Dandelion management in field and forage crops

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included.

Dandelion continues to be a serious problem in Michigan, mainly in no-tillage fields. Regular soil disturbance is effective at preventing the establishment of dandelion plants; however herbicide options are available to suppress dandelion in corn, soybean and alfalfa.

Research conducted at MSU in 2001-03 studied the control of dandelion in no-till corn and soybean. The results showed that herbicide applications of either glyphosate (0.75 lb a.e/A. + 17 lb/gal AMS) or 2,4-D ester (1 lb a.e./A) are more effective in the fall than in the spring. Additionally, 2,4-D ester was less effective than glyphosate in both fall or spring applications. Details on the results of this research are in the fact sheet, which also appears in the 2006 Weed Control Guide for Field Crops, pages 150-151.

The best approach to dandelion control is prior to planting a crop. However it is not uncommon for herbicides to provide less than complete control, especially if applied in the spring. What are options for dealing with uncontrolled dandelion following crop emergence? Where corn or soybeans have emerged and established dandelion are present, the strategy should be to suppress the plants to minimize yield loss from dandelion competition. In-season applications will significantly reduce dandelion competition but will likely not greatly reduce dandelion population. Then a fall application can be planned following harvest with the goal of actually removing the plants.

Corn. Several postemergence provide significant dandelion suppression. These are listed in the fact sheet, which also appears in the 2006 Weed Control Guide for Field Crops, pages 150-151.

Soybean. Glyphosate is the best option for postemergence suppression of established dandelion.

In established alfalfa, dandelion can be controlled with Velpar. The treatment can be made in the fall or spring; however the most effective timing for dandelion control is in the spring before the alfalfa has two inches of new growth. The best timing for maximum crop safety is early spring before the alfalfa breaks dormancy. The application rate for dandelion control is 1 lb ai/A. Velpar is not widely used for dandelion control due to cost and rotation crop restrictions. Dandelion control in Roundup Ready alfalfa can be achieved with an application glyphosate (0.75 lb a.e/A. + 17 lb/gal AMS).

Dr. Sprague's work is funded in part by MSU's AgBioResearch.

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