Photo by Jacob Winger
Exploring fraise mowing recovery strategies for improved playing conditions
Fraise mowing is a cultural practice that turfgrass managers can employ to enhance playing surfaces. This practice involves removing thatch, organic matter and soil surrounding the turfgrass plant crown. Fraise mowing is an aggressive practice that leaves
areas unplayable for weeks, creating issues for general use and scheduled events. Our objective is to explore methods for enhancing recovery times while improving turfgrass health and playability. Due to the novelty of this practice, there is a lack
of information available to turfgrass managers to confidently implement fraise mowing and take the necessary steps for quick recovery.
Three studies on fraise mowing recovery are being conducted in 2024 and will be repeated in 2025. All three studies are being conducted at Texas A&M University and replicated at Purdue University. The first examines fertilization and mowing depth,
analyzing how different ammonium sulfate rates and reapplication intervals, as well as different depths (0.39 and 0.79 inches/1 and 2 centimeters), can enhance playability and turfgrass quality. The second focuses on the combination of topdressing
and cultural practices (aerification, verticutting, rake), evaluating their impact on recovery rate and playability. The third investigates the use of growth blankets and pigments to accelerate recovery by increasing soil temperatures. TifTuf (Texas)
and Tahoma 31 (Indiana) hybrid bermudagrasses grown on native soils are being used. Data collected will include recovery rate, turfgrass quality, turfgrass shear strength and surface hardness.
Our aim is to provide turfgrass managers guidance on optimizing surface recovery while giving insights into the benefits of fraise mowing. — Jacob Winger (jwinger@tamu.edu), Weston Floyd, Chase Straw, Ph.D., Texas A&M University, College Station;
Jada Powlen, Ph.D., Cale Bigelow, Ph.D., Purdue University, West Lafayette, Ind.
Photo by B.A. McGraw
Silicon fertilization to induce resistance to annual bluegrass weevil
The annual bluegrass weevil (ABW), Listronotus maculicollis, is a major pest of short-mown turf on golf courses across the eastern United States and southeastern Canada. ABW poses significant management challenges, particularly due to its resistance to
many conventional insecticides. Silicon (Si) fertilization has been consistently shown to enhance plant resistance to insect herbivores, specifically in grasses, as they can accumulate high levels of Si in tissues. Si is taken up by plants as monosilicic
acid and is deposited in tissues as amorphous silica gel or phytoliths (SiO2•nH2O). Si deposition confers physical resistance to insect herbivores, as siliceous tissues are tougher and abrasive and thus harder for insects to consume and digest.
Insect herbivores can experience mandibular wear, stunted growth and weakened immunity when feeding on Si-supplemented plants.
Although the negative effects of Si against lepidopteran larvae are well documented, how Si impacts coleopteran feeders such as ABW remains uncertain. Furthermore, we have limited understanding of how feeding on Si-supplemented plants affects insect susceptibility
to biocontrol agents including entomopathogenic nematodes. We conducted glasshouse and field experiments to examine how Si supply to annual bluegrass and creeping bentgrass impacts ABW survival and development and its susceptibility to the entomopathogenic
nematode Steinernema carpocapsae.
Greenhouse experiments revealed that Si fertilization suppressed ABW performance more strongly on creeping bentgrass compared to annual bluegrass. Si reduced ABW egg-laying by 12% to 37% and larval density by 0% to 35% in annual bluegrass with no effect
on the development speed of larvae. Conversely, in creeping bentgrass, Si fertilization reduced egg-laying by 22% to 37% and larval density by 68% to 85% with a retardation in larval development. In field trials, Si supplementation increased Si concentrations
in leaf tissues of both grass species, with mean concentrations rising from 0.37% to 0.47% in control plots to 1.54% to 2.48% in Si-treated plots. While ABW population density in the field was higher in annual bluegrass relative to creeping bentgrass,
the effect of Si on ABW performance was inconclusive.
Our data so far suggest that Si fertilization has a strong negative effect on ABW when feeding on creeping bentgrass compared to annual bluegrass. Thus, Si fertilization could provide a competitive advantage to creeping bentgrass over annual bluegrass
in mixed annual bluegrass-creeping bentgrass fairways when challenged by ABW. — Albrecht M. Koppenhöfer, Ph.D., (a.koppenhofer@rutgers.edu), Tarikul Islam, Ph.D., and Matthew S. Brown, Ph.D., Department of Entomology, and Joseph R. Heckman,
Ph.D., Department of Plant Biology, Rutgers University, New Brunswick, N.J.; and Ana Luiza Sousa, Ph.D., Syngenta Seeds Development — R&D Innovation Center, Malta, Ill.
Darrell J. Pehr (dpehr@gcsaa.org) is GCM’s science editor.