New Soil Adjuvant Helps In Resistant Weed Control

New Soil Adjuvant Helps In Resistant Weed Control

In the face of continuing herbicide resistance, weed specialists are urging growers to apply one and, in some cases, two pre-emergent herbicide treatments to reduce the dependence on post-emergent sprays. To help in this effort, ORO-RZ, a new soil adjuvant, has been introduced by Oro Agri Inc. ORO-RZ has shown encouraging results in boosting pre-emergent herbicide control of tough broadleaf weeds.


In two consecutive years of university research field trials, the addition of ORO-RZ to popular, pre-emergent herbicide treatments significantly reduced the infestation of certified Roundup-resistant marestail in soybeans. ORO-RZ was added to a premium marestail pre-emergent treatment that was fall-applied preceding spring planting of soybeans. In both years, the ORO-RZ plus premium treatment provided a higher level of marestail control compared to the premium herbicide application alone. In Year 1, at 320 DAT, the ORO-RZ plot had 93% control versus 70% for the herbicide alone. Likewise in Year 2, the ORO-RZ application returned 87% control versus 72% control for the premium treatment alone at 296 DAT.

According to Riley Reynolds, Oro Agri Director of Sales and Marketing, the explanation behind the improved performance of soil-applied pesticides is fairly simple. ORO-RZ, with its great spreading and penetrating ability, helps the pre-emergent herbicide lay down a uniform blanket of protection to control germinating weed seedlings. It distributes the herbicide application evenly within the soil profile, even in hydroscopic soils. Adding ORO-RZ to the tank helps eliminate gaps in herbicide protection that allow weed emergence.”

For more in-depth information, including field trial results, go to

Please contact your local Oro Agri area sales manager for your closest ORO-RZ retailer.

ORO-RZ is not currently registered for use in California.

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