Improving Weed Management Based on the Timing of Emergence Peaks: A Case Study of Problematic Weeds in Northeast USA

We reviewed the timing of peak rate emergence for 15 problematic weed species as well ways to use this knowledge improve control. Much previous literature modeled based on growing-degree-days. For these models, we input average temperature data from several zones Northeast USA. Within species, model-predicted in warmest and coolest differed by an 39 days. Also within there was some variation between likely reflecting different conditions study locations population-level differences that will need be addressed future modelling efforts. Summarizing both observed modelled results, typically peaked early-season barnyardgrass, Canada thistle, common lambsquarters, ragweed, giant foxtail, large crabgrass, perennial sowthistle, smooth crabgrass. Emergence mid-season hairy galinsoga, mouseear chickweed, red sorrel. late-season annual bluegrass. Several emerged a protracted manner, including quackgrass, redroot pigweed. With improved knowledge, farmers may target key particular field ways. Weed seedling control efforts can timed at highest densities or most vulnerable phenological stage. Residual herbicides suppressive mulches maximize effectiveness prior their breakdown. And if management flexibility allows, crop selection associated planting dates adjusted competition facilitate seedbank depletion through timely bare fallow periods. Such improvements become even more impactful predictive model reliability continues improve.