PPDL Picture of the Week
November 2, 2015
Common Dandelion
Travis Legleiter, Weed Science Professional Assistant, Botany & Plant Pathology Department, Purdue University
Common Dandelion is likely the plant species you think of
when the term “weed” is mentioned.
Almost everybody is familiar with its yellow ray flowers and puffy white
seed heads that you no doubt blew on when you were a child. As adults you learn to dislike those yellow
flowers and white seed heads as you tirelessly pull and spray them in your yard
and flower gardens. Dandelion is not
only a weed of residential yards and pastures, but can also become a problem in
agricultural fields. This perennial weed
is often overshadowed in agronomic fields by pesky summer annuals like
pigweeds, lambsquarters, and foxtails; but it can become a major pest itself in
long-term no-till fields especially in years like we have had in 2012.
Dandelion is a perennial weed that grows as a rosette and
uses a large taproot to overwinter and regrow year after year. Dandelion emerges in both the spring and fall
and grows most vigorously in these two seasons of cooler weather. Traditional agronomic practices that
included tillage limited the success of dandelion as tillage would bury the
small seeds below the soil surface and destroy the taproots; although shifts to
long-term no-till has lead to the increased prevalence of the perennial weed. The increased prevalence can also be
contributed to earlier growing seasons in which corn residual herbicides are
applied earlier and crops are harvested earlier. The lack of residual activity and earlier
canopy opening allows for dandelions to flourish in the fall following crop
maturity and harvest. This past growing
season of drought is likely to also contribute to increased dandelion pressure
as corn crops were abandoned, chopped, or harvested early due to poor growing
conditions. This in combination with
recent fall rainfalls will be very encouraging for dandelions in long-term no
till fields.
Control of dandelion in no-till fields starts with a good
burndown in the spring along with a residual herbicide for both corn and soybean. This burndown should include 2,4-D with
either glyphosate or gramaxone. Gramaxone
applied alone will provide an initial quick relief, but plants will rapidly
regrow shortly after application. The
use of a residual in both corn and soybeans will extend the control of
dandelion throughout the growing season.
The following products have exhibited the greatest control into the
season when applied with a proper burndown in Purdue University research
trials:
No-till Corn: Lumax, Fieldmaster, and Bicep II Magnum
No-till Soybean: Sencor,
Authority XL, and Valor