Wildflowers bring in beneficial insects
This original post was written by Adam Dale, PhD and published on Golf Course Management Magazine in February, 2020. Click here for more!
In recent years, an increasing number of golf courses have repurposed out-of-play acreage to reduce irrigation, mowing, pesticide applications and other maintenance inputs that require considerable time and money. As a result, out-of-play areas have become naturalized roughs, wildflower plantings and monarch waystations, many of which are focused on conserving insect pollinators, which increasing evidence shows are declining around the globe.
This is important, because insects pollinate more than 75% of flowering plants. Although pollinator decline is caused by multiple factors, habitat loss and fewer flowering plants are part of the problem (6). Fortunately, a 2019 survey by the National Recreation and Park Association found that 95% of the American public favors designated areas that support pollinators.
Researchers like those in the lab of Dan Potter, Ph.D., at the University of Kentucky have demonstrated that wildflower habitats on golf courses can provide valuable native bee conservation while also reducing golf course maintenance inputs (4, 5). Despite this, it can be difficult to transition to a new way of creating and maintaining space on a golf course without convincing evidence that doing so provides business value. Over the past three years, my lab at the University of Florida has been working on identifying other benefits that out-of-play wildflower habitats may provide for the golf industry.
Pollinators do more than pollinate
Flowering plants attract not only bees but also predatory and parasitic insects that primarily feed on plant-feeding insects and supplement their diets with pollen and nectar. For example, specific flowering plant species, including shrubby false buttonweed (Spermacoce verticillata), partridge pea (Chamaecrista fasciculata) and white Pentas lanceolata attract the Larra wasp (Larra bicolor), a parasite of mole crickets in the southeastern United States (1, 9). The presence of these plants increases natural control of mole crickets up to 650 feet (~198 meters) away from where they are growing (9).
Mole crickets may not be a problem in your area, but what about white grubs or caterpillars like armyworms, webworms and cutworms? What about armadillos, raccoons, moles, skunks or birds on the hunt for six-legged protein just beneath the soil surface or in the thatch? If any of these organisms are a concern, flowering plants in out-of-play areas on the course may help.
Thread-waisted wasps (in the Sphecid family) and Tiphiid wasps are two diverse groups of insects attracted to a variety of flowering plants that also hunt white grubs that feed on turfgrass roots (10). Once a grub is found, the wasp injects it with neurotoxins and lays an egg on its paralyzed body. Still underground, the wasp egg will hatch into a larva that gradually eats the grub alive and eventually emerges from the soil as an adult wasp on the hunt for more white grubs.
Potter wasps and mason wasps (both in the subfamily Eumeninae) supplement their diets with flowers, but are common predators of caterpillar pests. These insects fly around on the hunt, snatching caterpillars out of the turf and bringing them back to feed to their offspring. Increasing the number of these wasps leads to greater caterpillar control in fairways and reduces the likelihood of caterpillar outbreaks (2).
Examples of these National Geographic-like interactions between insect predators and their prey can be fascinating, but what can they ultimately mean? A recent economic analysis found that the parasites introduced to control mole crickets have substantially reduced mole cricket populations in pastures and have saved the Florida cattle industry about $13 million per year since their introduction in the mid-1980s (8).