Fall and/or Spring Applications of Granular Dithiopyr and Prodiamine for Crabgrass (DIGSS) Control in Turfgrass Michael W. Melichar, Daniel L. Loughner, Zachary J. Reicher, Daniel V. Weisenberger, and Jeff A. Borger Dow AgroSciences LLC, Purdue University, and The Pennsylvania State University

Fall and/or Spring Applications of Granular Dithiopyr and Prodiamine for Crabgrass (DIGSS) Control in Turfgrass Research Justification –Dithiopyr and prodiamine are labeled for pre- emergent crabgrass control in turfgrass Typical applications occur in spring prior to crabgrass emergence Little research has been conducted with fall application of granular dithiopyr and prodiamine –Fall applications would benefit professional lawn care operators and golf course superintendents allowing time in the spring to complete other required turfgrass management operations

Fall and/or Spring Applications of Granular Dithiopyr and Prodiamine for Crabgrass (DIGSS) Control in Turfgrass Key Question: How do fall and/or spring applications of dithiopyr granule and prodiamine granule compare for crabgrass (DIGSS) control? Trial Locations –IN (Fall 2006 – July 2007 / Fall 2007 – August 2008) –PA (Fall 2007 – August 2008) Methods –Plots; 1.5M X 1.5M –Replications; 3 –Application Equipment; Shaker Bottle or Shaker Table Statistical Analysis –Combined data from three trials –ANOVA with Tukey means comparison test to determine differences between treatment means (p <.05)

Fall and/or Spring Applications of Granular Dithiopyr and Prodiamine for Crabgrass (DIGSS) Control in Turfgrass Key Findings –Fall Applications Dithiopyr – A single fall application and a fall application followed by spring application provided acceptable crabgrass control at rates tested –Fall application followed by spring application did not significantly improve crabgrass control over individual fall or spring applications at rates tested Prodiamine –Fall applications did not provide acceptable crabgrass control at rates tested –Fall application followed by spring application provided acceptable crabgrass control at rates tested

Fall and/or Spring Applications of Granular Dithiopyr and Prodiamine for Crabgrass (DIGSS) Control in Turfgrass Key Findings –Spring Applications Dithiopyr –March, April, and May applications of dithiopyr provided acceptable crabgrass control at rates tested –June application of dithiopyr did not provide acceptable crabgrass control at rates tested Prodiamine –March and April applications of prodiamine provided acceptable crabgrass control at rates tested –May and June applications of prodiamine did not provide acceptable crabgrass control at rates tested

Fall and/or Spring Applications of Granular Dithiopyr and Prodiamine for Crabgrass (DIGSS) Control in Turfgrass Treatment List (All treatments applied on Fertilizer) October g ai/ha October g ai/ha November g ai/ha November g ai/ha November / May fb 280 g ai/ha November / May fb 280 g ai/ha March – 430 g ai/ha March – 560 g ai/ha March – 730 g ai/ha April – 430 g ai/ha April – 560 g ai/ha April – 730 g ai/ha May – 430 g ai/ha May – 560 g ai/ha May – 730 g ai/ha June (No Tillering) – 430 g ai/ha June (No Tillering) – 560 g ai/ha June (No Tillering) – 730 g ai/ha Fall Applications Spring Applications

Parts of a Box-Plot Center 50% Response + Extreme Value 25th Percentile Median Mean 75th Percentile Upper 25% Lower 25%

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Dimension & Barricade Granule Fall/Spring Timing Study Untreated – Indiana (2006 – 2007)

Dimension & Barricade Granule Fall/Spring Timing Study October 15 Application – Indiana (2006 – 2007) (88%) 0.5 lb a.i./A (81%) 0.65 lb a.i./A

Dimension & Barricade Granule Fall/Spring Timing Study November 15 Application – Indiana (2006 – 2007) (89%) 0.5 lb a.i./A (82%) 0.65 lb a.i./A

Dimension & Barricade Granule Fall/Spring Timing Study November 15 fb May 15 Application – Indiana (2006 – 2007) (91%) lb a.i./A (86%) lb a.i./A

Dimension & Barricade Granule Fall/Spring Timing Study March 15 Application – Indiana (2006 – 2007) (65%) 0.38 lb a.i./A (94%) 0.5 lb a.i./A (85%) 0.65 lb a.i./A

Dimension & Barricade Granule Fall/Spring Timing Study April 15 Application – Indiana (2006 – 2007) (86%) 0.38 lb a.i./A (93%) 0.5 lb a.i./A (57%) 0.65 lb a.i./A

Dimension & Barricade Granule Fall/Spring Timing Study May 15 Application – Indiana (2006 – 2007) (90%) 0.38 lb a.i./A (96%) 0.5 lb a.i./A (9%) 0.65 lb a.i./A

Dimension & Barricade Granule Fall/Spring Timing Study June 15 Application – Indiana (2006 – 2007) (56%) 0.38 lb a.i./A (47%) 0.5 lb a.i./A (75%) 0.65 lb a.i./A

Fall and/or Spring Applications of Granular Dithiopyr and Prodiamine for Crabgrass (DIGSS) Control in Turfgrass Conclusions –Dithiopyr –Fall applications and fall application followed by spring application provided comparable crabgrass control to spring applications at rates tested –Prodiamine –Fall applications did not provide comparable crabgrass control to spring applications at rate tested –Fall application followed by spring application provided better crabgrass control than spring applications at rates tested