Wild garlic (Allium vineale) has shown up in many Indiana no-till corn and soybean fields this spring especially, in southern Indiana. Wild garlic is most troublesome in wheat, where aerial bulblets contaminate harvested grain and impart the garlic flavor into processed products such as wheat flower. Infestations in corn and soybean fields have less adverse effects on the crop, but can spread quickly across fields and are difficult to control with typical burndown treatments of glyphosate and 2,4-D.
Management of wild garlic must occur early in the spring as this perennial will quickly become reproductive in mid to late spring. Wild garlic produces aerial bulblets and begins to senesce in late spring to early summer. As with all weeds, wild garlic management needs to occur prior to seed or in this case bulblet production to reduce future infestations.
Ideally herbicide applications should take place in early April when the wild garlic is less than 12 inches tall and actively growing. To assure active growth is occurring make applications when daytime temperatures are consistently maintained at 60 degrees or higher.
An additional challenge for herbicide application is the growth habit and leaf structure of wild garlic. The smooth, linear, and erect leaves of wild garlic can create difficulties in getting good spray coverage.
Spray carrier volume has the greatest effect on herbicide coverage, and higher volumes should be considered when making applications to difficult to cover weeds such as wild garlic. A minimum of 15 gal/acre would be recommended for effective coverage of wild garlic.
Typical spring no-till burndowns of glyphosate plus 2,4-D will only have marginal and variable control of wild garlic. The addition of thifensulfuron, thifensufluron plus tribenuron, or chlorimuron containing products to the glyphosate plus 2,4-D tank mix will provide additional and less variable control of wild garlic. Applications with higher rates of thifensulfuron will be most effective in controlling heavy infestations of wild garlic.
Again as mentioned above these herbicide applications will be most beneficial when applied at the correct timing and with higher carrier volumes.
Plant back restrictions for corn and soybean should be noted for the herbicide products applied. Products containing thifensulfuron and tribenuron can have plant back restrictions depending on product rates. The rotational restriction for corn should be 14 days and for soybean it should be 7 days.
If the soil is a sand or loamy sand or pH is above 7.9, the rotational interval is extended by 7 days for each crop. Chlorimuron products are not labeled for use prior to corn planting. Always refer to the label for plantback restrictions.
The list of products containing thifensufluron, thifensulfuron plus tribenuron, and chlorimuron is extensive and beyond the scope of this article. Additional information for control of wild garlic in winter wheat can be found in the “Control of Problem Weeds” section of the 2019 Weed Control Guide.