Living the Green Dream

Northeastern Golf Courses Put IPM to Work

Cupcakes, anyone? Daniel Peck checks turf samples for the presence of white grubs. Photo by Dede Hatch

Golf course managers work hard to maintain the beautiful green carpet of turfgrass that players have come to expect. This “flawless” landscape comes at a cost: it’s generally attained through heavy reliance on pesticides, long considered a requirement for acceptable playing and aesthetic conditions.

In recent years, states and localities have begun to pass laws requiring reductions in chemical pesticide use on golf courses. Turf managers need strategies to comply with new mandates, lessen environmental impacts, and continue to attract players in a competitive industry. The Northeastern IPM Center has funded several projects to help them meet these challenges.

Golfers Give IPM the Green Light

The public golf course at Long Island’s Bethpage State Park is a living laboratory where IPM researchers have explored the feasibility of managing turf with few or no chemical pesticides since 2001. Jennifer Grant (NYS IPM Program) leads this ongoing project, which has tested numerous pest management scenarios ranging from conventional to IPM to nonchemical approaches, as well as various cultural practices. Northeast IPM funds supported the project from 2005 to 2007.

Eight years of results have shown that the quality of IPM-treated turf is often as good as that of conventional treatments, though biologically based treatments have not provided consistently acceptable turfgrass.

Meanwhile, environmental benefits have been impressive: a combination of IPM and alternative cultural practices brought up to an 85 percent reduction in environmental impact from conventionally managed greens (as measured by the environmental impact quotient formula).

A crucial measure of success has been the roll of the golf ball, which was not adversely affected under any of the treatment scenarios.

Hundreds of golfer satisfaction surveys have provided the best news of all: on average, golfers rated the IPM putting greens to be good to very good, and not significantly different from conventionally managed greens. When asked about their preferences for pesticide use on public golf courses, half of those surveyed said they want to see “greens kept at reasonably good quality, using pesticides judiciously only when needed”—in other words, they choose IPM. So, as it turns out, good public relations may be an added benefit for courses that adopt an IPM program.

Creative Mixtures Combat Grubs

When it comes to white grubs, turf managers have come to rely on the “preemptive strike,” applying the pesticide imidacloprid to control the pest in its earliest life stages. The reason? Young white grubs are too tiny to target in scouting programs. By the time grubs reach the third instar stage—when they’re large enough to sample—imidacloprid is ineffective at controlling them.

To find a solution, Daniel Peck (Cornell Univ.) tested various biological control products in combination with low rates of chemical insecticides to control third instar grubs, hoping to find new approaches for breaking down their defenses.

Sure enough, Peck found that certain strains of nematodes and fungi, which are harmful to grubs, could be successfully paired with reduced rates of insecticide for late season control. Although alone each tactic is ineffective against large late-season grubs, together they worked synergistically to kill a majority of grubs.

Having identified several promising combinations of products, Peck has leveraged his Northeast IPM funds to field-test these combinations and is now working to find ways they might be incorporated into more successful white grub IPM programs.

Outwitting Weevils

Annual bluegrass weevil is a growing threat to northeastern golf courses. This native beetle can build to astonishing populations that stress or kill annual bluegrass in greens and fairways. Adult weevils invade from overwintering sites in two waves, so a single pesticide application may not control them adequately. Pyrethroid resistance adds to the difficulties of managing these pests.

Richard Cowles (Connecticut Agricultural Experiment Station) is working closely with colleagues and golf course superintendents throughout the Northeast on ways to suppress annual bluegrass weevil. With a new model for pest migration and population fluctuations, Cowles has concluded that it’s preferable to scout and target larvae later in the season. Field trials in Connecticut, New York, and Pennsylvania are helping him fine-tune his approach, which favors spot treatments using pesticides that are less toxic to beneficial predators and to people.

More than 100 golf course superintendents have received instruction in this new approach, and early adopters confirm that it’s working. Educational materials have been published by Golf Course Management magazine and the U.S. Golf Association.