PPDL Picture of the Week

May 14, 2018


Joe Ikley, Weed Science Program Specialist, Department of Botany and Plant Pathology, Purdue University

As we emerge from our winter that seemed to hold on forever, you may have noticed an abundance of dandelion flowers and seedheads in the landscape. The weather last fall and this spring appears to have been conducive to allow dandelions to thrive in many habitats. While children will undoubtedly enjoy the abundance of seed to blow around, those who have to manage this weed know the challenges they can face every year, let alone when populations are as high as they are this year. Homeowners may be used to the yearly battle against this weed, but it can also thrive in no-till agricultural fields and on field edges.

Dandelion is a perennial weed that has a simple taproot and can reproduce from seed, or segments of the root. Seedlings can germinate from seed starting in late spring (after wind-blown seed lands in a suitable habitat) and throughout early fall. Mature dandelions will remain in a rosette that does not bolt or elongate. The only structure that bolts from the rosette produces the familiar yellow flower and puffy white seedhead. Being a perennial weed, control is most effective in the fall. The best time to apply herbicides in the fall for dandelion control is after the first light frost occurs and the plant begins moving nutrients into its taproot.

When dandelion appears in corn and soybean fields, there are a few options for control prior to planting in the spring. Dandelion can be effectively controlled with tillage prior to planting. If planting no-till soybeans, a combination of glyphosate plus 2,4-D ester plus a product containing either chlorimuron (Classic, others) or cloransulam (FirstRate) has been most effective in our research. If planting no-till corn, a combination of glyphosate plus 2,4-D ester plus a product containing atrazine and mesotrione (Lexar, Acuron, others) have been most effective in our research.

​Click image to enlarge

Figure 1. Dandelion rosette with yellow flowers.

Figure 2. A no-till production field with dandelions.

Figure 3. Dandelion thriving in a corn field in the spring.