Granular Formulations of Sodium Azide for Nematode Control on Existing Bentgrass Putting Greens.

Granular formulations of sodium azide (NaN3) are being evaluated for their nematicidal efficacy in established turf.  Azide salts were impregnated on a porous ceramic (fired illite clay) granular carrier.  Preliminary studies conducted at Auburn University have shown that sodium azide reduces nematode populations in established turf and root lengths have been increased.  It has not been determined if the nitrogen from the Na azide (~46%) or the reduction in the nematode populations are encouraging root growth. The objective of this study was to determine if nitrogen from Na azide or urea contributed to enhanced root growth and reduced nematode populations.  Studies were conducted in 2006 and repeated in 2007 at Grand National Golf Club in Opelika, Alabama on a sand-based ‘Dominant’ creeping bentgrass (Agrostis palustris L.) putting green.  A randomized complete block split plot design was used with 4 replications.  Sodium azide was applied to the entire plot and urea was applied to the split plot.  Treatments included 0, 5.6, 11.2, and 16.8 kg ai/ha of Na azide and 10.8 kg ai/ha urea (46-0-0).  Treatments were applied three times. Ring nematodes (Mesocriconema spp.) were present at potentially damaging numbers prior to application.  After the third application, nematode populations decreased with increasing rates of azide.  Root lengths increased in treated plots compared to non-treated controls. There was no significant difference in plots treated with Na azide plus urea and those treated with Na azide alone.