Weather for the Turf Industry
Research has shown that applications of 2,4-D + 2,4-DP ester applied to Kentucky bluegrass (Poa pratensis L.) controlled less than 60% of the dandelions present dandelion control when fewer than 130 base 50°F degree days had accumulated. Acceptable control (>80%) was achieved when the degree day accumulation exceeded 145.
For control with 2,4-D + 2,4-DP amine unacceptable control occurred with accumulation of less than 150 degree days, while acceptable control was indicated at degree day accumulations above 180.
These maps show areas of unacceptable (red dots), marginal (yellow dots) and favorable (green dots) dandelion control for these two herbicides.