Pacific shoot‐gall disease control in annual bluegrass putting greens using a new formulation of abamectin

Abstract

The Pacific shoot-gall nematode (Anguina pacificae Cid del Prado Vera & Maggenti, 1984) is a devastating pest on annual bluegrass (Poa annua L.) putting greens in coastal Northern California, USA. Frequently used plant protection compounds such as fenamiphos and azadirachtin are either no longer registered or very expensive and have often resulted in nematode suppression at best. A new formulation of abamectin (Divanem ® ; Syngenta, Greensboro, NC) was tested at two rates (0.15 and 0.30 kg a.i. ha −1 ) and two application frequencies (2X vs. 4X) in comparison to fluopyram (Indemnify ® ; Bayer CropScience, St. Louis, MO) applied at the rate of 0.5 kg a.i. ha −1 on three California golf courses: Pasatiempo, Santa Cruz; Laguna Seca, Monterey; and Del Monte, Monterey. Fluopyram showed the best efficacy regarding recovery from and protection against the Pacific shoot-gall disease. Generally, only two applications were required for season-long protection. Four applications of the new formulation of abamectin at the high rate were often necessary to achieve efficacy similar to fluopyram. Overall, abamectin represents another new plant protection tool that offers a treatment alternative for the management of this pathogen. Neither product had much effect on populations of soil-dwelling A. pacificae, spiral (Helicotylenchus spp.), ring (Criconemoides spp.), and root-knot (Meloidogyne spp.) nematodes.