Evaluation of a new herbicide, Showcase, for preeemergence weed control in nursery container crops.

Showcase is a new herbicide just released from Dow AgroScience. The currently used and popular herbicide, Snapshot 2.5TG, contains the active ingredients isoxaben (0.5%) and trifluralin (2%). The new Showcase herbicide contains the same ingredients but with the addition of oxyfluorfen. The amount of each active ingredient has also changed to: trifluralin (2%) + isoxaben (0.25%) and oxyfluorfen (0.25%).


This experiment was designed to compare efficacy of Snapshot and Showcase to several granular preemergence herbicides for control of common container weeds. Each weed species was evaluated separately. All weed species were inoculated by placing 20 weed seeds on the container surface (seeds were collected and counted earlier).

One gallon containers were filled with 100% coarse Douglas fir bark on May 9, 2005. Bark was amended with 1.5 lbs/yd3 of Micromax and 12 lbs/yd3 Osmocote 18-6-12. Containers were placed on a gravel container pad in full sun. All plants were irrigated overhead with approximately 1/2 inch water/day split in two equal cycles. Herbicides listed in Table 1 were applied on May 26, 2005. One week after potting and herbicide application, containers were over-seeded with 20 seeds from one weed species.

Results and Discussion

Results for each weed species are separated below. Click on the image or the weed name to see herbicide trial results. Click on the words 'Identify this weed' to see additional photos of each plant.



Table 1. Herbicides compared to Showcase and Snapshot for weed control in containers.
Herbicide Active ingredients
Rate (lb/acre)
Showcase oryzalin+oxyfluorfen


Snapshot trifluralin+isoxaben
Snapshot trifluralin+isoxaben
Rout trifluralin+isoxaben
OH2 oxyfluorfen+pendimeth.
Ronstar oxadiazon
BroadStar flumioxazin
Bittercress (Cardamine hirsuta) Identify this weed
Prostrate spurge (Chamaesyce maculata) Identify this weed
Common groundsel (Senecio vulgaris) Identify this weed
Creeping woodsorrel (Oxalis corniculata) Identify this weed

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