Using Zidua in celery

Benjamin Werling<werlingb@msu.edu>, Michigan State University Extension, and Sushila Chaudhari, Michigan State University Department of Plant, Soil and Microbial Sciences - June 04, 2020

Updated from an original article written by Benjamin Werling and Bernard Zandstra.

What does the herbicide Zidua bring to the table for celery growers?

Celery field with purslane — Common purslane can be a major issue in celery production, as shown in this picture. Zidua offers a new active ingredient with activity against this problem weed. Photo by Bernard Zandstra, MSU.

Both SC and 85WG formulations of the herbicide Zidua are labeled for use in celery via supplemental labels (Download the SC label. Download the 85WG label.). According to Weed Science Society of America, Zidua is a Group 15 herbicide; this group includes the more familiar herbicide Dual Magnum. It has only preemergence (PRE) activity on weeds and inhibits the root and shoot growth of susceptible germinating seedlings. It is labeled for use on muck soils with greater than 20% organic matter.

Comparison of Zidua, Chateau and Dual Magnum uses in celery.
Herbicide	Mode of action	PRE/POST activity on weeds	Application timing: Pre-transplant	Application timing: Post-transplant	Risk of injury
Zidua	15(K3)	PRE	No	1-6 days after transplanting	Chlorosis, stunting, stand reduction, and/or leaf burn if applied late or under stressful conditions.
Chateau	14(E)	PRE and POST	Before transplanting	3-7 days after transplanting	Chlorosis, leaf burn and/or stunting.
Dual Magnum	15(K3)	PRE	Surface or incorporated application before transplanting	Directed or over-the-top broadcast application after transplanting; 62-day PHI.	Chlorosis, stunting and/or leaf deformation. Crop injury risk: Preplant incorporated > pre-plant surface > post-plant over-the-top > post-plant-directed.

Weeds controlled

Zidua has PRE activity against annual weeds including common chickweed, common purslane, common groundsel, nightshade, pigweeds, smartweeds, marsh yellowcress and a variety of annual grasses including large crabgrass, fall panicum, sandbur and foxtails. Similar to Dual Magnum, it does not control emerged weeds.

PRE activity of Zidua, Dual Magnum and Chateau against select weed species. Information is from MSU Extension bulletin E0433.
Weed	Zidua	Dual Magnum	Chateau
Crabgrass, large	Good	Excellent	Good
Chickweed, Common	Good	None	Good
Groundsel, Common	Good	None	Good
Lambsquarter, Common	Fair	Fair	Excellent
Pigweeds	Good	Good	Excellent
Purslane, Common	Good	Fair	Good
Ragweed, Common	Poor	Poor	Fair
Sandbur	Good	Fair	None
Smartweeds, Ladysthumb	Good	Fair	Fair
Mustards, Wild Radish	Fair	Poor	Excellent
Yellow Nutsedge	Poor	Good	None

Application

The label states that Zidua be applied within one to six days of transplanting at 3.25 fluid ounces per acre (SC formulation) or 2 ounces per acre (85 WG formulation). It has no preharvest interval (PHI) when applied at this timing. There is a 12-hour restricted entry interval (REI).

Activation

After application, the product needs to be activated by half-inch of rainfall or irrigation.

Tank mixes

Until you gain experience with this herbicide, it is recommended to avoid tank-mixing it with other herbicides or adjuvants. The label has no tank-mix restrictions.

Crop safety

Bernard Zandstra, Michigan State University Extension weeds specialist, has observed good crop safety when applied within six days of transplanting, but stunting has been observed with experimental applications made three to four weeks post-transplant. The label warns that Zidua may cause crop injury under stressful conditions.

Rotational restrictions (assuming the labeled rate is applied in celery)

Field corn: 0 months
Small grains (besides wheat): 11 months
Soybeans: 0 months
Wheat: 1 month
Other crops: 18 months

How could Zidua help with common purslane control?

Zidua (long-chain fatty acid inhibitor) and Chateau (PPO-inhibitor) have different modes of action against common purslane. Rotating between them in different years may delay the evolution of resistant biotypes.

Could Zidua improve large crabgrass control?

Despite Zidua’s good activity, it may not improve control compared to post-transplant applications of Dual Magnum or Chateau. Similar to Dual magnum and Chateau, Zidua provides good control of annual grasses including large crabgrass. Unfortunately, large crabgrass likely germinates after residual activity of these herbicides wears off.

What is unique about the spectrum of weeds Zidua controls?

Zidua is unique among the preemergent herbicides in that it does have activity against smartweeds. If smartweed is an issue along with common purslane, it may be worth considering Zidua.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).