Plant morphology and the critical period of weed control

Abstract

The critical period of weed control (CPWC) provides a time frame in the life cycle of the crop for scouting or sensing weed populations and making weed control applications to prevent crop yield losses. This time frame is relatively early in the growing season for a given crop. Thus, newly emerged and small weed seedlings need to be observed prior to the start of the CPWC. Morphological characteristics of these seedlings are diverse and influence the ability to sense the seedlings at a given time, and account for the changes that have occurred over time. Understanding the population dynamics for different weed species, that is, emergence timing relative to the crop, types of cotyledons and leaf arrangements, and rates of leaf appearance and stem elongation, better scouting or sensing methods can be designed prior to the start of the CPWC. The development of new automated technologies must take into account changing morphology of weed seedlings early in the life cycle of the crop. Crop management practices influence the types and numbers of weed species present and thus can change the beginning and end of the CPWC and the timing for scouting and control.