Research Updates from Virginia Tech continued
Early Postemergence Control of Crabgrass in Bermudagrass
Untreated plot
By Jeffrey Derr, Ph.D., Adam Nichols, Aman Rana Virginia Tech, Hampton Roads AREC
C
rabgrass is a summer annual grassy weed that can cause major problems in bermudagrass. Not only is there an aesthetic issue for home lawns, but the surface disruption in uniformity caused by crabgrass on bermudagrass golf courses and sports fields is a problem. Crabgrass begins to germinate in early to mid-March on the eastern side of Virginia, and continues through the summer. In the lower mowing heights of bermudagrass, crabgrass germinates before bermudagrass is fully greened-up in spring. Crabgrass can be controlled with preemergence herbicides when applied prior to germination. However, some of the preemergence products can work postemergence if applied to recently-germinated crabgrass plants. In this study, we tested the early postemergence control of crabgrass in bermudagrass using Crew, a combination of isoxaben and dithiopyr in a granular formulation. The granular formulation will allow Crew to be applied using a spreader for even coverage. Crew was tested versus industry standard, sprayable formulations on crabgrass in the 1-leaf stage.
Dimension 2EW, 1 qt/A
Crabgrass Cover (%) Trt #
Treatment
1
Untreated Check
2
Crew
3
Crew
4
Dimension + Gallery
5
Dimension
6
Gallery
LSD P=.05
Rate
34 DAT
76 DAT
134 DAT
19 a
75 a
97
a
150 lb/A
0 b
4 b
9
b
200 lb/A
0 b
0 b
1
d
1 qt/A
0 b
4 b
8
bc
1 qt/A
0 b
0 b
4
cd
31 fl oz/A
16 a
73 a
97
a
4
10
Dimension 2EW, 1 qt/A + Gallery 31 fl oz/A
31 fl oz/A
4
Crew at 200 lb/A provided excellent early postemergence control of crabgrass. Crew at 150 lb/A provided good early postemergence control of crabgrass. This product is an easy to use product that can provide excellent early postemergence crabgrass control.
Crew 150 lb/A
Crabgrass in 1-leaf stage at time of application.
Crew 200 lb/A Gallery 31 fl oz/A
28 | VIRGINIA TURFGRASS JOURNAL January/February 2021 www.vaturf.org
