but the target pests. Many biological controls only work on cold-blooded insects and cannot grow in temperatures above 95 degrees."

Also, shelf life for biological pesticides is not much different than many pesticide treatments. Some, such as nematodes, needs to be used immediately while the bacterial and fungal products might last several years, Shetlar says.

INFECTIOUS TREND. To some, the thought of biological pesticides conjure up images of swarming ladybugs or beetles that become more of a nuisance than a solution. But most success with biological controls has been realized with smaller parasitic organisms or bacteria that infect and kill the targeted pest.

Bacillus thuringiensis (BT), which is a bacterium commonly found in soils, is the most popular bio-based control used by technicians because it’s easy to apply, Shetlar explains. BTs are mixed like regular pesticides and can be applied with the same equipment. Also, they don’t require much post-application care and have a shelf life of two or more years. BTs are not considered true biological controls because a protein crystal toxin released by BTs produce the desired effect. True microbial biological controls grow and propagate within the insect’s body.

The BT toxin kills certain insects by creating holes and eating away at their gut lining. There are 50 to 60 different strains of BTs that are commercially available, Shetlar says. For commercial uses, they’re typically produced in laboratories in large fermentation tanks and then sold in a powder form. Some applications may be mixed with a medium, such as molasses that provides food for the bacteria and can also act as a fertilizer for the lawn, Taylor says.

Though BTs are becoming increasingly popular in bio-based control, contractors still prefer traditional pesticides because one BT strain is not effective against multiple pests, Shetlar says. In addition, the bacteria are only effective during early stages of development, which makes control more difficult.

"Most of the BTs are comparable to standard pesticides in cost, but they are one-shot wonders," Shetlar explains. "In other words, they only kill one or two target pests. Most lawn care operators prefer a pyrethroid or some other pesticide that will take out a wider range of pests."

In addition to cost and effectiveness issues, not many people are trained to properly apply bio-pesticides, which also makes the products less attractive to contractors, Shetlar says.

WORM FOOD. Another biological control on the market are beneficial nematodes. Nematodes are microscopic worms that can be used to control a variety of insects in their larval stages, including sod webworms, southern and tawny mole crickets, several species of beetles and white grubs.

Nematodes work by entering the insect through the mouth, anus or breathing pores and then releasing a bacterium that kills the insect and reproduces inside the dead organism’s body, creating a new population of nematodes. These tiny creatures are beneficial because of their ability to provide continuous control by reproducing and creating more nematodes, Hadley says. And like other biological controls, nematodes don’t pose any contamination threats due to water runoff. And areas where nematodes have been sprayed can be used immediately.

One such nematode is Steinernema scapterisci, which is primarily used in the Southeast to control mole crickets. It’s typically applied by first irrigating the affected area with ¼ inch of water and then mixing one billion nematodes in 80 to 100 gallons of water for each acre, according to Becker Underwood product directions.

Good Nature Organic Lawn Care, Cleveland, Ohio, uses a similar formula to control white grubs for its residential customers, says Owner Alec McClennan. The company, which McClennan started in 1999 as an alternative to chemical lawn care, has averaged 80 percent growth in the last three years using its chemical-free approach. The company uses the nematode species Heterorhabditis marelatus because it’s more cold tolerant than other types, McClennan says.

When applying nematodes, McClennan says he usually waits until late afternoon or early evening when the sun isn’t as bright because the nematodes are vulnerable to sun damage. McClennan also refrigerates the nematodes prior to use because they are temperature sensitive. He then mixes approximately 2 gallons of water and sprays the area with a regular tank sprayer.

The results have been positive, according to McClennan. "We’re not doing any studies to see what percentage are killed, but we’re confident that enough of a percentage is dying to keep lawn damage from being evident," he explains.

Under ideal conditions, most nematode products will take between two and five days to kill most insects, according to the Ohio Agricultural and Research Development Center in Wooster. Soil temperatures above 90 degrees can be lethal to the nematodes and temperatures below 50 degrees will slow their activity.

Another factor that can affect efficacy is mixing the nematodes with pesticides. McClennan suggests that contractors who are mixing nematodes with pesticides check to make sure the combination is compatible because some pesticides will kill the nematodes. Contractors may want to test a small amount of nematodes to see whether they survive the mixture, he recommends.

McClennan has never used chemical pesticides but estimates that nematodes cost about 1.5 times more. The nematode product costs between $4 and $5 per 1,000 square feet to apply, according to McClennan. So he prices the service similar to pesticide applications.

For instance, if the pesticide product costs $10 and a contractor is selling the service for $50, that contractor may want to raise the price to $55 if the biological costs an additional $5 to purchase, he says.

LOOKING FORWARD. Despite some dire predictions for the pesticide industry, chemical-based products are still the pest control applications of choice for most lawn care operators. While sweeping changes are being forced in Canada – primarily Quebec where 2002 legislation banned most non-agricultural-use pesticides by 2005 – U.S. lawmakers haven’t acted as quickly.

And because of the higher costs, the bio-pesticide market in the U.S. has been limited to more upscale clients, according to Shetlar. "These customers really don’t care how much it costs," he explains. "They say do it, and we’ll pay the bill, and don’t apply any toxic poisons that might potentially poison my pets or kids. Because of such customers’ perceptions, there’s now a niche group of the service industry that’s beginning to deliver to that department."

Good Nature’s clients are "all over the board," McClennan says. "I think people are becoming more sensitive to pesticides, and they’re looking for options where they don’t have to worry about the safety of their family."

But Shetlar says under current standards biological controls don’t hold enough advantages over traditional pesticides for lawn care technicians. However, with increasing pesticide regulations, biological controls may pick up steam, he says.

However, bio-pesticides may not be the only option for technicians trying to gain a slice of the environmentally conscious market. In the long term, Shetlar foresees more contractors designing pest-resistant landscapes.

For instance, instead of planting disease-prone silver maples, technicians may opt for Norway maples, which have strong wood systems and are less susceptible to fungal diseases, Shetlar says. Or when dealing with lawns, contractors may suggest clients install turf-type tall fescue lawns, which are more resistant to certain insect infestations than Kentucky bluegrass, according to Shetlar.

"I see there’s going to be a real change in the industry," Shetlar says. "My long-term prognostication is more of the service industry will move from the pay-for-application routine to becoming more of a technical-expertise service. That is, when you hire us, we’ll come in and consult with you about what you want your landscape to look like, and we’ll actually change plant material."