"There's concern about exposure to pesticides," said Shetlar. "Residents are calling for minimizing use of pesticides, and when they are needed, to use the least toxic available. With insecticides, we have some new technology that allows us to meet those expectations."
Sports turf managers fighting bugs by going green
Not surprisingly, more turf managers are interested in going green. That’s why Dave Shetlar, Ohio State University Extension, will present “Cost Effective and Earth Friendly Insect Control” at the 15th annual Ohio State Sports Field Short Course, Feb. 9-10 in Columbus.
“There’s concern about exposure to pesticides,” said Shetlar, also known as the “Bug Doc.” “Residents are calling for minimizing use of pesticides, and when they are needed, to use the least toxic available. With insecticides, we have some new technology that allows us to meet those expectations.”
In his talk, Shetlar will offer details to grounds staff, coaches, contractors, facility managers and other participants interested in athletic field management. He’ll specifically compare the use of neonicotinoids — nicotine-based insecticides that affect insects’ central nervous system — with a newer chemistry, anthranilic diamides.
When neonicotinoids (pronounced neo-nick-i-tin-oids) came on the market, they were seen as less toxic alternatives to some other insecticides, but their real advantage was that they provided a long window of opportunity for grounds managers to use them, Shetlar said. Instead of having to apply insecticides between mid-July and early August — times when most sports fields are in heavy use — they could be applied as early as May. Even though neonicotinoids are classified as having medium or low toxicity, the ability to apply them when children, teens or even highly valued professional athletes aren’t scheduled to be on the field was a big advantage, Shetlar said.
However, neonicotinoids have been linked with the precipitous decline in the honey bee population, Shetlar said. That alone is a good reason to investigate the new class of insecticides, anthranilic diamides. DuPont is the first company to develop one of these insecticides, under the trade name Acelepryn. Anthranilic diamides affect how calcium works in the muscle tissue of insects and other arthropods, including centipedes and white grubs, giving the bugs severe muscle cramps — effectively undermining their life cycle. Since calcium is used so much differently in humans and other mammals, anthranilic diamides are the least toxic type of insecticides available — “practically nontoxic,” Shetlar said.
In addition, “Neonicotoids are worthless on caterpillars,” Shetlar said. “(But) this one is great on caterpillars. And we can apply it any time from the first week of April and get season-long billbug, white grub and caterpillar control.” Although the product was initially much more expensive than the alternatives, the price is coming down, he added.
Another factor to consider, Shetlar said, is the type of turfgrass planted on sports fields. A former graduate student, Doug Richmond, examined the use of endophytic turf grasses — grasses that contain a fungus between the cells of the grass blade. The fungus is harmful to livestock, so decades ago, plant breeders developed a tall fescue with the endophyte removed. “It’s a wonderful resource for livestock, but insects love that grass,” Shetlar said.
Dwarf varieties of tall fescue that contain the fungus are available for athletic fields, and as a doctoral student, Richmond found that planting turfgrass containing 30 to 35 percent endophytic tall fescue killed off insect pests. He discourages planting more than that proportion to reduce the risk that insects would become resistant to the toxins that the fungus produces.
“From that research, I recommend this technique to sport turf managers for when they reseed. These tall fescues have a deep root system, are less susceptible to grubs and can tolerate dry periods longer. It’s a long-term fix rather than constantly applying insecticides.”