Research Updates from Virginia Tech continued
Evaluating the Interaction of Plant Growth Regulators and Lance Nematodes on Creeping Bentgrass Putting Green Health By M. Aaron Tucker, Jon D. Eisenback, and David S. McCall, Ph.D.
The
FIGURE 1. The male (left) and female (right) lance nematode (Hoplolaimus galeatus) under magnification. Photo credit: Jon D. Eisenback.
FIGURE 2. Suspected lance nematode damage often shows up in the clean-up lab of many creeping bentgrass putting greens. Photo credit: Aaron Tucker
lance nematode, Hopolaimus galeatus, is a plantparasitic nematode (PPN) that is commonly identified as problematic in warm-season golf course putting green samples. We have noticed an increase of high lance populations in Virginia’s cool-season putting greens with limited options of control. Plant growth regulators (PGRs) are commonly used in putting green management for greater surface consistency and reduced mechanical stress. Numerous golf course superintendents who have used PGRs either currently or in the past have suggested to us that creeping bentgrass damage associated with high counts of PPN may be related. To date, there is no information available to validate or refute this relationship. Finally, the product fluopyram is a great management option for most PPN but has little to no efficacy against lance nematodes. Exclusive use of this product may lead to problematic populations of lance nematodes in putting greens. The objectives of this work were to determine whether the addition of fluopyram to PGR applications impact creeping bentgrass quality and how fluopyram combined with PGRs impact lance nematode populations. A 5x2 factorial study was conducted at five locations across Virginia for 16 weeks to assess the impact of fluopyram, PGRs, and their interaction on putting green quality and nematode populations over time. The five locations consisted of Heron Ridge Golf Club (Virginia Beach), Golden Horseshoe Golf Club Gold Course (Williamsburg), The Club at Viniterra (New Kent), The Foundry Golf Club (Powhatan), and The Club at Glenmore (Keswick). Five PGR treatments consisted of Primo Maxx (trinexapacethyl, 0.125 fl oz/1000 ft2, 14 days), Anuew (prohexadione calcium, 8 oz/acre, 14 days), Cutless (flurprimidol, 24.6 fl oz/acre, 28 days), Trimmit (paclobutrazol, 10 fl oz/acre, 42 days) and a no PGR control. Fluopyram was applied every 28 days at 0.2925 fl oz/ 1000ft2 and compared against a non-treated control. Assessments were collected every 14 days and consisted of visual estimations of creeping bentgrass quality, % phytotoxicity, and % visual damage, along with aerial image analysis. Percent phytotoxicity was
FIGURE 3. Field testing location in mid-summer immediately after core removal for nematode and root sampling. Photo credit: Travis Roberson
24 | VIRGINIA TURFGRASS JOURNAL January/February 2022
